S.Subash Raja* et al. /International Journal of Pharmacy & Technology
ISSN: 0975-766X CODEN: IJPTFI Available Online through Research Article www.ijptonline.com EXPERIMENTAL STUDY OF SELF CURING AND SELF COMPACTION – BY USING RECRON FIBER AND POLYETHYLENE GLYCOL 400 IN REINFORCED CONCRETE S.Subash Raja* Research Scholar, Civil Engineering Department, Bharath Institute of Higher Education and Research, Bharath University, Chennai. Email: [email protected] Received on: 15.10.2016 Accepted on: 22.11.2016 Abstract
Concrete curing is one of the most important processes in achieving the desired properties of the concrete. Self curing concrete would be able to cure on its own without having to provide additional water. An attempt has been made in this study to provide the advantages and benefits of using fibre reinforced concrete. In this experimental study, the properties of self-curing recronfibre reinforced Concrete were studied. Three different concrete grades were considered for the study namely M20, M25 and M30. For each Grade of concrete, four different types of specimens were casted.
Experimental result shows that Strength of Self Curing Concrete is reduced by 10% when compared with water curing concrete. At the same time, the strength of recron Fiber concrete is increased by 25% when compared with normal concrete.
Introduction
Concrete curing is one of the most important processes in achieving the desired properties of the concrete. The test cubes of any particular mix will be immersed in water till the day of testing. This is done in order to promote the hydration process of the concrete. The initial mixing water used to make concrete will not be sufficient to bring out the full performance of the concrete. However, the actual structures cannot be immersed in water. That is why the structures shall be covered with wet gunny sack or plastic sheet. The reason being that either we provide water (from gunny sack) to promote continuous hydration or we protect the initial water from evaporating. Then again, this is not as easy as it sounds. It is not widely practiced in construction industry (except in much regulated countries). This is one of the main reasons why the concrete structure does not last throughout the design life (or at least half of it). Therefore, now it is time to think of a way to cure the concrete from inside without having to cover it with gunny sack or plastic sheet. This new
IJPT| Sep-2016 | Vol. 8 | Issue No.4 | 23357-23364 Page 23357 S.Subash Raja* et al. /International Journal of Pharmacy & Technology technology is called self-curing concrete. As it name sounds, the concrete would be able to cure on its own without having to provide additional water. This concept is also known internal curing. The basic concept of this technology is to provide water for concrete, so that it can continue the curing process on its own. This is done by embedding the water inside the materials used to make concrete. If the water just added as mixing water; this would lead to many other quality related problems, such as bleeding, segregation, and etc. Therefore, a special material shall be used; so that some of the water can be hidden into the material. This water will be released into the concrete over time after the concrete has been placed in the structure and hardened. By doing this the hardened concrete will be able to undergo continuous curing for a long time, which will promote towards a better hydration product. There are many types of material that can be used to impregnate the water. One example is by using feldspar; which is capable of hiding the water into its porous microstructure. The water impregnated feldspar can be used to replace part of sand for the concrete mix. One disadvantages of feldspar is the cost, which is much higher than the normal sand.The use of fibers to reinforced concrete materials is a well–known concept. It has been practiced since ancient times, with straw mixed into mud bricks and horsehair included in mortars. However, in our modern day construction practices we have forgotten the ancient practices to control cracks in concrete. Concrete cracking is normal. Portland cement concrete is considered to be a relatively brittle material and is prone to crack in the plastic as well as the hardened stage. Plastic shrinkage occurs when the evaporation of water from the surface of concrete is greater than the rising bleed water. As concrete is very weak in tension in its plastic stage, a volume change causes the surface to crack. As it hardens, the water present in the pores of concrete begins to evaporate. This causes the concrete to shrink due to the volume change, which is restrained by the sub-grade and reinforcement. This results in a tensile stress being developed in hardened concrete, again causing the concrete to crack. Cracks lead to negative perception of quality, durability and serviceability, however in most cases they become only aesthetic problems. Cracks also results in disputes between the owner, Architect, design Engineer and contractor which results in job delays and cost increases due to work stoppages and evaluation which is more severe than the actual consequences of cracking. One of the solutions to this problem is the additions of fibers to concrete. An attempt has been made in this study to provide the advantages and benefits of using fiber reinforced concrete for a variety of applications. The use of fibers help in modifying properties of concrete both in plastic and hardened stage and thus results into a more durable concrete. Incorporating Synthetic fibers help to reduce thermal and shrinkage cracks.
