Use of Limestone Quarry By-Products for Developing Economical Self-Compacting Concrete

Home , Quarry

UNIVERSITY OF WISCONSIN SYSTEM SOLID WASTE RESEARCH PROGRAM

2004

Tarun R. Naik, Rudolph N. Kraus, & Yoon-moon Chun Center for By-Products Utilization University of Wisconsin-Milwaukee

FINAL TECHNICAL REPORT

Project Title: Use of Limestone Quarry By-Products for Developing Economical Self-Compacting Concrete

Covering Period: November 2002 to June 2003

Date of Report: January 15, 2004

Principal Investigator: Tarun R. Naik Director, UWM Center for By-Products Utilization University of Wisconsin-Milwaukee 3200 N. Cramer Street P.O. Box 784 Milwaukee, WI 53201 Ph: (414) 229-6696 Fax: (414) 229-6958 E-mail: [email protected]

Assistant Investigator: Rudolph N. Kraus Assistant Director, UWM Center for By-Products Utilization University of Wisconsin-Milwaukee Ph: (414) 229-4105 Fax: (414) 229-6958 E-mail: [email protected]

Executive Summary

BACKGROUND: By-product materials could reduce and/or replace concrete chemical admixtures, such as high-range water-reducing admixture (HRWRA) and viscosity-modifying admixture (VMA), and produce an economical self-compacting concrete (SCC) mixture.

OBJECTIVE: The primary objective of this project was to evaluate and explore the possibility to use limestone-quarry fines and other by-products such as coal fly ash and iron-foundry baghouse dust in the manufacturing of economical self-compacting concrete.

CONCLUSIONS: The limestone-quarry fines and Class C fly ash showed potential for utilization in the manufacturing of economical self-compacting concrete. The test data collected indicate that these materials can be used in the manufacturing of economical self-compacting concrete in different ways.

When quarry fine material was used for the substitute of natural sand, then it reduced the requirement of chemical admixtures (HRWRA and VMA) without affecting the strength of SCC. The 28-day compressive strength of the mixtures made with sand replaced with quarry fines was in the range of 7630 psi and 9150 psi, qualifying the mixtures to be classified as high-strength concrete (³ 6500 psi).

By using Class C fly ash for the replacement of up to 55% of total cement by mass, high- strength SCC with the 28-day strength in the range of 6900 psi and 10,200 psi was produced in an economical way.

The use of quarry fines and Class C fly ash significantly reduced the amount of expensive chemical admixtures in producing SCC.

Replacement of Class C fly ash with limestone-quarry fines did not result in any appreciable benefits from the aspects of cost and long-term strength of the self- compacting concrete.

Use of iron-foundry baghouse dust material as a partial replacement of Class C fly ash and sand did not reduce the use of chemical admixtures and, therefore, did not help reduce the cost of SCC directly. The use of foundry dust increased the air content and decreased the long-term strength of SCC. Therefore, a more extensive investigation should be conducted before arriving at a definite conclusion regarding the use of foundry dust in self-compacting concrete.

TABLE OF CONTENTS

LIST OF TABLES ...... v

LIST OF FIGURES ...... viii

LIST OF ACRONYMS AND ABBREVIATIONS...... x

INTRODUCTION...... 1

LITERATURE REVIEW ...... 2

Self-Compacting Concrete...... 2

Development of Mixture Proportions for Self-Compacting Concrete...... 4

Evaluation of Self-Compactability of Fresh Concrete...... 6

MATERIALS ...... 7

Overview of Selected Properties...... 7 Chemical Analysis, Minor Elements, BET Surface Area, Average Particle Size, and Other Properties ...... 7 SEM ...... 9 Particle Size Distribution...... 9

Portland Cement...... 12

Sand...... 12

Pea Gravel with 3/8-in. Maximum Size...... 14

Crushed Stone with 3/4-in. Maximum Size...... 15

Limestone-Quarry Fines ...... 17

Class C Fly Ash...... 18

Iron-Foundry Baghouse Dust...... 20

High-Range Water-Reducing Admixture (HRWRA)...... 22

Viscosity-Modifying Admixture (VMA)...... 23

MIXTURE PROPORTIONS, RESULTS, AND DISCUSSIONS ...... 25

Introduction...... 25

iii

Development of Control SCC Mixture Proportions ...... 25

Development of SCC Reference Mixture Using Class C Fly Ash...... 30

Use of Quarry Fines for Partial Replacement of Sand...... 33

Use of Quarry Fines for Partial Replacement of Class C Fly Ash...... 36

Use of Quarry Fines for Partial Replacement of Class C Fly Ash and Sand ...... 38

Use of Foundry Baghouse Dust for Partial Replacement of Class C Fly Ash and Sand ...... 41

ECONOMIC BENEFITS ANALYSIS...... 45

Cost of Materials...... 45

Material Cost and Compressive Strength of Concrete Mixtures ...... 46 Partial Replacement of Sand with Quarry Fines...... 46 Partial Replacement of Class C Fly Ash with Quarry Fines...... 47 Partial Replacement of Class C Fly Ash and Sand with Quarry Fines...... 49 Partial Replacement of Cement with Class C Fly Ash...... 50 Partial Replacement of Class C Fly Ash and Sand with Foundry Baghouse Dust ... 52

Potential Material-Cost Savings in Wisconsin ...... 53

SUMMARY AND CONCLUSIONS ...... 57

REFERENCES...... 61

APPENDIX: TEST METHODS FOR THE EVALUATION OF SELF- COMPACTABILITY OF FRESH CONCRETE...... 65

Slump-Flow Test...... 65

U-Flow Test ...... 66

V-Flow Test ...... 67

L-Box Test ...... 68

J-Ring Test ...... 69

LIST OF TABLES

Table 1. Chemical Analysis of Materials (% by mass) [24] ...... 7

Table 2. Minor Elements in Materials (ppm) [24]...... 8

Table 3. BET Surface Area and Average Particle Size of Materials [24] ...... 8

Table 4. Other Selected Properties of Materials [24]...... 9

Table 5. Chemical Composition of Portland Cement ...... 12

Table 6. Physical Properties of Portland Cement ...... 13

Table 7. Properties of Sand ...... 13

Table 8. Gradation of Sand ...... 13

Table 9. Properties of 3/8-in. Pea Gravel...... 14

Table 10. Gradation of 3/8-in. Pea Gravel...... 15

Table 11. Properties of 3/4-in. Crushed Stones ...... 16

Table 12. Gradation of 3/4-in. Crushed Stones...... 16

Table 13. Properties of Limestone-Quarry Fines...... 17

Table 14. Gradation of Limestone-Quarry Fines...... 18

Table 15. Physical Properties of Class C Fly Ash...... 19

Table 16. Gradation of Iron-Foundry Baghouse Dust ...... 21

Table 17. Physical Properties of Iron-Foundry Baghouse Dust in Comparison with ASTM C 618 Specifications ...... 22

Table 18. Manufacturer’s Recommended Dosage Rate of HRWRA ...... 23

Table 19. Manufacturer Provided Information On the Use of HRWRA...... 23

Table 20. Physical and Chemical Properties of HRWRA ...... 23

Table 21. Manufacturer’s Recommended Dosage Rate and Shelf Life of VMA...... 24

Table 22. Physical and Chemical Properties of VMA...... 24

Table 23. Trial Mixture Proportions 1 - 5...... 26

Table 24. Trial Mixture Proportions 6 - 10...... 27

Table 25. Trial Mixture Proportions 11 - 15, & 15R...... 28

Table 26. Compressive Strength of Mixtures 1 - 15, & 15R...... 30

Table 27. Mixture Proportions of SCC (Cement Replaced : Fly Ash = 1:1.25)...... 31

Table 28. Compressive Strength of Mixtures 15 - 21 (Cement Replaced : Fly Ash = 1:1.25)...... 32

Table 29. Mixture Proportions of SCC (Sand Replaced : Quarry Fines = 1:1)...... 34

Table 30. Compressive Strength of Mixtures 15, 15R, 18, and 22 - 27 (Sand Replaced : Quarry Fines = 1:1) ...... 35

Table 31. Mixture Proportions of SCC (Fly Ash Replaced : Quarry Fines = 1:1)...... 37

Table 32. Compressive Strength of Mixtures 15, 15R, 18, and 28 - 32 (Fly Ash Replaced : Quarry Fines = 1:1) ...... 38

Table 33. Mixture Proportions of SCC (Fly Ash Replaced : Quarry Fines = 1:2)...... 39

Table 34. Compressive Strength of Mixtures 15, 15R, 18, and 32 - 35 (Fly Ash Replaced : Quarry Fines = 1:2) ...... 40

Table 35. Mixture Proportions of SCC (Fly Ash Replaced : Foundry Baghouse Dust = 1:2)...... 42

Table 36. Compressive Strength of Mixtures 15, 15R, 18, and 36 - 40 (Fly Ash Replaced : Foundry Baghouse Dust = 1:2) ...... 44

Table 37. Cost of Materials...... 45

Table 38. Cost of Materials in SCC Mixtures Made with Partial Replacement of Cement with Class C Fly Ash, and Sand with Quarry Fines...... 46

Table 39. Cost of Materials in SCC Mixtures Made with Partial Replacement of Cement with Class C Fly Ash, and Class C Fly Ash with Quarry Fines...... 48

Table 40. Cost of Materials in SCC Mixtures Made with Partial Replacement of Cement with Class C Fly Ash, and Class C Fly Ash and Sand with Quarry Fines ...... 49

Table 41. Cost of Materials in SCC Mixtures Made with Partial Replacement of Cement with Class C Fly Ash...... 50

Table 42. Cost of Materials in SCC Mixtures Made with Partial Replacement of Cement with Class C Fly Ash, and Class C Fly Ash and Sand with Foundry Baghouse Dust...... 52

Table 43. Annual Consumption of Cement and Estimated Annual Production of Cement- Based Materials in Wisconsin ...... 54

Table 44. Potential Use of Class C Fly Ash and Quarry Fines in Self-Compacting Concrete and Material-Cost Savings in Wisconsin...... 55

Table 45. Estimated Total Cost of Materials Used in Self-Compacting Concrete (SCC) in Wisconsin as Influenced by the Market Share of SCC Containing Class C Fly Ash and Quarry Fines...... 56

Table 46. Potential Savings in the Cost of Materials Used in Self-Compacting Concrete (SCC) in Wisconsin with the Use of Class C Fly Ash and Quarry Fines ...... 56

vii

LIST OF FIGURES

Fig. 1. SEM of limestone-quarry fines...... 10

Fig. 2. SEM of Class C fly ash...... 10

Fig. 3. SEM of iron-foundry dust...... 11

Fig. 4. SEM of Type I portland cement ...... 11

Fig. 5. Particle size distribution of materials by sieve analysis combined with hydrometer analysis ...... 11

Fig. 6. Particle size distribution of sand by sieve analysis...... 14

Fig. 7. Particle size distribution of 3/8-in. pea gravel by sieve analysis ...... 15

Fig. 8. Particle size distribution of 3/4-in. crushed stones by sieve analysis...... 16

Fig. 9. Particle size distribution of limestone-quarry fines by sieve analysis combined with hydrometer analysis...... 18

Fig. 10. Particle size distribution of Class C fly ash by hydrometer analysis...... 20

Fig. 11. Particle size distribution of iron-foundry baghouse dust by sieve analysis combined with hydrometer analysis...... 21

Fig. 12. Material cost and compressive strength of SCC as influenced by partial replacement of sand with quarry fines (Mixtures 18 [Ref.], 22, 23, 24, 25, & 27) ...... 47

Fig. 13. Material cost and compressive strength of SCC as influenced by partial replacement of Class C Fly Ash with quarry fines (Mixtures 18 [Ref.], 28 - 32) ...... 48

Fig. 14. Material cost and compressive strength of SCC as influenced by partial replacement of Class C fly ash and sand with quarry fines (Mixtures 18 [Ref.], 33, 34, & 35)...... 50

Fig. 15. Material cost and compressive strength of SCC as influenced by partial replacement of cement with Class C fly ash (Mixtures 15R [Control], 18 [Ref.], 19, & 20)...... 51

Fig. 16. Material cost and compressive strength of SCC as influenced by partial replacement of Class C fly ash and sand with foundry baghouse dust (Mixtures 18 [Ref.], 36, 37, & 38)...... 53

viii

Fig. 17. Slump-flow test...... 65

Fig. 18. U-flow test [14] ...... 67

Fig. 19. L-box apparatus [21]...... 68

Fig. 20. J-ring test apparatus [23] ...... 69

LIST OF ACRONYMS AND ABBREVIATIONS

ACI American Concrete Institute ASTM American Society for Testing and Materials

fl oz fluid ounce HRWRA High-Range Water-Reducing Admixture (also called superplasticizer) VMA Viscosity-Modifying Admixture LOI Loss On Ignition SCC Self-Compacting Concrete, or Self-Consolidating Concrete SSD Saturated Surface-Dry w/cm water-cementitious materials ratio

INTRODUCTION

The scope of this project was to determine the usefulness of limestone-quarry by- product material from a lime company in Wisconsin in the development of economical self- compacting concrete (SCC). Class C fly ash received from a power plant in Wisconsin and foundry baghouse dust from an iron foundry in Wisconsin were also evaluated in this research. The main objective of this project was to evaluate the possibility for using these materials to reduce the amount of expensive chemical admixtures needed for the manufacturing of self-compacting concrete.

It has been established from other activities at the UWM Center for By-Products

Utilization (UWM-CBU) that the properties of a by-product can vary depending upon many unique situations under which the by-product is produced and collected. Therefore, it is important to determine physical, chemical, and morphological properties of the by-product before using it in SCC for a specific purpose.

LITERATURE REVIEW

Self-Compacting Concrete

Self-compacting concrete (SCC), a latest innovation in concrete technology, has numerous advantages over conventional concrete. Self-compacting concrete, as the name indicates, is a type of concrete that does not require external or internal compaction, because it becomes leveled and compacted under its self-weight. SCC can spread and fill every corner of the formwork, purely by means of its self-weight, thus eliminating the need of vibration or any type of compacting effort [1]. Self-compacting concrete, in its current reincarnation, was originally developed at the University of Tokyo, Japan, in collaboration with leading concrete contractors in the late 1980s. (Since the mid-1980s, flowable, self- leveling, self-compacting slurry has been gaining increasing acceptance [2]. However, such flowable slurry typically has compressive strength of 1,200 psi or less at the age of 28 days.)

The notion behind developing SCC was the concerns regarding the homogeneity and compaction of conventional cast-in-place concrete within intricate (i.e., heavily-reinforced) structures and to improve the overall strength, durability, and quality of concrete [3]. The

SCC concrete is highly flowable and cohesive enough to be handled without segregation. It is also referred to as self-consolidating concrete, self-leveling concrete, super-workable concrete, highly flowable concrete, non-vibrating concrete, etc. [4].

Hoshimoto et al. [5] visualized and explained the blocking mechanism of a heavily- reinforced section during the pouring of concrete and reported that the blockage of the flow of concrete at a narrow cross-section occurs due to the contact between coarse aggregates in concrete. When concrete flows between reinforcing bars, the relative locations of coarse aggregates are changed. This develops shear stress in the paste between the coarse

aggregates, in addition to compressive stress. For concrete to flow through such obstacles smoothly, the shear stress should be small enough to allow the relative displacement of the aggregate. To prevent the blockage of the flow of concrete due to the contact between coarse aggregates, a moderate viscosity of the paste is necessary. The shear force required for relative displacement largely depends on the water-cementitious materials ratio (w/cm) of the paste. An increase of the w/cm increases the flowability of the cement paste, however it also decreases the viscosity and deformability, the primary requirements for a SCC. The SCC is flowable as well as deformable without segregation [1, 2, 4]. Therefore, in order to maintain deformability along with flowability in paste, a superplasticizer is indispensable in such concretes. With a superplasticizer, the paste can be made more flowable with little concomitant decrease in viscosity [1]. An optimum combination of w/cm and superplasticizer for achievement of self-compatibility can be derived for fixed aggregate content concrete.

Mehta [6] and Neville [7] have suggested a simple approach of increasing the sand content, while reducing the amount of coarse aggregate by 4% to 5%, in order to avoid segregation. High-flowability requirement of SCC allows the use of higher amounts of mineral admixtures in its manufacturing. Use of mineral admixtures such as fly ash, blast furnace slag, limestone powder, etc., increases the fine materials of the concrete mixture [1].

The use of mineral admixtures also reduces the cost of concrete. The incorporation of one or more mineral admixtures, or powder materials having different morphology and grain-size distribution, can improve particle-packing density and reduce inter-particle friction and viscosity. Hence, it improves deformability, self-compatibility, and stability of the SCC [8].

By using fly ash and blast furnace slag, Yahia et al. [9], and Naik and Kumar [10] reported a reduction in the dosages of viscosity modifying agent and superplasticizer in SCC needed to obtain similar slump-flow compared to concrete made with portland cement only.

The well-known beneficial advantages of using fly ash in concrete, such as improved rheological properties and reduced cracking of concrete due to the reduced heat of hydration of concrete, can also be incorporated in SCC by utilization of this material as a filler. SCC often incorporates several mineral and chemical admixtures, in particular a superplasticizer and a viscosity-modifying admixture (VMA). The superplasticizer is used to insure high fluidity and reduce the w/cm. The VMA is incorporated to enhance the yield value and viscosity of the fluid mixture, hence reducing bleeding of the concrete. The homogeneity and uniformity of the SCC is not affected by the skill of workers, or the shape and bar arrangement of structures because of the high-fluidity and segregation-resisting power of materials used in SCC [1].

A highly flowable concrete is not necessarily self-compacting because SCC should not only flow under its own weight but also fill the entire form and achieve uniform compaction without segregation. Fibers are also sometimes used in SCC to enhance its tensile strength and to delay the onset of tension cracks due to heat of hydration resulting from high cement content in SCC [4]. Use of high-volume fly ash in SCC is also reported

[10, 11] for the development of economical and environmental friendly SCC.

Development of Mixture Proportions for Self-Compacting Concrete

SCC typically has higher content of fine particles and different flow properties. SCC has to have three essential properties when it is ready for placement: filling ability, resistance to segregation, and passing ability. However, its components are similar to other plasticized

concrete. SCC consists of cement, coarse and fine aggregates, and mineral & chemical admixtures. Self-compactability of concrete can be affected by the physical characteristics of materials and mixture proportioning. The mixture proportioning is based upon creating a high-degree of flowability while maintaining a low (< 0.40) w/cm. This is achieved by using high-range water-reducing admixture (HRWRA) combined with stabilizing agents, such as

VMA, to ensure homogeneity of the mixture [3].

A number of methods exist to optimize the concrete mixture proportions for self- compacting concrete. One of the optimization processes suggested by Campion and Jost [3] is given below:

1. W/cm equal to regular plasticized concrete, assuming the same required strength;

2. Higher volume of fines (for example, cement, fly ash, and mineral fines) than most

plasticized concrete;

3. Optimized gradation of aggregates; and

4. High dosage of HRWRA (0.5 to 2% by mass of cement; 460 to 1700 mL/100 kg of

cement, or 7 to 26 fl. oz/100 lb of cement), with VMA.

The simplest method for mixture proportioning for SCC was suggested by Okamura and Ozawa [1]. In this method:

1. Coarse aggregate content is fixed at 50% of the solid volume.

2. Fine aggregate is placed at 40% of the mortar fraction volume.

3. W/cm in volume is assured as 0.9 to 1.0 depending on properties of the cement.

4. Superplasticizer dosage and the final w/cm are determined so as to ensure the self-

compactability.

Several other design methods for SCC have also been reported [6, 7, 12]. However, a rational mixture proportioning method for SCC consisting a variety of finer materials is necessary. Optimum mixture is sensitive to small variations in the characteristics of the components, such as the type of sand & fillers (shape, surface, grading) and the moisture content of the sand. Success and failure of a good SCC mixture are relatively near to each other. Therefore, SCC cannot simply be made on the basis of a recipe.

Evaluation of Self-Compactability of Fresh Concrete

The essential characteristics of SCC lie in its behavior at fresh state. The fresh SCC should possess three essential properties—filling ability, resistance to segregation, and passing ability [1, 3, 4, 5, 13-19]. A number of self-compacting test methods such as slump- flow, U-flow, V-flow time, L-box, J-ring, and others are in use for the evaluation of self- compacting properties of the SCC. SCC test methods have two main purposes: One is to judge whether the concrete is self-compactable or not, and the other is to evaluate deformability or viscosity for estimating proper mixture proportionality if the concrete does not have sufficient self-compactability [19]. The most commonly used methods for this purpose are discussed briefly in Appendix (p. 65). In this research project, the slump-flow and U-flow tests were conducted, and the results are presented in the section MIXTURE

PROPORTIONS, RESULTS, AND DISCUSSIONS (p. 25).

MATERIALS

A test program was designed to measure properties of cement, sand, pea gravel, limestone-quarry fines, Class C fly ash, and iron-foundry dust materials. These properties were necessary before determining possible uses of these materials in developing economical

SCC. Properties of HRWRA and VMA were obtained from the manufacturer.

Overview of Selected Properties

Chemical Analysis, Minor Elements, BET Surface Area, Average Particle Size, and Other Properties

Results of chemical analysis, minor elements, BET surface area, average particle sizes, and other properties of the portland cement, quarry fines, foundry dust, and fly ash used in this research are presented in Tables 1 to 4 as determined by Pera [24]. Average particle sizes of crushed stones, pea gravel, and sand are also included in Table 3.

Table 1. Chemical Analysis of Materials (% by mass) [24]

Material Limestone- Class C Fly Ash Iron-Foundry Type I Portland Quarry Fines Dust Cement

SiO 2 n.d. 35.8 51.6 20.0 Al2O3 0.1 20.6 12.1 4.8 Fe2O3 n.d. 5.8 6.4 2.1 SiO 2 + Al2O3 + 0.1 62.2 70.1 26.8 Fe2O3 MnO n.d. n.d. 0.1 0.1 MgO 20.8 5.6 2.1 2.2 CaO 32.6 24.7 2.5 66.0

Na2O n.d. 2.2 1.3 0.2 K2O n.d. 0.5 0.7 0.5 TiO 2 n.d. 1.5 0.5 0.2 P2O5 n.d. 1.0 0.1 n.d. SO3 n.d. 1.2 0.8 2.5 LOI 46.5 1.2 22.0 1.4 n.d.: Not detected.

Table 2. Minor Elements in Materials (ppm) [24]

Material Limestone- Class C Fly Ash Iron-Foundry Type I Portland Quarry Fines Dust Cement As n.d. 18 4 8 Ba 27 6147 166 300 Cd n.d. 1 n.d. n.d. Cr 2 75 19 79 Cu 7 215 23 43 Ni 8 58 13 53 Pb n.d. 54 20 2 Sr 1869 2759 868 557 Zn n.d. 151 125 139 Zr 2 321 474 54 Large Amount of None None None None Toxic Elements n.d.: Not detected.

Table 3. BET Surface Area and Average Particle Size of Materials [24]

Material BET Surface Average Particle Average Particle Size Area (m2/g) Size by Laser by Sieve Analysis or Granulometry, Hydrometer Analysis,

D50 (mm) D50 (mm) Limestone-Quarry Fines 1.63 NA‡ 1,800 Class C fly ash 1.14* 13.3 13 Iron-Foundry Dust† 3.86 75 75 Type I Portland Cement 1.00 17 NA Sand NA NA 600 Pea Gravel NA NA 4,000 Crushed Stone NA NA 14,000

NA: Not available. * Very low BET surface area † Rather coarse, but 100% < 300 µm Þ can be used as filler after removal of organics. ‡ Laser granulometry not performed because the particles were too coarse.

Table 4. Other Selected Properties of Materials [24]

Material Minerals, Compounds Shape, Texture, Organics, Carbon, and Other Characteristics Limestone- Dolomite CaMg(CO3)2, Quarry Fines with traces of calcite (CaCO3) as shown in XRD (not given here). Class C Fly Ash Glassy phase + crystalline Agglomerated small spheres + larger minerals: quartz, particles (> 20 mm), Fig. 2. merwinite. periclase (MgO), and quicklime (CaO). Iron-Foundry Quartz + traces of calcite, • Infrared (IR) spectrometry: C-O bond at Dust anorthite and muscovite. 1453 cm-1 Þ presence of organics proved by high LOI (22.0%). • Irregular shape (SEM) and disordered surface. Type I Portland Rich in C3S. Low alkali portland cement (Equivalent Cement C4AF = 6.3% Na2O = Na2O + 0.658 K2O = 0.56%). C3A = 3.5% C2S = 6.5% C3S = 67.6%

SEM

Scanning electron micrographs (SEM) of limestone-quarry fines, Class C fly ash, iron-foundry dust, and Type I portland cement are presented in Fig. 1 through 4 [24].

Particle Size Distribution

Particle size distribution of the crushed stone, pea gravel, sand, quarry fines, foundry dust, and fly ash used in this research are presented together in Fig. 5 for comparison.

Fig. 1. SEM of limestone-quarry fines

(a) (b)

Fig. 2. SEM of Class C fly ash

Fig. 3. SEM of iron-foundry dust Fig. 4. SEM of Type I portland cement

100 90 80 Crushed Stone 70 Pea Gravel 60 Sand 50 40 Quarry Fines

Percent Finer 30 Foundry Dust 20 Fly Ash 10 0 1 10 100 1,000 10,000 100,000 Particle Diameter (µm)

Fig. 5. Particle size distribution of materials by sieve analysis combined with hydrometer analysis

Portland Cement

Chemical composition and physical properties of Type I portland cement used in this research are presented in Table 5 and Table 6, along with the requirements of ASTM

Standard Specification for Portland Cement (C 150). The cement met the standard chemical and physical requirements of ASTM.