IJPT| Sep-2016 | Vol. 8 | Issue No.4 | 23357-23364 Page 23358 S.Subash Raja* et al. /International Journal of Pharmacy & Technology Addition of steel fibers enhances the ductility performance, post-crack tensile strength, fatigue strength and impact strength of concrete structures.FRC is Portland cement concrete reinforced with more or less randomly distributed fibers.
In FRC, thousands of small fibers are dispersed and distributed randomly in the concrete during mixing, thus improving concrete properties in all directions. Fibers help to improve the pre- crack tensile strength, post peak ductility performance, fatigue strength, impact strength and minimize thermal and shrinkage cracks. A wide variety of fibers have been used in concrete. For each application it needs to be determined which type of fiber is optimal in satisfying the concrete application.
The different types of fibers used as concrete reinforcement are synthetic fibers and steel fibers. The different types of synthetic fibers used are Polypropylene, Nylon, Polythene, Polyester and Glass Fibers. For architectural and decorative concrete products and for prevention of early age cracking, synthetic fibers may be used. Steel fibers are used for applications where properties of concrete in the hardened stage have to be modified, namely, post crack flexural strength, abrasion resistance, impact resistance and shatter resistance of concrete.
Application of Recron Fiber
RCC and PCC like lintel, beam, column, flooring and wall plastering.
Foundation, tanks, manhole cover and tiles.
Plastering.
Roads and Pavement.
Hollow Blocks and Precast Slabs.
Wherever cement is used, the Recron can be used to improve the quality of construction.
Advantages of Recron Fiber
It result savings of Expansive mortar, cement and sand.
Time taken for plastering is reduced.
Work will complete faster.
Reduce cracks during plastic and hardening stage.
Reduce water seepage.
It protect steel in concrete from corroding.
IJPT| Sep-2016 | Vol. 8 | Issue No.4 | 23357-23364 Page 23359 S.Subash Raja* et al. /International Journal of Pharmacy & Technology It protect walls from damping.
Specifications of Recron 3s
Property Value
Cut length : 6 mm or 12 mm
Melting point > 250 C
Chemical to Achieve Self-Curing
The water-soluble chemical added during the mixing can reduce water evaporation from and within the set concrete, making it „self-curing.
The chemical should have abilities to reduce evaporation from solution and to improve water retention in ordinary
Portland cement.
Autogenous Shrinkage
It is as a volume change in concrete occurring without moisture transfer from the environment into concrete.It is due to the internal chemical and structural reactions of the concrete.
Improvements to Concrete due to Internal Curing
Reduces autogenous cracking
largely eliminates autogenous shrinkage
Reduces permeability
Protects reinforcing steel
Mix Design Report
Cement : OPC – 53 S Grade for use in concrete.
Source : Dalmia cement (P) Ltd, Dalmaiapuram, Tiruchirapalli.
Coarse aggregate : conforming to IS 383 – 1970
Max size of coarse aggregate : 20 mm
Source & Type : Locally available broken blue granite
Shape and Texture : Angular rough grained
Fine aggregate : conforming to IS 383 -1970
IJPT| Sep-2016 | Vol. 8 | Issue No.4 | 23357-23364 Page 23360 S.Subash Raja* et al. /International Journal of Pharmacy & Technology Source & Type : locally available nature river sand
Shape and Texture : Clean and dirty
Water : Conforming to IS 456 Cl 4.3
Source : Bore well
Concrete Mix design : As per IS Specifications
Mix Design for M20 Grade concrete
Cement used : Dalmia OPC – 53Grade
Specific gravity of cement : 3.15
Specific gravity of coarse aggregate 20 mm: 2.7
Specific gravity of fine aggregate : 2.64
Water Cement Fine Aggregate Coarse Aggregate
191.58 383.16 590.06 1195.46
0.5 1 1.54 3.12
Mix proportion for M20 is 1: 1.54: 3.12
Similarly for M25 and M30
Mix proportion for M25 is 1:1.21:2.48
Mix proportion for M30 is 1: 1.02: 2.06
Casting of Concrete Specimens
The types of mixes adopted in this work are mentioned below,
For Each grade of concrete,
Type1: Ordinary concrete(water curing)
Type2: Concrete with curing compound
Type3: Concrete with Recron fibres
Type4: Concrete with Recron fibres and curing compound
Dosage of Curing Compound
It was added to the water in the proportion of 2% of water and thoroughly mixed.