Sand

Properties of the sand used in this research are presented in Table 7. Sieve analysis results are presented in Table 8 along with the grading requirements of ASTM Standard

Specification for Concrete Aggregates (C 33), and also in Fig. 6. The sand met the requirements of ASTM. The mean particle diameter (D50) of the sand was about 0.6 mm, or

600 µm.

Table 5. Chemical Composition of Portland Cement

Analysis Result ASTM C 150 (% by mass) (maximum) Silicon dioxide (SiO 2) 20.0 …

Aluminum oxide (Al2O3) 4.8 …

Ferric oxide (Fe2O3) 2.1 … MnO 0.1 Magnesium oxide (MgO) 2.2 6.0 Calcium oxide (CaO) 66.0 …

Na2O 0.2 …

K2O 0.5 …

TiO 2 0.2 …

Sulfur trioxide (SO3) 2.5 3.0 (when C3A £ 8%) 3.5 (when C3A > 8%) Loss on ignition (LOI) 1.4 3.0

Tricalcium aluminate (C3A) 3.5 …

Table 6. Physical Properties of Portland Cement

ASTM Test Result ASTM C 150 C 185 Air content of mortar (volume %) 8 £ 12 C 204 Fineness, specific surface, 340 ³ 280 by air permeability apparatus (m2/kg) C 151 Autoclave expansion (%) 0.06 £ 0.80 C 109 Compressive strength of cement mortars (psi): 1 day 2270 … 3 days 3860 ³ 1740 7 days 4640 ³ 2760 28 days 5800 … C 191 Time of setting by Vicat needle: Initial setting time (minutes) 115 ³ 45 £ 375 C 188 Density (g/cm3) 3.13 …

Table 7. Properties of Sand

ASTM C 136 C 29 C 29 C 128 C 128 C 128 C 128 Test Fineness Bulk Void Bulk specific Bulk specific Apparent Absorption, modulus density content gravity on gravity on specific or SSD† oven-dry SSD† basis gravity moisture basis content (lb/ft3) (%) (%)* Result 2.74 107 36 2.69 2.73 2.79 1.3

† Saturated surface-dry * % of oven-dry (105°C) mass

Table 8. Gradation of Sand

Amounts finer than each sieve (% by mass) Sieve 3/8-in. No. 4 No. 8 No. 16 No. 30 No. 50 No. 100 No. 200 Sieve openings 9.5 mm 4.75 mm 2.36 mm 1.18 mm 600 µm 300 µm 150 µm 75 µm Result 100 99 86 72 51 16 4 1.4* ASTM C 33 100 95 - 100 80 - 100 50 - 85 25 - 60 5 - 30 0 - 10 …

* Determined by washing in accordance with ASTM C 117.

100 90 80 70 60 50 40

Percent Finer 30 20 10 0 10 100 1000 10000 Sieve Size (µm)

Fig. 6. Particle size distribution of sand by sieve analysis

Pea Gravel with 3/8-in. Maximum Size

Properties of the pea gravel used as a coarse aggregate in this research are presented in Table 9. Sieve analysis results are presented in Table 10 along with the grading requirements of ASTM C 33, and also in Fig. 7. The pea gravel met the requirements of

ASTM, except that it had a somewhat higher amount of material passing 4.75 mm (No. 4) sieve. The mean particle diameter (D50) of the pea gravel was about 4 mm, or 4,000 µm.

Table 9. Properties of 3/8-in. Pea Gravel

ASTM C 29 C 29 C 127 C 127 C 127 C 127 Test Bulk Void Bulk specific Bulk specific Apparent Absorption, density content gravity on gravity on specific or SSD† oven-dry basis SSD† basis gravity moisture content (lb/ft3) (%) (%)* Result 106 35 2.62 2.68 2.79 2.3

† Saturated surface-dry * % of oven-dry (105°C) mass

Table 10. Gradation of 3/8-in. Pea Gravel

Amounts finer than each sieve (% by mass) Sieve 3/8-in. No. 4 No. 8 No. 16 No. 30 No. 50 No. 100 Sieve openings 9.5 mm 4.75 mm 2.36 mm 1.18 mm 600 µm 300 µm 150 µm Result 100 63 7 4 3 2 1 ASTM C 33, 90 - 100 20 - 55 5 - 30 0 - 10 … 0 - 5 … Size No. 89* * Nominal size of 3/8 in. to No. 16 (9.5 to 1.18 mm).

100 90 80 70 60 50 40

Percent Finer 30 20 10 0 10 100 1,000 10,000 Sieve Size (µm)

Fig. 7. Particle size distribution of 3/8-in. pea gravel by sieve analysis

Crushed Stone with 3/4-in. Maximum Size

A source of crushed angular stones with 3/4-in. maximum size was also used as a coarse aggregate in this research.

Properties of the crushed stones are presented in Table 11 along with the requirements of ASTM C 33. Sieve analysis results for the coarse aggregates are presented in Table 12 along with the grading requirements of ASTM C 33, and also in Fig. 8. The crushed stones with 3/4-in. maximum size met the requirements of ASTM. The mean particle diameter (D50) of the crushed stones was about 14 mm, or 14,000 µm.

Table 11. Properties of 3/4-in. Crushed Stones

† Saturated surface-dry * % of oven-dry (105°C) mass

Table 12. Gradation of 3/4-in. Crushed Stones

Amounts finer than each sieve, mass percent Sieve 1 in. 3/4 in. 1/2 in. 3/8 in. No. 4 No. 8 Sieve openings (mm) 25.0 19.0 12.5 9.5 4.75 2.36 Result 100 92 37 14 0 0 ASTM C 33, Size No. 6* 100 90 - 100 20 - 55 0 - 15 0 - 5 … * Nominal size of 3/4 to 3/8 in. (19.0 to 9.5 mm).

100 90 80 70 60 50 40

Percent Finer 30 20 10 0 100 1,000 10,000 100,000 Sieve Size (µm)

Fig. 8. Particle size distribution of 3/4-in. crushed stones by sieve analysis

Limestone-Quarry Fines

The limestone-quarry by-product used in this research was “crushed limestone screenings” received from a lime company in Wisconsin.

The material was white to light gray in color. The as-received moisture content of the quarry fines was not very high, at around 3% of oven-dry material (105°C) by mass.

Moisture content in this range may be useful for dust control during handling, shipping, and storing.

Properties of the limestone-quarry fines are presented in Table 13. The quarry fines showed higher dry-rodded bulk density than sand and pea gravel used in this research. This was attributed to the presence of considerable amount of fine materials. Gradation of the limestone-quarry fines is presented in Table 14. Particle size distribution of the quarry fines by sieve analysis combined with hydrometer analysis is presented in Fig. 9. The mean particle diameter (D50) of the quarry fines is about 1.8 mm, or 1,800 µm. The quarry fines dust is much coarser than the Class C fly ash (Fig. 10). The amount of material passing 45

µm (No. 325) sieve is 9% for the quarry fines and 87% for the fly ash.

Table 13. Properties of Limestone-Quarry Fines

ASTM C 136 C 29 C 29 C 127 C 127 C 127 C 127 Test Fineness Bulk Void Bulk specific Bulk specific Apparent Absorption, modulus density content gravity on gravity on specific or SSD† oven-dry SSD† basis gravity moisture basis content (lb/ft3) (%) (%)* Result 3.49 122 27 2.71‡ 2.75‡ 2.83‡ 1.6‡

† Saturated surface-dry * % of oven-dry (105°C) mass ‡ Determined by using material retained on 2.36 mm (No. 8) sieve

Table 14. Gradation of Limestone-Quarry Fines

Amounts finer than each sieve (% by mass) Sieve 3/8-in. No. 4 No. 8 No. 16 No. 30 No. 50 No. 100 No. 200 No. 325 Sieve 9.5 mm 4.75 mm 2.36 mm 1.18 mm 600 µm 300 µm 150 µm 75 µm 45 µm openings Result 100 77 55 40 32 27 20 10* 9†

* Determined by washing in accordance with ASTM C 117. † Determined by wet-sieving in accordance with ASTM C 430.

100 90 80 70 60 50 40

Percent Finer 30 20 10 0 1 10 100 1,000 10,000 Particle Diameter (µm)

Fig. 9. Particle size distribution of limestone-quarry fines by sieve analysis combined with hydrometer analysis

Class C Fly Ash

Physical properties of the Class C fly ash used in this research are presented in Table

15. The fly ash met the physical requirements of ASTM C 618 for Class C fly ash.

Cement activity index tests for the Class C fly ash were performed in accordance

with ASTM C 311 and C 109. Two-inch mortar cubes were made in a prescribed manner

using a mixture of cement, sand, and water (Control Mixture). Compressive strength tests

were conducted at the age of 3, 7, 14, and 28 days. Test mixtures were prepared by replacing

20% by mass of cement with the Class C fly ash. The test results show higher values (104% at 7 days and 113% at 28 days) than the minimum required value of Strength Activity Index per ASTM C 618 (75%). In fact, mortar cubes made with 20% replacement of cement with the Class C fly ash showed even higher strength than the Control Mixture containing only portland cement (100%).

Table 15. Physical Properties of Class C Fly Ash

Test Class C Fly ASTM C 618 Ash Requirements for Class C Fly Ash Fineness, amount retained when wet-sieved 13 £ 34 on 45 µm (No. 325) sieve (%) Strength Activity Index with Cement at 7 ³ 75 or 28 days (% of Control) 3 days 109 7 days 104 14 days 102 28 days 113 Water Requirement (% of Control) 91 £ 105 Autoclave Expansion or Contraction (%) - £ 0.8 Specific Gravity 2.56 …

The water requirement for the test mortar mixtures containing Class C fly ash (91%) was nine percentage points lower compared with the Control Mixture (100%). It is well established that the lower the water required for a desired value of workability for the cement-based material, the higher the overall quality of the product made from the material.

It was, therefore, concluded that this fly ash should perform quite satisfactorily in SCC and other cement-based composites.

Particle size distribution of Class C fly ash by hydrometer analysis is presented in

Fig. 10. The mean particle diameter (D50) of this fly ash was about 13 µm.

100 90 80 70 60 50 40

Percent Finer 30 20 10 0 1 10 100 1,000 Particle Diameter (µm)

Fig. 10. Particle size distribution of Class C fly ash by hydrometer analysis

Iron-Foundry Baghouse Dust

The foundry baghouse dust used in this research was “sand system baghouse dust” received from an iron foundry in Wisconsin. A baghouse is a device in which particulates are removed from a stream of exhaust gases as the stream passes through a large cloth bag.

As-received moisture content of the foundry baghouse dust was around 2%. Sieve analysis results are presented in Table 16. The material passing 45 µm (No. 325) sieve upon wet-sieving was 40%. This result indicates that this foundry dust is much finer than the limestone-quarry fines. Particle size distribution of the iron-foundry baghouse dust by sieve analysis combined with hydrometer analysis is shown in Fig. 11. The iron-foundry baghouse dust is finer than the limestone-quarry fines (Fig. 9) and coarser than the Class C fly ash

(Fig. 10). The mean particle size (D50) of the foundry dust is about 75 µm. The amount of fines less than 125 µm in diameter is considered as powder and is very important for the rheology of the SCC [18]. A minimum amount of fines arising from cementitious materials,

fillers, and sand is needed to avoid segregation [18]. Approximately 74% of the iron-

foundry dust was finer than 125 µm.

Table 16. Gradation of Iron-Foundry Baghouse Dust

* Determined by washing in accordance with ASTM C 117. † Determined by wet-sieving in accordance with ASTM C 430.

100 90 80 70 60 50 40

Percent Finer 30 20 10 0 1 10 100 1,000 10,000 Particle Diameter (µm)

Fig. 11. Particle size distribution of iron-foundry baghouse dust by sieve analysis combined with hydrometer analysis

The foundry baghouse dust is neither natural pozzolan nor coal fly ash. However, for

comparison purpose, its properties were compared with ASTM C 618 specifications. The

foundry baghouse dust did not meet the fineness requirement, Table 17. The foundry

baghouse dust met the water requirement for natural pozzolan, but showed slightly lower

strength activity index than the minimum of 75% specified by ASTM C 618.

Table 17. Physical Properties of Iron-Foundry Baghouse Dust in Comparison with ASTM C 618 Specifications

Test Iron- ASTM C 618 Specifications Foundry Class N Class C Class F Baghouse (Natural Fly Ash Fly Ash Dust Pozzolan) Fineness, amount retained when wet- 60* £ 34 £ 34 £ 34 sieved on 45 µm (No. 325) sieve (%) Strength Activity Index with Cement at 7 ³ 75 ³ 75 ³ 75 or 28 days (% of Control) 3 days 68 7 days 66 14 days 69 28 days 60 Water Requirement (% of Control) 112 £ 115 £ 105 £ 105 Autoclave Expansion or Contraction (%) - £ 0.8 £ 0.8 £ 0.8 Specific Gravity 2.20 - - -

* 53% when sample passing a 150 µm (No. 100) sieve was used. Corrected for the whole sample.

High-Range Water-Reducing Admixture (HRWRA)

A proprietary copolymer HRWRA that complies with the requirements of ASTM

Standard Specification for Chemical Admixtures for Concrete (C 494) for Type F, High

Range Water Reducing Admixture (HRWRA), was used as a HRWRA in this research.

The manufacturer’s recommended dosage rate (or addition rate) of the HRWRA is shown in Table 18.

Information provided by the manufacturer on the use of the HRWRA is presented

Table 19.

Key physical and chemical properties of the HRWRA based on the material safety data sheet (MSDS) provided by the manufacturer are presented in Table 20.

Table 18. Manufacturer’s Recommended Dosage Rate of HRWRA

Admixture Dosage Rate Dosage Rate (fl oz/100 lb of cementitious (mL/100 kg of cementitious materials) materials) HRWRA 2 - 14 130 - 910

Table 19. Manufacturer Provided Information On the Use of HRWRA

Admixture Time of Concrete Placement Chemicals for Extending the Shelf Life Slump Retention HRWRA Within 20 minutes after the Retarding Admixture Minimum 6 addition of HRWRA months

Table 20. Physical and Chemical Properties of HRWRA

Admixture HRWRA Appearance Brownish liquid Solubility in Water 100% Specific Gravity 1.06 pH 5 - 8

Viscosity-Modifying Admixture (VMA)

The manufacturer’s recommended dosage rate (or addition rate) and shelf life of the

VMA used in this research are shown in Table 21.

Key physical and chemical properties of the VMA, based on the MSDS provided by the manufacturer, are presented in Table 22.

Table 21. Manufacturer’s Recommended Dosage Rate and Shelf Life of VMA

Admixture Dosage Rate Dosage Rate Shelf Life (fl oz/100 lb of (mL/100 kg of cementitious materials) cementitious materials) VMA 2 - 14 130 - 920 Minimum 8 months

Table 22. Physical and Chemical Properties of VMA

Appearance Light brown liquid Odor None Solubility In Water Soluble Specific Gravity 1.002 pH 8.07

MIXTURE PROPORTIONS, RESULTS, AND DISCUSSIONS

Introduction

Self-compacting concrete typically has a higher content of fine particles and different flow properties than the conventional concrete. It has to have three essential properties when it is ready for placement: filling ability, resistance to segregation, and passing ability.

However, the components of SCC are similar to other plasticized concrete. Self- compactability of concrete can be affected by the physical characteristics of materials, mixture proportioning, and moisture content of its ingredients. The mixture proportioning is based upon creating a high-degree of flowability, while maintaining a low (< 0.40) w/cm.

Development of SCC mixtures typically requires a series of trial mixtures.

In order to develop SCC mixtures efficiently, only the compressive strength of SCC was determined for the initial stage of the laboratory investigation. A series of concrete mixtures were produced using different by-product materials, and the compressive strength of concrete was determined by testing three 4" ´ 8" cylinders per each test age for each mixture.

Development of Control SCC Mixture Proportions

In order to develop a control mixture for the project, a number of trial mixture proportions were used in the study. The mixture proportions and other details about fresh properties of SCC trial mixtures are presented in Tables 23 to 25.

Table 23. Trial Mixture Proportions 1 - 5

Mixture Number 1* 2* 3 4 5 Cement (lb/yd3) 460 760 540 591 583 Sand (lb/yd 3) 1430 1400 1160 1030 1032 3/8 " Pea Gravel 1865 2012 (lb/yd 3) Coarse Aggregate 2000 1805 2055 (lb/yd 3) Water (lb/yd 3) 244 350 270 290 239 HRWRA (gal./yd3) 4 6.6 1.2 0.8, 1.5** 1.5 VMA (gal./yd3) 3 2.7 2.4 1.5 1.9 w/cm 0.53 0.46 0.50 0.49 0.41 w/cm† 0.63 0.54 0.55 0.52 0.45 Slump-Flow (in.) 21 24 24 19, 21.5** 21.5 Segregation Yes Yes Yes Yes Yes Bleeding Yes Yes Less Yes Air Content (%) NA NA NA NA 1.6 Density (lb/ft3) NA NA 140.0 144.7 144.4 Date of Casting 01/02/03 01/03/03 01/06/03 01/06/03 01/09/03 Notes Requirement Requirement of more fines of more fines was clearly was clearly visible. visible.

* Mixture proportions not modified based on yield value. ** Initial amount and total amount of HRWRA and corresponding slump-flow values. † Considering water in chemical admixtures. NA: Not available.

Table 24. Trial Mixture Proportions 6 - 10

Mixture Number 6 7 8 9 10 Cement (lb/yd3) 580 560 588 681 687 Sand (lb/yd 3) 1006 1020 1070 1442 1429 3/8 " Pea Gravel (lb/yd3) 0 1935 0 1415 1455 ¾" Crushed Stones (lb/yd3) 2012 0 2032 0 0 Water (lb/yd 3) 263 233 230 293 273 HRWRA (gal./yd3) 1.5 1.5, 2.5, 1.5, 2.6, 1, 2* 1, 2* 3.5, 4.2* 3.6, 4.3* VMA (gal./yd3) 1.9 1.8 1.8 1 1 w/cm 0.45 0.42 0.39 0.43 0.40 w/cm† 0.49 0.49 0.46 0.46 0.43 Slump-Flow (in.) 25.5 18.5, 22, 20, 24.5, 20, 25.5* 20.5, 23.5, 25* 26, 27.5* 25.5* Segregation None Some Yes Negligible Yes Bleeding None NA None Some NA Air Content (%) 1.7 3.5 1.5 1.5 2.4 Density (lb/ft3) 143.0 140.5 142.3 143.3 143.2 Date of Casting 01/09/03 01/10/03 01/10/03 01/14/03 01/14/03

* Initial quantity, intermediate (if any) quantities, and total quantity of HRWRA and corresponding slump-flow values. † Considering water in chemical admixtures. NA: Not available.

Table 25. Trial Mixture Proportions 11 - 15, & 15R

Mixture Number 11 12 13 14 15* 15R# (Control)* Cement (lb/yd3) 663 668 681 706 700 727 Sand (lb/yd 3) 1476 1577 1564 1577 1575 1636 3/8 " Pea Gravel 1443 1376 1390 1414 1414 1468 (lb/yd 3) Water (lb/yd 3) 273 241 222 185 187 248 HRWRA 0, 1, 2, 2, 2, 3‡ 2, 4, 4.9‡ 5, 6.5, 5.75 1.64 (gal./yd 3) 2‡ 7.5‡ VMA (gal./yd3) 0, 0, 0, 1, 2, 2‡ 1, 1, 2‡ 2 2 0.75 2‡ w/cm 0.41 0.36 0.33 0.27 0.27 0.34 w/cm† 0.45 0.41 0.39 0.35 0.34 0.36 Slump-Flow (in.) 13, 17.5, 20, 26‡ 14.5, 12.5, 22, 26.5 26.75 27, 27, 21.5, 26‡ 26‡ 27‡ Segregation NA Less Very little Some Some Some Bleeding NA Some Negligible Slight None Some U-Flow, H1 - H2 NA NA NA NA 1.75 0.2 (in.) U-Flow, H2/H1 NA NA NA NA 86 98 (%) Air Content (%) 2.5 2.4 2.0 1.5 1.5 1.7 Density (lb/ft3) 143.0 144.5 144.6 146.6 148.0 151.8 Date of Casting 01/16/03 01/16/03 01/21/03 01/23/03 02/04/03 06/18/03

* Made with newly delivered HRWRA. # Repeat of Mixture 15 ‡ Initial, intermediate (if any), and total quantities of HRWRA and VMA, and corresponding slump-flow values. † Considering water in chemical admixtures. NA: Not available.

A total of 15 mixture proportions were used for the initial development of the control

SCC mixture. Mixtures 1 to 13 cannot be classified as SCC as they seldom met the characteristics of fresh SCC. Mixture 14 was accepted as SCC based upon its behavior as fresh SCC. However, the requirement of HRWRA was very high, 7.5 gal./yd3. After studying the manufacturer’s supplied information on the use of the HRWRA, it was found that the HRWRA used up to that point in the project was very old and had expired active life.

Therefore, Mixture 14 was repeated with fresh HRWRA (Mixture 15). The fresh SCC properties of Mixture 15 were satisfactory, and the amount of HRWRA was also reduced from 7.5 gal./yd3 to 5.75 gal./yd3. In addition, Mixture 15 was nearly twice as high strong as

Mixture 14 (Table 26). Later, Mixture 15R was made with the same proportions as Mixture

15, except using much lower dosages of HRWRA and VMA than Mixture 15. Mixture 15R was selected as the Control SCC for comparison of results with mixtures containing quarry fines and other by-products.

Compressive strength results for concrete Mixtures 1 to 15, and 15R are presented in

Table 26. Mixture 15 showed much higher strength than Mixtures 1 - 14. Mixture 15R

(Control) showed higher strength than Mixture 15.

Table 26. Compressive Strength of Mixtures 1 - 15, & 15R

Mixture Compressive Strength (psi) No. 3-day 4-day 5-day 7-day 10-day 28-day 91-day 1 … … 725 870 … 1340 … 2 3600 … 4040 … 4280 … 3 1190 … … 1570 … 2120 … 4 1530 … … 2285 … 2550 … 5 … 2265 … 2490 … 3210 … 6 … 2065 … 2110 … 2640 … 7 2115 … … 2475 … 2390 … 8 2335 … … 3115 … 3315 … 9 2815 … … 3715 … 4710 … 10 2395 … … 3650 … 4340 … 11 … … … 3145 … 3950 … 12 … … 2815 … 3105 3280 … 13 3650 … … 3995 … 4590 … 14 3455 … … 4140 … 4665 … 15* 5700 … … 7345 … 8380 … 15R (Control)* 6530 … … … … 8650 9790

* Newly received HRWRA was used.

Development of SCC Reference Mixture Using Class C Fly Ash

In order to develop a SCC mixture that would be the basis for mixtures that will use quarry fines and foundry baghouse dust, a series of mixtures used Class C fly ash to replace a part of cement in Control SCC mixture. The cement was replaced with fly ash at a fly ash- cement replaced ratio of 1.25 by mass. SCC mixtures were made by replacing 20%, 35%,

45%, and 55% of cement with fly ash. The mixture proportions and other details of the SCC mixtures containing fly ash, as well as those of Mixture 15R (Control) are given in Table 27.

The required amounts of HRWRA and VMA for achieving the target slump-flow of

26.5 to 28 in. decreased drastically as the replacement level of cement with fly ash increased from 0% to 35%. At 45% and 55% replacement levels of cement with fly ash, the required

amounts of HRWRA and VMA still further decreased to some extent. The requirements for

the total amount of HRWRA and VMA for the Control SCC Mixture 15R were 1.64 and

0.75 gal./yd 3, respectively, whereas the requirements were 0.6 and 0.36 gal./yd3,

respectively, for Mixture 20 made with 55% replacement of cement with fly ash. Also, with

the replacement of cement with fly ash, U-flow test results improved. In all the mixtures

(Mixtures 15 to 21), the T50cm measured during slump-flow test was between 3-6 seconds.

Table 27. Mixture Proportions of SCC (Cement Replaced : Fly Ash = 1:1.25)

Mixture Number 15R 16 17 18 (Ref.) 19 20 21* (Control) % Replacement of 0 35 20 35 45 55 45 Cement with Fly Ash Cement (lb/yd3) 727 464 560 447 385 306 385 Fly Ash, Class C 0 313 178 300 393 480 393 (lb/yd 3) Sand (lb/yd 3) 1636 1610 1601 1556 1588 1582 1580 3/8 " Pea Gravel 1468 1448 1450 1424 1454 1453 1453 (lb/yd 3) Water (lb/yd 3) 248 208 214 239 229 212 228 HRWRA 1.64 4.3 2.1 0.96 0.6 0.6 0.6 (gal./yd 3) VMA (gal./yd3) 0.75 1 1 0.6 0.4 0.36 0.4 w/cm 0.34 0.29 0.30 0.35 0.33 0.31 0.33 w/cm† 0.36 0.34 0.33 0.37 0.34 0.32 0.34 Slump-Flow (in) 26.75 27.5 28 27 27 27.5 27 Segregation Some Some None NA NA NA NA Bleeding Some None None Some Some None Slight U-Flow, H1 - H2 0.2 0.25 0.25 0.25 0.25 0.25 0.25 (in.) U-Flow, H2/H1 98 98 98 98 98 98 98 (%) Air Content (%) 1.7 0.3 1.5 1.5 1.4 2.7 1.1 Density (lb/ft3) 151.8 151.3 148.2 147.3 150.1 149.6 150.0 Date of Casting 06/18/03 02/05/03 02/07/03 02/10/03 02/11/03 02/18/03 02/27/03

* Repeat of Mixture No. 19. † Considering water in chemical admixtures. NA: Not available.

Compressive strength results for Mixtures 15R (Control) to 21 are presented in Table

28. The results for Mixture 15 are also included to provide a basis for comparison of the 7-

day strength, because the 7-day strength for Mixture 15R (Control) is not available and the

strength results of Mixtures 15 and 15R are nearly comparable at 3 and 28 days.

Table 28. Compressive Strength of Mixtures 15 - 21 (Cement Replaced : Fly Ash = 1:1.25)

Mixture Cement Compressive Strength (psi) No.‡ Repl. (%)* 3-day 4-day 5-day 6-day 7-day 28-day 56-day 91-day 182-day 15 0 5700 … … … 7345 8380 … … … 15R 0 6530 … … … … 8650 … 9790 … (Control) 17 20 … 6475 … … 7725 10180 … … … 16 35 4855 … … … 6585 9250 … … … 18 (Ref.) 35 4140 … … … 6310 9055 … … … 19 45 205 … … … 4405 8650 9915 10560 11090 21† 45 … 3630 4260 4725 5100 7690 … 9785 … 20 55 130 150 215 330 1245 6930 … … …

‡ Arranged in ascending order of cement replacement with fly ash. * Replacement of cement with Class C fly ash. † Repeat of Mixture 19.

Overall, as the replacement level of cement with fly ash increased from 0% to 20%,

35%, 45%, and 55%, the 3-day compressive strength of SCC decreased. The decrease in

strength was probably due to longer initial-setting time and final-setting time of SCC

containing a considerable amount of fly ash [25].

However, with the increase in age, concrete with a replacement of cement with fly

ash gained considerable strength. The strength of Mixture 17, made with 20% replacement

of cement with fly ash, was somewhat higher than that of Mixture 15 at 7 days, and

considerably higher strength than that of Mixture 15R (Control) at 28 days. SCC mixtures

made with 35% replacement of cement with Class C fly ash (Mixtures 16 and 18) showed almost equivalent 7-day strength compared with Mixture 15 and higher 28-day strength compared with Mixture 15R (Control).

SCC mixtures made with 45% (Mixtures 19 and 20) and 55% (Mixture 20) replacements of cement with fly ash showed very low 3-day strength, and the mixture made with 55% replacement of cement showed low 7-day strength. However, the 28-day strength of the SCC mixtures with 45% fly ash was equivalent to that of Control Mixture 15R.

Mixture 20 with 55% fly ash showed a considerable strength gain after the age of 7 days, and its 28-day strength was nearly equivalent to that of Control Mixture 15R.

Based upon the fresh SCC test results and compressive strength, Mixture 18 was selected as the reference mixture for incorporating quarry fines and iron-foundry dust.

Use of Quarry Fines for Partial Replacement of Sand

For evaluating the effect of quarry fines in SCC, Mixture 18 (35% replacement of cement with fly ash) was selected as the reference for this series of mixtures. Limestone- quarry fines were used to replace 10%, 20%, 30%, 40%, and 50% of the sand used in

Mixture 18 on a replacement ratio of 1:1 by mass. The mixture proportions and other details of the mixtures incorporating quarry fines as a replacement of sand, as well as those of the

Reference Mixture 18, are given in Table 29.

Regardless of the replacement level of sand with quarry fines, the requirement of

VMA remained approximately the same as the Reference Mixture 18, probably because the quarry fines are angular material replacing rounded natural sand. However, the requirement of HRWRA decreased gradually as the replacement level of sand with quarry fines increased.

Table 29. Mixture Proportions of SCC (Sand Replaced : Quarry Fines = 1:1)

Mixture Number 18 22 23 24 25 26* 27 (Ref.) % Replacement of 35 35 35 35 35 35 35 Cement with Fly Ash % Replacement of 0 10 20 30 40 50 50 Sand with Quarry Fines Cement (lb/yd3) 447 450 455 460 457 542 459 Fly Ash, Class C 300 301 304 307 307 361 306 (lb/yd 3) Sand (lb/yd 3) 1556 1416 1262 1123 963 951 806

Quarry Fines 0 156 319 476 641 951 806 (lb/yd 3) 3/8 " Pea Gravel 1424 1432 1438 1454 1445 951 1451 (lb/yd 3) Water (lb/yd 3) 239 241 243 245 244 289 245 HRWRA (gal./yd3) 0.96 0.8, 0.9‡ 0.8 0.5, 0.7, 0.53, 0.64, 0.53, 0.7‡ 0.66‡ 0.64‡ 0.66‡ VMA (gal./yd3) 0.6 0.4, 0.6‡ 0.55 0.43, 0.53, 0.50, 0.43, 0.43, 0.53‡ 0.63‡ 0.53‡ 0.55‡ w/cm 0.35 0.35 0.35 0.35 0.35 0.35 0.35 w/cm† 0.37 0.36 0.36 0.36 0.36 0.36 0.36 Slump-Flow (in.) 27 26, 27‡ 28, 28, 25, 28, 24, 31, 24, 28‡ 27‡ 26.5‡ 27.5‡ 27.5‡ Segregation NA None NA NA NA NA NA Bleeding Some None Some Some None None None U-Flow, H1 - H2 0.25 0.25 0.25 0.25 0.375 0.375 0.375 (in.) U-Flow, H2/H1 (%) 98 98 98 98 97 97 97 Air Content (%) 1.5 0.9 0.7 0.5 0.9 0.6 0.5 Density (lb/ft3) 147.3 148.0 149.5 151.0 150.6 150.3 151.2 Date of Casting 02/10/03 03/04/03 03/05/03 03/06/03 03/06/03 03/07/03 03/07/03

* In Mixture 26, by mistake, 44% less pea gravel was used than intended. Therefore, Mixture 27 is the originally intended mixture with 50% of sand replacement with quarry fines. ‡ Initial, intermediate (if any), and total quantities of HRWRA and VMA, and corresponding slump-flow values. † Considering water in chemical admixtures. NA: Not available.

Compressive strength results for Mixtures 15, 15R (Control), 18 (Reference), and 22 through 27 are presented in Table 30. When sand was replaced with quarry fines, compressive strength either increased, or sometimes decreased to some extent. Overall, the

3-day and 7-day strengths were slightly higher, and the 28-day strength was somewhat lower compared with Reference Mixture 18. The 28-day strength of concrete made with partial replacement of cement with Class C fly ash combined with partial replacement sand with quarry fines, was equivalent to that of the Control Mixture 15R made without Class C fly ash or quarry fines. Since sand occupies considerable volume in SCC concrete mixtures, replacement of sand with quarry fines can be considered an economical high-volume use option for quarry fines.

Table 30. Compressive Strength of Mixtures 15, 15R, 18, and 22 - 27 (Sand Replaced : Quarry Fines = 1:1)

Mixture Cement Sand Compressive Strength (psi) No. Repl. (%)* Repl. (%)† 3-day 7-day 28-day 56-day 91-day 182-day 15 0 0 5700 7345 8380 … … … 15R 0 0 6530 … 8650 … 9790 … (Control) 18 (Ref.) 35 0 4140 6310 9055 … … … 22 35 10 4200 6365 8800 9315 10505 10945 23 35 20 4355 6290 7630 9830 9765 9745 24 35 30 4510 6665 9150 10225 11060 10600 25 35 40 3655 6500 8730 10335 11150 11215 26‡ 35 50 4600 7595 9745 10850 12150 10945 27 35 50 5080 6875 8300 10500 9740 11375 Avg.# 35 30 4360 6540 8520 10040 10440 10780

* Replacement of cement with Class C fly ash. † Replacement of sand with limestone-quarry fines. ‡ In Mixture 26, by mistake, 44% less pea gravel was used than intended. # Average of results for Mixtures 22, 23, 24, 25, and 27 (excluding Mixture 26).

Use of Quarry Fines for Partial Replacement of Class C Fly Ash

The reference SCC mixture used to evaluate the quarry fines as a replacement of

Class C fly ash was Mixture 18 (35% replacement of cement with fly ash). The mixture proportions and other details of the SCC mixtures are given in Table 31. Up to 50% of fly ash was replaced by quarry fines at 1:1 ratio by mass. In general, somewhat lower performance in slump-flow and U-flow tests were observed as the replacement of fly ash with quarry fines increased. The required quantity of VMA remained approximately the same regardless of the replacement level of fly ash with quarry fines. The required quantity of HRWRA remained approximately the same as Reference Mixture 18, up to 30% replacement of fly ash with quarry fines. No bleeding was observed in these mixtures.

However, at 40% and 50% replacement levels of fly ash with quarry fines, HRWRA dosage increased. Some segregation of concrete was also observed at these high replacement levels.

Compressive strength results for Mixtures 15, 15R (Control), 18 (Reference), and 28 to 32 are presented in Table 32. Overall, the replacement of fly ash with quarry fines resulted in little change in the 3-day compressive strength and considerable reduction in the

28-day strength. In the range of 10% to 50% replacement of fly ash with quarry fines, there were small variations in strength between the mixtures made with different replacement levels of fly ash. Usually as the percentage replacement of fly ash with quarry fines increased, the long-term compressive strength of concrete decreased. However, peak long- term compressive strength, not considering Reference Mixture 18 (0% fly ash replacement), was observed at 20% replacement of fly ash with quarry fines (Mixture 29).

Table 31. Mixture Proportions of SCC (Fly Ash Replaced : Quarry Fines = 1:1)

Mixture Number 18 28 29 30 31 32 (Ref.) % Replacement of Cement 35 35 35 35 35 35 % Replacement of Fly Ash 0 10 20 30 40 50 with Quarry Fines Cement (lb/yd3) 447 446 445 439 448 455 Fly Ash, Class C (lb/yd3) 300 268 236 202 175 153 Sand (lb/yd 3) 1556 1547 1543 1521 1556 1584 Quarry Fines (lb/yd 3) 0 32 63 93 127 153 3/8 " Pea Gravel (lb/yd3) 1424 1421 1417 1396 1429 1455 Water (lb/yd 3) 239 245 244 233 238 226 HRWRA (gal./yd3) 0.96 0.9, 0.9‡ 0.9 0.8, 0.9‡ 0.8, 1.0, 0.8, 1.4, 1.6, 1.2, 1.3‡ 1.7‡ VMA (gal./yd3) 0.6 0.54, 0.6 0.6, 0.6‡ 0.6, 0.6, 0.6, 0.6, 0.6, 0.6‡ 0.6, 0.6‡ 0.7‡ w/cm 0.35 0.37 0.38 0.39 0.40 0.39 w/cm† 0.37 0.39 0.40 0.40 0.43 0.42 Slump-Flow (in.) 27 27.5, 26 24, 25‡ 24, 24, 20.5, 23.5, 26‡ 25, 25‡ 24, 24.5‡ Segregation NA NA NA NA Some* Some* Bleeding Some None None None NA NA U-Flow, H1 - H2 (in.) 0.25 0.1875 0.5 0.5 1 2 U-Flow, H2/H1 (%) 98 98 96 96 92 84 Air Content (%) 1.5 2.0 3.0 2.8 1.8 1.8 Density (lb/ft3) 147.3 146.5 146.0 144.2 148.0 150.0 Date of Casting 02/10/03 03/25/03 03/26/03 03/27/03 03/27/03 04/01/03

‡ Initial, intermediate (if any), and total quantities of HRWRA and VMA, and corresponding slump-flow values. † Considering water in chemical admixtures. * Thus, the need for more power (< 0.125 mm) was evident. NA: Not available.

Table 32. Compressive Strength of Mixtures 15, 15R, 18, and 28 - 32 (Fly Ash Replaced : Quarry Fines = 1:1)

Mixture Cement Fly Ash Compressive Strength (psi) No. Repl. (%)* Repl. (%)† 3-day 7-day 28-day 56-day 91-day 182-day 15 0 0 5700 7345 8380 … … … 15R 0 0 6530 … 8650 … 9790 … (Control) 18 (Ref.) 35 0 4140 6310 9055 … … … 28 35 10 4045 5615 7510 8760 8990 9515 29 35 20 3820 5030 7550 8885 9275 10180 30 35 30 3940 5580 7095 8190 8745 8995 31 35 40 3910 5520 6745 7370 8230 8735 32 35 50 4235 5350 6555 7365 7240 8375 Avg.# 35 30 3990 5420 7090 8110 8500 9160

* Replacement of cement with Class C fly ash. † Replacement of Class C fly ash with limestone-quarry fines. # Average of results for Mixtures 28 - 32.

Use of Quarry Fines for Partial Replacement of Class C Fly Ash and Sand

Quarry fines were used to replace 10%, 20%, and 30% of fly ash at a replacement ratio of 1:2 (fly ash : quarry fines). The additional quarry fines in the mixtures were used for replacement of 2%, 4%, and 6% of sand. The mixture proportions and other details of the

SCC mixtures are presented in Table 33. Overall, the required quantities of HRWRA and

VMA remained approximately the same for up to 20% replacement of fly ash with quarry fines. At 30% replacement of fly ash, the requirements of HRWRA and VMA increased somewhat.

Comparison of the effects of the different replacement ratios (1:1 versus 1:2 for fly ash replaced : quarry fines) on fresh properties of SCC (Table 31 and Table 33) shows that overall the HRWRA and VMA demands and the slump-flow and U-flow performance were about the same for both ratio for fly ash replacement level of up to 30% with quarry fines.

Table 33. Mixture Proportions of SCC (Fly Ash Replaced : Quarry Fines = 1:2)

Mixture Number 18 (Ref.) 33 34 35 % Replacement of Cement 35 35 35 35 with Fly Ash % Replacement of Fly Ash 0 10 20 30 with Quarry Fines Cement (lb/yd3) 447 445 448 450 Fly Ash, Class C (lb/yd3) 300 267 238 207 Sand (lb/yd 3) 1556 1507 1493 1466 Quarry Fines (lb/yd 3) 0 63 127 191 3/8 " Pea Gravel (lb/yd3) 1424 1413 1429 1434 Water (lb/yd 3) 239 243 238 230 HRWRA (gal./yd3) 0.96 0.83 0.84 0.84, 1.01, 1.14* VMA (gal./yd3) 0.6 0.62 0.63 0.63, 0.63, 0.74* w/cm 0.35 0.37 0.37 0.37 w/cm† 0.37 0.39 0.39 0.39 Slump-Flow (in.) 27 26.5 26.5 26 Segregation NA None None Negligible Bleeding Some None None NA U-Flow, H1 - H2 (in.) 0.25 0.25 0.25 0.375 U-Flow, H2/H1 (%) 98 98 98 97 Air Content (%) 1.5 3.3 2.7 1.8 Density (lb/ft3) 147.3 146 147.9 148.4 Date of Casting 02/10/03 04/08/03 04/08/03 04/09/03

* Initial, intermediate (if any), and total quantities of HRWRA and VMA, and corresponding slump-flow values. † Considering water in chemical admixtures. NA: Not available.

Compressive strength results for Mixtures 15, 15R (Control), 18 (Reference), and 33 to 35 are presented in Table 34. Overall, the replacement of fly ash with quarry fines using a replacement ratio of 1:2 (fly ash replaced : quarry fines) resulted in a reduction in the 3-day compressive strength and a considerable reduction in the 28-day strength. In the range of

10% to 30% replacement of fly ash, there were relatively small variations in strength between the mixtures made with a different replacement level of fly ash. The peak long-term

compressive strength was observed at 10% replacement of fly ash with quarry fines (Mixture

33).

Table 34. Compressive Strength of Mixtures 15, 15R, 18, and 32 - 35 (Fly Ash Replaced : Quarry Fines = 1:2)

Mixture Cement Fly Ash Compressive Strength (psi) No. Repl. (%)* Repl. (%)† 3-day 7-day 28-day 56-day 91-day 182-day 15 0 0 5700 7345 8380 … … … 15R 0 0 6530 … 8650 … 9790 … (Control) 18 (Ref.) 35 0 4140 6310 9055 … … … 33 35 10 3570 5745 7855 8960 9425 10325 34 35 20 3450 5345 7500 8850 8830 9470 35 35 30 3975 5055 7560 8125 9090 9185 Avg.# 35 20 3670 5380 7640 8650 9120 9660 Avg.‡ 35 20 3940 5410 7390 8610 9000 9560

* Replacement of cement with Class C fly ash. † Replacement of Class C fly ash with limestone-quarry fines at a replacement ratio of 1:2. # Average of results for Mixtures 33 - 35. ‡ Average of results for Mixtures 28 - 30, excluding Mixtures 31 and 32, made with fly ash replaced : quarry fines ratio of 1:1.

Comparison of the average compressive strength results presented in Table 34 for the two replacement ratios (1:1 versus 1:2 for fly ash replaced : quarry fines) shows that the average compressive strength of SCC mixtures made by using 1:2 ratio was slightly lower at the ages of 3 and 7 days, and slightly higher at later ages than the SCC mixtures made by using 1:1 ratio. Essentially, the strength of SCC was the same regardless of the ratio used.

Since properties of fresh SCC mixtures were also comparable, the use of more quarry fines by using 1:2 ratio should be more economically beneficial than using 1:1 ratio.

In effect, the above comparison affirms that the replacement of natural sand with quarry fines does not significantly affect the fresh properties and strength of SCC.

Due to the partial replacement of fly ash with quarry fines, regardless of whether the

1:1 ratio or the 1:2 ratio was used, the strength of SCC made with quarry fines was lower than that of the Reference Mixture 18 made without quarry fines. The 3, 28, and 91-day strength of SCC containing quarry fines were lower compared with Control Mixture 15R due to a partial replacement of cement with fly ash. However, it should be noted that the average

3-day compressive strength of SCC incorporating quarry fines was almost 4000 psi, strong enough for building concrete structures. In fact, the SCC with quarry fines can be classified as high-strength concrete because the 28-day compressive strength exceeded 6500 psi.

Use of Foundry Baghouse Dust for Partial Replacement of Class C Fly Ash and Sand

The foundry baghouse dust used in this research is a by-product material from the iron-foundry industry. To investigate the utilization aspect of this material in SCC, foundry dust was used in some SCC mixtures. The baghouse dust was used as a fly ash replacement material. A replacement ratio 1:2 (fly ash : foundry dust) by mass was used for the replacement of 10%, 20%, and 30% of Class C fly ash. The additional foundry dust was incorporated as a replacement of 2%, 4%, and 6% of sand. The mixture proportions and other details of the SCC mixtures containing foundry baghouse dust, as well as those of

Mixture 18 (Reference), are given in Table 35.

Table 35. Mixture Proportions of SCC (Fly Ash Replaced : Foundry Baghouse Dust = 1:2)

Mixture Number 18 (Ref.) 36 37 38 39 40 % Replacement of 35 35 35 35 35 35 Cement with Fly Ash % Replacement of Fly 0 10 20 30 10 10 Ash with Foundry Baghouse Dust Cement (lb/yd3) 447 442 440 425 422 445 Fly Ash, Class C (lb/yd3) 300 264 232 194 281 265 Sand (lb/yd 3) 1556 1350 1342 1238 1317 1358 Foundry Baghouse Dust 0 62 123 179 59 62 (lb/yd 3) 3/8 " Pea Gravel 1424 1397 1389 1343 1332 1405 (lb/yd 3) Water (lb/yd 3) 239 233 232 223 418.5 234 HRWRA (gal./yd3) 0.96 0.82 0.73, 0.80,1.18 0 0.82 1.14* , 2.0* VMA (gal./yd3) 0.6 0.52 0.51, 0.40, 0 0.51 0.51* 0.40, 0.40* w/cm 0.35 0.36 0.37 0.38 0.48, 0.50, 0.36 0.54, 0.59, 0.65‡ w/cm† 0.37 0.37 0.39 0.41 0.65 0.37 Slump-Flow (in.) 27 28 28.5 28.5 14, 16, 20.5, 27.5 23, 26‡ Segregation NA None None None Some None Bleeding Some None None None None None U-Flow, H1 - H2 (in.) 0.25 0.125 0.125 0.125 0.125 0.125 U-Flow, H2/H1 (%) 98 99 99 99 99 99 Air Content (%) 1.5 7** 7.3** 10** 0.2 6.9** Density (lb/ft3) 147.3 138.8 139.8 132.4 141.8 139.4 Date of Casting 02/10/03 04/15/0 04/16/0 04/18/03 04/22/03 04/24/0 3 3 3 Note Concrete Concrete not appears very blackish. cohesive.

† Considering water in chemical admixtures. * Initial, intermediate (if any), and total quantities of HRWRA and VMA. ‡ Initial, intermediate, and final values of w/cm, and corresponding slump-flow values. ** Air-entraining admixture was not used. NA: Not available.

The addition of the foundry baghouse dust in SCC drastically increased the air content from 1.5% to between 7 to 10% without the use of any air-entraining admixture and, consequently, deceased the density of concrete. Further, with the increase in foundry dust content, the color of the concrete became dark gray (or black). The required amount of

VMA decreased slightly with the increase in the replacement of fly ash with foundry dust.

Beyond a replacement level of 20%, the requirement of HRWRA increased considerably.

Slump-flow was in the range of 28 to 28.5 in. and U-flow was 99%.

To ascertain the cause of higher value of air content, Mixture 39 was produced (Table

35). In this concrete mixture, no chemical admixtures (HRWRA or VMA) were used. The air content obtained in this case was very low, 0.2%. However, to obtain the desired slump- flow, high water content was necessary. Mixture 40 (Table 35) was produced to verify the high air content of Mixture 36. Mixture 40 was made with HRWRA and VMA, and similar to Mixture 36, and again produced high air content. The cause of the high air content of

Mixtures 36, 37, 38, and 40 is believed to be some reaction between the foundry dust and the chemical admixtures. The presence of organics was noted for the foundry baghouse dust

(Table 4). In order to come at some definite conclusion, more experimental work is required.

Compressive strength results for Mixtures 18 and 36 to 40 are presented in Table 36.

Overall, compared with Reference Mixture 18, some reduction in the 3-day strength and considerable reduction in the 7-day and 28-day strengths were observed with 10 to 30% replacement of fly ash with foundry dust. This was attributed to reduced amount of fly ash and high air content of concrete with the use of foundry dust.

Table 36. Compressive Strength of Mixtures 15, 15R, 18, and 36 - 40 (Fly Ash Replaced : Foundry Baghouse Dust = 1:2)

Mixture Cement Fly Ash Compressive Strength (psi) No.** Repl. (%)* Repl. (%)† 3-day 4-day 7-day 28-day 56-day 91-day 182-day 15 0 0 5700 … 7345 8380 … … … 15R 0 0 6530 … … 8650 … 9790 … (Control) 18 (Ref.) 35 0 4140 … 6310 9055 … … … 36 35 10 3360 … 4645 6140 6675 7020 7935 40 35 10 … 4080 5075 7520 7480 8940 9595 37 35 20 3675 … 5280 6830 6905 … 8285 38 35 30 2775 … 3875 4945 5355 … 5840 Avg.# 35 18 3270E … 4720 6360 6600 … 7910 39‡ 35 10 1280 … 1820 3800 … 5020 5810

** Arranged in ascending order to fly ash replacement with foundry dust. * Replacement of cement with Class C fly ash. † Replacement of Class C fly ash with iron-foundry baghouse dust at a replacement ratio of 1:2. ‡ Made without using HRWRA or VMA. This mixture had high w/cm. # Average of results for Mixtures 36, 37, 38, and 40, excluding Mixture 39. E Average excluding Mixtures 39 and 40.

ECONOMIC BENEFITS ANALYSIS

Use of Class C fly ash and quarry fines in self-compacting concrete is expected to provide significant economic benefits to coal-powered power plants, quarries, and concrete producers in Wisconsin.

Cost of Materials

In order to compare the material cost of various self-compacting concrete (SCC) mixtures, the pricing information on cement, HRWRA, and VMA were obtained from their respective manufacturers. The prices of the other materials were assigned based on the available market information. Table 37 presents the cost of the materials. The cost of quarry fines is zero, assuming that the cost of transporting the quarry fines to the concrete producer equals the avoided disposal cost otherwise incurred by the quarry. Usually being disposed of on-site and free of hazardous contaminants, the quarry fines have a lower disposal cost than other types of industrial by-products. The cost of foundry baghouse dust is negative $20 due to the avoided disposal cost.

Table 37. Cost of Materials

Cost Cost Cost ($/2000 ($/lb) ($/gal.) lbs) Cement 90 0.045 … Fly Ash, Class C 40 0.020 … Sand 8 0.004 … Quarry Fines 0 0 … Foundry Baghouse Dust -20 -0.010 … Pea Gravel 8 0.004 … HRWRA … … 17 VMA … … 10

Material Cost and Compressive Strength of Concrete Mixtures

Mixture proportions influenced the material cost and compressive strength of the self-compacting concrete (SCC) mixtures produced in this research. Changes in material cost and strength of SCC are compared in this section.

Partial Replacement of Sand with Quarry Fines

As shown in Table 38 and Fig. 12, replacement of up to 50% of natural sand with quarry fines lowered the material cost of self-compacting concrete slightly and did not affect the strength of the concrete significantly. About 70% of the savings in the material cost were due to the reduced dosage of HRWRA, and most of the remaining savings were directly due to partial replacement of sand with quarry fines. All of the concrete mixtures showed relatively high 3-day compressive strength, ranging from 3655 psi to 5080 psi. The 28-day compressive strength of the concrete mixtures was in the range of 7630 and 9150 psi, qualifying the concrete mixtures to be classified as high-strength concrete.

Table 38. Cost of Materials in SCC Mixtures Made with Partial Replacement of Cement with Class C Fly Ash, and Sand with Quarry Fines

Mixture No. 18 22 23 24 25 27 (Ref.) % Replacement of 35 35 35 35 35 35 Cement with Fly Ash % Replacement of Sand 0 10 20 30 40 50 with Quarry Fines Cement ($/yd3) 20 20 20 21 21 21 Fly Ash, Class C ($/yd 3) 6 6 6 6 6 6 Sand ($/yd3) 6 6 5 4 4 3 Quarry Fines ($/yd3) 0 0 0 0 0 0 Foundry Dust ($/yd 3) 0 0 0 0 0 0 Pea Gravel ($/yd 3) 6 6 6 6 6 6 HRWRA ($/yd 3) 16 15 14 12 11 11 VMA ($/yd3) 6 6 6 6 5 5 Total ($/yd3) 60 59 56 55 53 52

120

100

80 91-day str. (100 psi) 28-day str. (100 psi) 60 60 59 56 55 53 52 3-day str. (100 psi) 40 Material Cost ($/yd3) 20

0 0 10 20 30 40 50 60 Replacement of Sand with Quarry Fines (%) (35% of cement replaced with fly ash)

Fig. 12. Material cost and compressive strength of SCC as influenced by partial replacement of sand with quarry fines (Mixtures 18 [Ref.], 22, 23, 24, 25, & 27)

Partial Replacement of Class C Fly Ash with Quarry Fines

Replacement of up to 30% of Class C fly ash with quarry fines reduced the material cost of self-compacting concrete by a small amount (by up to 5%). However, replacement of

40% and 50% of Class C fly ash with quarry fines required the use of more HRWRA and increased the total material cost of the concrete mixtures considerably (Table 39, Fig. 13).

Partial replacement of Class C fly ash with quarry fines did not affect the 3-day compressive strength of concrete, but it did reduce the 28-day strength of concrete (Fig. 13). Also, replacement of Class C fly ash, which is a cementitious and pozzolanic material, with practically inert limestone-quarry fines is expected to decrease the durability of concrete.

Table 39. Cost of Materials in SCC Mixtures Made with Partial Replacement of Cement with Class C Fly Ash, and Class C Fly Ash with Quarry Fines

Mixture No. 18 28 29 30 31 32 (Ref.) % Replacement of 35 35 35 35 35 35 Cement with Fly Ash % Replacement of Fly 0 10 20 30 40 50 Ash with Quarry Fines Cement ($/yd3) 20 20 20 20 20 20 Fly Ash, Class C ($/yd 3) 6 5 5 4 4 3 Sand ($/yd3) 6 6 6 6 6 6 Quarry Fines ($/yd3) 0 0 0 0 0 0 Foundry Dust ($/yd 3) 0 0 0 0 0 0 Pea Gravel ($/yd 3) 6 6 6 6 6 6 HRWRA ($/yd 3) 16 15 15 15 22 29 VMA ($/yd3) 6 6 6 6 6 7 Total ($/yd3) 60 59 58 57 64 72

100

80 72 91-day str. (100 psi) 64 60 60 59 58 57 28-day str. (100 psi) 40 3-day str. (100 psi) Material Cost ($/yd3) 20

0 0 10 20 30 40 50 60 Replacement of Class C Fly Ash with Quarry Fines (%) (Ref.: 35% cement replacement with fly ash)

Fig. 13. Material cost and compressive strength of SCC as influenced by partial replacement of Class C Fly Ash with quarry fines (Mixtures 18 [Ref.], 28 - 32)

Partial Replacement of Class C Fly Ash and Sand with Quarry Fines

Up to 20% replacement Class C fly ash with quarry fines, combined with up to 4% replacement of sand with quarry fines, reduced the material cost of self-compacting concrete mixtures by about 5% (Table 40, Fig. 14). However, 30% replacement of Class C fly ash, combined with 6% replacement of sand with quarry fines, increased the material cost by 5% compared with 0% replacement of fly ash, because more HRWRA had to be used in producing the self-compacting concrete.

Overall, the material cost of the concrete mixtures was more or less the same.

However, the long-term strength of concrete decreased because of partial replacement of

Class C fly ash with quarry fines (Fig. 14).

Table 40. Cost of Materials in SCC Mixtures Made with Partial Replacement of Cement with Class C Fly Ash, and Class C Fly Ash and Sand with Quarry Fines

Mixture No. 18 33 34 35 (Ref.) % Replacement of 35 35 35 35 Cement with Fly Ash % Replacement of Fly 0 10 20 30 Ash with Quarry Fines Cement ($/yd3) 20 20 20 20 Fly Ash, Class C ($/yd 3) 6 5 5 4 Sand ($/yd3) 6 6 6 6 Quarry Fines ($/yd3) 0 0 0 0 Foundry Dust ($/yd 3) 0 0 0 0 Pea Gravel ($/yd 3) 6 6 6 6 HRWRA ($/yd 3) 16 14 14 19 VMA ($/yd3) 6 6 6 7 Total ($/yd3) 60 57 57 63

100

80 91-day str. (100 psi) 63 60 60 57 57 28-day str. (100 psi) 40 3-day str. (100 psi) Material Cost ($/yd3) 20

0 0 10 20 30 40 Replacement of Class C Fly Ash and Sand with Quarry Fines (% of Initial Fly Ash) (Ref.: 35% cement replacement with fly ash)

Fig. 14. Material cost and compressive strength of SCC as influenced by partial replacement of Class C fly ash and sand with quarry fines (Mixtures 18 [Ref.], 33, 34, & 35)

Partial Replacement of Cement with Class C Fly Ash

Partial replacement of portland cement with Class C fly ash lowered the material cost

(Table 41, Fig. 15) and the early-age strength of self-compacting concrete (Fig. 15), and increased the long-term strength of concrete (Fig. 15).

Table 41. Cost of Materials in SCC Mixtures Made with Partial Replacement of Cement with Class C Fly Ash

Mixture No. 15R 18 19 20 (Control) (Ref.) % Replacement of 0 35 45 55 Cement with Fly Ash Cement ($/yd3) 33 20 17 14 Fly Ash, Class C ($/yd 3) 0 6 8 10 Sand ($/yd3) 7 6 6 6 Quarry Fines ($/yd3) 0 0 0 0 Foundry Dust ($/yd 3) 0 0 0 0 Pea Gravel ($/yd 3) 6 6 6 6 HRWRA ($/yd 3) 28 16 10 10 VMA ($/yd3) 8 6 4 4 Total ($/yd3) 81 60 52 49

120

100

80 81 91-day str. (100 psi) 28-day str. (100 psi) 60 60 52 49 3-day str. (100 psi) 40 Material Cost ($/yd3) 20

0 0 10 20 30 40 50 60 Replacement of Cement with Class C Fly Ash (%) (Contains no other by-products)

Fig. 15. Material cost and compressive strength of SCC as influenced by partial replacement of cement with Class C fly ash (Mixtures 15R [Control], 18 [Ref.], 19, & 20)

About 60% of the savings in the cost of materials for the SCC were due to the reduction in the required quantity of HRWRA for producing self-compacting concrete mixtures—which is in fact due to the partial replacement of cement with fly ash. Almost

30% of the savings were directly because of the partial replacement of cement with fly ash, and the rest of the savings were due to the reduced dosage of VMA.

The 3-day compressive strength of the concrete made with 35% replacement of cement with Class C fly ash (Mixture 18 [Ref.]) was 4140 psi, which was actually quite high at that early age. Mixtures 18 (Ref.), 19, and 20 made with 35%, 45%, and 55% replacement of cement with fly ash showed the 28-day compressive strength of 9055, 8650, and 6930 psi, respectively. Thus they can be classified as high-strength concrete (³ 6,500 psi). Moreover, although the durability of concrete was not determined in this research, it is well known by

the concrete community that the use of fly ash improves the durability of concrete significantly.

Partial Replacement of Class C Fly Ash and Sand with Foundry Baghouse Dust

Overall, partial replacement of Class C fly ash and sand with foundry baghouse dust increased the material cost (because more HRWRA had to be used) and decreased both the early-age and the late-age compressive strength of self-compacting concrete (Table 42, Fig.

16). Also, it is expected that the durability of concrete would decrease because of the partial replacement of Class C fly ash with foundry baghouse dust.

Table 42. Cost of Materials in SCC Mixtures Made with Partial Replacement of Cement with Class C Fly Ash, and Class C Fly Ash and Sand with Foundry Baghouse Dust

Mixture No. 18 36 37 38 (Ref.) % Replacement of 35 35 35 35 Cement with Fly Ash % Replacement of Fly 0 10 20 30 Ash with Quarry Fines Cement ($/yd3) 20 20 20 19 Fly Ash, Class C ($/yd 3) 6 5 5 4 Sand ($/yd3) 6 5 5 5 Quarry Fines ($/yd3) 0 0 0 0 Foundry Dust ($/yd 3) 0 -1 -1 -2 Pea Gravel ($/yd 3) 6 6 6 5 HRWRA ($/yd 3) 16 14 19 34 VMA ($/yd3) 6 5 5 4 Total ($/yd3) 60 55 59 70

100

80 70 60 60 28-day str. (100 psi) 55 59 3-day str. (100 psi) 40 Material Cost ($/yd3) 20

0 0 10 20 30 40 Replacement of Class C Fly Ash and Sand with Foundry Dust (% of Initial Fly Ash) (Ref.: 35% cement replacement with fly ash)

Fig. 16. Material cost and compressive strength of SCC as influenced by partial replacement of Class C fly ash and sand with foundry baghouse dust (Mixtures 18 [Ref.], 36, 37, & 38)

Potential Material-Cost Savings in Wisconsin

The comparison of the material cost and compressive strength of self-compacting concrete mixtures in the previous section showed that there are at least two options of using by-products beneficially in producing self-compacting- concrete:

1. Replacement of up to 50% of natural sand with quarry fines saved the material cost

without affecting the early-age and late-age strength of concrete.

2. Replacement of up to 35% of cement with Class C fly ash saved the material cost and

improved the long-term strength of concrete, while maintaining a relatively high level of

3-day compressive strength.

Based on this observation, the potential material-cost savings in Wisconsin due to the use of quarry fines and Class C fly ash in self-compacting concrete are estimated in this section.

In this study, it was assumed that about 400,000 yd3 of self-compacting concrete

(SCC) could potentially be produced in Wisconsin yearly (Table 43).

Table 43. Annual Consumption of Cement and Estimated Annual Production of Cement-Based Materials in Wisconsin

Products Quantity Cement Used (tons/year) 2,000,000 Cement Used (lb/year) 4,000,000,000 Cement Used (lb/yd3 of cement-based material) 500 Cement-Based Materials Produced (yd 3/year) 8,000,000 SCC Among Cement-Based Materials, Assumed (%) 5 SCC Expected to be Produced, Assumed (yd3/year) 400,000 SCC Expected to be Produced, Assumed (million yd3/year) 0.4

Table 44 presents the potential savings in the cost of materials used in self- compacting concrete (SCC) in Wisconsin. For example, if 25% of the SCC produced in

Wisconsin was made by replacing 35% of cement with Class C fly ash combined with 50% replacement of sand with quarry fines (Mixture 27), and another 25% of SCC was produced with 35% of cement replaced with Class C fly ash (Mixture 18), then the combined potential savings in material cost would be about $5 million per year (Table 44). This is about a 16% savings compared with the material cost of using neither Class C fly ash nor quarry fines

(Mixture 15R [Control]) in any of the self-compacting concrete produced in Wisconsin ($32 million/year).

Table 44. Potential Use of Class C Fly Ash and Quarry Fines in Self-Compacting Concrete and Material-Cost Savings in Wisconsin

Mixture No. 15R 18 27 Total (Control) (Ref.) % Replacement of Cement with Class C 0 35 35 … Fly Ash % Replacement of Sand with Quarry 0 0 50 … Fines Nominal Material Cost ($/yd 3) 80 60 50 … Nominal Savings in Material Cost ($/yd3) 0 20 30 … Market Share (% of total SCC) 100 0 0 100 Production (million yd3/year) 0.4 0 0 0.4 Material Cost (million $/year) 32 0 0 32 Savings in Material Cost (million $/year) 0 0 0 0 Market Share (% of total SCC) 50 50 0 100 Production (million yd3/year) 0.2 0.2 0 0.4 Material Cost (million $/year) 16 12 0 28 Savings in Material Cost (million $/year) 0 4 0 4 Market Share (% of total SCC) 50 25 25 100 Production (million yd3/year) 0.2 0.1 0.1 0.4 Material Cost (million $/year) 16 6 5 27 Savings in Material Cost (million $/year) 0 2 3 5

The total cost of the materials used in self-compacting concrete (SCC) can vary depending upon the quantity of SCC made with Cass C fly ash and quarry fines (Table 45).

The resulting material-cost savings are presented in Table 46.

If 100% of the SCC produced in Wisconsin was made by replacing 35% of cement with Class C fly ash, the total cost of materials used in SCC would decrease from about $32 million/year to $24 million/year, resulting in the savings of $8 million/year (25%).

If 100% of the SCC produced in Wisconsin was made with 35% replacement of cement with Class C fly ash, combined with 50% replacement of sand with quarry fines, then the total material-cost would decrease from about $32 million/year to $20 million/year, with a savings of $12 million/year (38%).

Table 45. Estimated Total Cost of Materials Used in Self-Compacting Concrete (SCC) in Wisconsin as Influenced by the Market Share of SCC Containing Class C Fly Ash and Quarry Fines

Market Share of SCC Estimated Total Material-Cost (million $/year) Made with Fly Ash Market Share of SCC Made with Fly Ash* and Quarry Fines† (% of total SCC) (% of total SCC) 0 25 50 75 100 0 32 30 28 26 24 25 29 27 25 23 … 50 26 24 22 … … 75 23 21 … … … 100 20 … … … …

† SCC made with 35% replacement of cement with Class C fly ash combined with 50% replacement of sand with quarry fines (Mixture 27). * SCC made with 35% replacement of cement with Class C fly ash (Mixture 18).

Table 46. Potential Savings in the Cost of Materials Used in Self-Compacting Concrete (SCC) in Wisconsin with the Use of Class C Fly Ash and Quarry Fines

Market Share of SCC Potential Savings in Material Cost (million $/year) Made with Fly Ash Market Share of SCC Made with Fly Ash* and Quarry Fines† (% of total SCC) (% of total SCC) 0 25 50 75 100 0 0 2 4 6 8 25 3 5 7 9 … 50 6 8 10 … … 75 9 11 … … … 100 12 … … … …

SUMMARY AND CONCLUSIONS

Based on the extensive laboratory work, it was concluded that the limestone-quarry fines and Class C fly ash have high potential for utilization in the manufacturing of self- compacting concrete (SCC). The test data collected indicate that these materials can be used in the manufacturing of economical SCC in different ways. When the quarry fines and fly ash were used as partial replacements of sand and cement, respectively, the requirements of expensive chemicals such as HRWRA and VMA decreased.

By using quarry fines for the replacement of up to 50% of sand by mass, high- strength SCC with the 28-day compressive strength in the range of 7630 psi and 9150 psi was produced.

Partial replacement of the fly ash with the limestone-quarry fines did not result in any appreciable economical benefits.

By using the Class C fly ash for the replacement of up to 55% of cement by mass, high-strength SCC with the 28-day compressive strength in the range of 6900 psi and 10,200 psi was produced.

Foundry baghouse dust material could be used for the partial replacement of fly ash and sand in a SCC without affecting the requirements of chemical admixtures. But the replacement level might be less than 10% by mass of fly ash. The use of foundry dust drastically increased air content of the concrete, probably due to the high organics-content of the foundry dust.

General conclusions based on the laboratory investigation are as presented below:

1. Replacement of up to 50% of sand with the limestone-quarry fines resulted in:

(a) Some reductions in required amount of HRWRA and little changes in U-flow test

results; and

(b) Either some increase, or at times decrease, in compressive strength.

2. Replacement of up to 50% of Class C fly ash with limestone-quarry fines resulted in:

(a) Little reduction or some increase in required amount of HRWRA, and somewhat

lower performance in slump-flow and U-flow tests; and

(b) Little changes in the 3-day strength and considerable reduction in the 28-day

strength.

3. Replacement of up to 30% of the Class C fly ash combined with replacement of up to 6%

of sand with limestone-quarry fines resulted in:

(a) Little reduction or some increase in required amount of HRWRA at the same level of

slump-flow; and

(b) Slight reduction in the 3-day strength and considerable reduction in the 28-day

strength.

4. Replacement of a part of cement with the Class C fly ash resulted in:

(a) Large reductions in required amounts of chemical admixtures (HRWRA and VMA)

and considerable improvement in U-flow test results at the same level of slump-flow;

(b) Some reduction in the 3-day compressive strength and some increases in the 28-day

compressive strength for 20% and 35% replacements of cement;

45% replacement of cement; and

(d) Large reductions in the 3-day and 7-day strengths and some reduction in the 28-day

strength for 55% replacements of cement.

5. Replacement of up to 30% of the Class C fly ash combined with replacement of up to 6%

of sand with the iron-foundry baghouse dust resulted in:

(a) Considerable increase in required amount of HRWRA and slight decrease in required

amount of VMA, at the same level of slump-flow;

(b) Very high air content probably due to interaction between the high-organics content

in foundry baghouse dust and at least one of the particular brands of chemical

admixtures (HRWRA and VMA) used; and,

strength due to reduced amount of fly ash and high air-content of SCC.

6. In summary, based on the chemical-admixture demands and strength of self-compacting

concrete, it was observed:

(a) Partial replacement of sand with limestone-quarry fines appears to be economically

beneficial, without affecting the strength of concrete;

(b) Partial replacement of Class C fly ash with limestone-quarry fines increases the

material cost slightly and decreases the long-term strength of concrete;

with limestone-quarry fines does not affect the material cost, but decreases the long-

term strength of concrete;

(d) Use of the Class C fly ash as a partial replacement of cement appears to be very

beneficial to the economy and the long-term strength gain of concrete; and,

(e) Partial replacement of Class C fly ash, combined with partial replacement of sand,

with foundry baghouse dust increases the material cost and decreases both the early-

age strength and the long-term strength of concrete.

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15. Skarendahl, Å.; and Petersson, Ö., “Self-Compacting Concrete,” State-of-the-Art Report of RILEM Technical Committee 174-SCC Self-Compacting Concrete, Å. Skarendahl and Ö. Petersson, Eds., RILEM Publications S. A. R. L., Cachan Cedex, France, 2001, pp. 25-39.

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17. Nagataki, S.; and Fujiwara, H., “Self-Compacting Property of Highly-Flowable Concrete,” Proceedings, Second CANMET/ACI International Symposium on Advances in Concrete Technology, SP-154, V. M. Malhotra, Ed., American Concrete Institute, Farmington Hills, Michigan, 1995, pp. 301-314.

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30. Westerholm, M.; Skoglund, P.; and Trägårdh, J., “Chloride Transport and Related Microstructure of Self-Consolidating Concrete,” Proceedings, First North American Conference on the Design and Use of Self-Consolidating Concrete, Northwestern University, Evanston, Illinois, USA, November 2002, pp. 355-361.

31. Audenaert, K.; Boel, V.; and De Schutter, G., “Durability of Self-Compacting Concrete,” Proceedings, First North American Conference on the Design and Use of Self-Consolidating Concrete, Northwestern University, Evanston, Illinois, USA, November 2002, pp. 377-383.

32. Raghavan, K. P.; Sharma, B. S.; and Chattopadhyay, D., “Creep, Shrinkage and Chloride Permeability Properties of Self-Consolidating Concrete,” Proceedings, First North American Conference on the Design and Use of Self-Consolidating Concrete, Northwestern University, Evanston, Illinois, USA, November 2002, pp. 341-347.

33. Turcry, P.; Loukili, A.; and Haidar, K., “Mechanical Properties, Plastic Shrinkage and Free Deformations of Self-Consolidating Concrete,” Proceedings, First North

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34. Petersson, O., “Limestone Powder as Filler in Self-Compacting Concrete - Frost Resistance, Compressive Strength and Chloride Diffusivity,” Proceedings First North American Conference on the Design and Use of Self-Consolidating Concrete, Northwestern University, Evanston, Illinois, USA, November 2002, pp. 391-396.

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APPENDIX: TEST METHODS FOR THE EVALUATION OF SELF- COMPACTABILITY OF FRESH CONCRETE

Slump-Flow Test

The slump-flow test is the simplest and most commonly adopted test method for evaluating self-compactability quality of SCC. A slump cone is filled with concrete without any tampering. The cone is lifted, and the diameter of the concrete is measured after the flow has stopped (Fig. 17).

Fig. 17. Slump-flow test

The mean diameter in two perpendicular directions of the concrete spread is taken as the slump-flow. SCC is characterized by a slump-flow of 650 to 800 mm (26 to 31.5 in.)

[18]. The slump-flow test judges the capability of concrete to deform under its own weight against the friction on the surface of the base plate with no other external resistance present

[8, 15, 16, 18]. The measurement of slump-flow indicates the flowability of SCC and determines the consistency and cohesiveness of the concrete [3]. At a large slump-flow, the concrete might segregate, and at a small slump-flow the concrete might have insufficient flow to pass through highly congested reinforcement [17]. The slump-flow test can give an indication of filling ability and susceptibility to segregation of the SCC [16]. The passing ability of concrete is not indicated by this test. Flowing time from the initial diameter of 200 mm to 500 mm, i.e. T50cm, is sometimes used for a secondary indication of flow. A time of

3-7 seconds is acceptable for structural engineering applications and 2-5 seconds for housing applications [15, 18]. However, this test is not sensitive enough to distinguish between SCC mixtures and superplasticized concrete.

U-Flow Test

The U-flow test examines the behavior of the concrete in a simulated field condition

[20]. It is the most widely adopted test method for characterization of SCC. The U-flow test simulates the flow of concrete through an obstruction of reinforcing steel. This test is considered more appropriate for characterizing the self-compactability of concrete [1, 3]. In the U-flow test, the degree of compactability can be indicated by the height that the concrete reaches after flowing through an obstacle (Fig. 18). This test is performed by first completely filling the left chamber of the U-flow device, while the sliding door between the two chambers is closed. The door is then opened, and the concrete flows through the rebars into the right-side chamber. The SCC should flow to about the same height in the two chambers. If the filling height is at least 70% of the maximum height possible, then the concrete is considered self-compacting. The selection of this percentage is arbitrary and a higher value might be considered more conservative. In the U-flow device, having the

dimensions as shown in Fig. 18, the maximum filling height is 300 mm (11.8 in.), a little more than half of the height of the U-flow apparatus. The maximum depth measured from the top of the apparatus to the top of concrete in the first chamber after concrete flowed is about 270 mm (10.6 in.). The U-flow test measures filling, passing, and segregation properties of SCC, including moving past the congested reinforcement area.

Fig. 18. U-flow test [14]

V-Flow Test

Another type of test, which is frequently adopted, is the V-flow test. It consists of a funnel with a rectangular cross section. The top dimension is 495 mm by 75 mm and the bottom opening is 75 mm by 75 mm. The total height is 572 mm with a 150 mm long straight section. The SCC is poured into the funnel with a gate blocking the bottom opening.

When the funnel is completely filled, the bottom gate is opened and the time it takes for the

concrete to flow out the funnel is noted. This is called the V-flow time [20]. A flow time of less than 6 seconds is recommended for a concrete to qualify for SCC.

L-Box Test

The L-box test method uses a test apparatus consisting of a vertical section and a horizontal section (Fig. 19).

Fig. 19. L-box apparatus [21]

Reinforcing bars are placed at the intersection of the two areas of the apparatus. The vertical part of the box is filled with 12.7 L (approximately 0.45 ft3) of concrete and then left to rest for one minute, in order to allow any segregation to occur. The gap between the reinforcing bars is generally kept 35 and 55 mm for 10 and 20 mm maximum-size coarse aggregates, respectively. The time taken by the concrete to flow a distance of 200 mm (T-

20) and 400 mm (T-40) in the horizontal section of apparatus, after the opening of the gate from the vertical section, is measured. The heights of concrete at both ends of the apparatus

(H1 and H2) are also measured to determine L-box results. This test gives an indication of the filling, passing, and segregation-resisting ability of the concrete [8].

J-Ring Test

The J-ring test is another test method for the study of the blocking behavior of SCC.

The apparatus consists of rebars surrounding the standard slump cone in a slump-flow test

(Fig. 20). The spacing between the rebars is generally kept three times the maximum size of the aggregate for normal reinforcement consideration [16, 18]. The concrete flows between the rebars after the cone is lifted and thus the blocking behavior/passing ability of SCC can be detected.

Fig. 20. J-ring test apparatus [23]

From the published literature reviewed, a wide variation in the methods discussed here can be observed for evaluating self-compacting characteristics of concrete. Ferraris [22] reported that a concrete mixture could qualify for self-compactability based on slump-flow

but could fail on the basis of V-flow or U-flow test results. Similar results are also reported by Bouzoubaâ and Lachemi [11] for slump-flow and V-flow tests.