Addition of Fiber to the Concrete
IJPT| Sep-2016 | Vol. 8 | Issue No.4 | 23357-23364 Page 23361 S.Subash Raja* et al. /International Journal of Pharmacy & Technology 125gm of Recron fiber is added with the concrete for one Bag of cement.
Experimental Results
7th day Compressive Strength of M20 Grade Concrete
Type 1 Type 2 Type 3 Type 4 M20 (N/mm2) (N/mm2) (N/mm2) (N/mm2) 1 21.44 18.76 25.88 23.66 2 21.66 18.88 25.66 23.76 3 21.22 19.00 25.44 23.56 Average 21.44 18.88 25.66 23.66
7th day Compressive Strength of M25 Grade Concrete
Type 1 Type 2 Type 3 Type 4 M25 (N/mm2) (N/mm2) (N/mm2) (N/mm2)
1 27.00 24.66 30.44 27.22 2 26.88 24.22 30.66 27.88 3 26.76 23.78 30.22 27.88 Average 26.88 24.22 30.44 27.66
7th day Compressive Strength of M30 Grade Concrete
Type 1 Type 2 Type 3 Type 4 M30 (N/mm2) (N/mm2) (N/mm2) (N/mm2) 1 31.44 29.88 35.22 33.44 2 31.22 29.88 35.66 33.44 3 31.00 29.22 35.44 32.78 Average 31.22 29.66 35.44 33.22
7th day Compressive Strength of Concrete cubes
Grade of Type 1 Type 2 Type 3 Type 4 concrete (N/mm2) (N/mm2) (N/mm2) (N/mm2) M20 21.44 18.88 25.66 23.66 M25 26.88 24.22 30.44 27.66 M30 31.22 29.66 35.44 33.22
7th day Compressive Strength of Concrete cubes
IJPT| Sep-2016 | Vol. 8 | Issue No.4 | 23357-23364 Page 23362 S.Subash Raja* et al. /International Journal of Pharmacy & Technology 28th day Compressive Strength of M20 Grade Concrete
Type 1 Type 2 Type 3 Type 4 M20 (N/mm2) (N/mm2) (N/mm2) (N/mm2) 1 32.22 29.11 38.44 35.11 2 31.44 28.44 38.22 34.88 3 31.88 28.22 38.66 34.22 Average 31.85 28.59 38.44 34.74
28th day Compressive Strength of M25 Grade Concrete
Type 1 Type 2 Type 3 Type 4 M25 (N/mm2) (N/mm2) (N/mm2) (N/mm2) 1 36.88 34.22 43.00 39.22 2 37.00 34.88 43.11 39.88 3 36.44 34.66 43.44 39.33 Average 36.77 34.58 43.18 39.48
28th day Compressive Strength of M30 Grade Concrete
Type 1 Type 2 Type 3 Type 4 M30 (N/mm2) (N/mm2) (N/mm2) (N/mm2) 1 42.11 38.33 51.11 45.66 2 41.88 38.11 50.88 45.11 3 41.44 38.11 51.66 46.00 Average 41.81 38.18 51.21 45.59
28th day Compressive Strength of Concrete cubes
Grade of Type 1 Type 2 Type 3 Type 4 concrete (N/mm2) (N/mm2) (N/mm2) (N/mm2)
M20 31.85 28.59 38.44 34.74
M25 36.77 34.58 43.18 39.48 M30 41.81 38.18 51.21 45.59
28th day Compressive Strength of Concrete cubes
IJPT| Sep-2016 | Vol. 8 | Issue No.4 | 23357-23364 Page 23363 S.Subash Raja* et al. /International Journal of Pharmacy & Technology Conclusions
In this experimental study, the properties of concrete were studied for three different grades of concrete M20, M25,
and M30.
For each grade of concrete, four different types of concrete specimens were casted and the properties were studied.
More number of concrete cubes was casted to study the 7th and 28th day compressive strength properties of concrete.
Experimental result shows that Strength of Self Curing Concrete is reduced by 10% when compared with water
curing concrete. At the same time, the strength of Recron Fiber concrete is increased by 25% when compared with
normal concrete.
References
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35-40, 2005.
3. Kewalramani, M.A.; Gupta, R, “Experimental study of concrete strength through an eco-friendly curing technique,”
4. Advances in concrete technology and concrete structures for the future. Dec 18-19, 2003. Annamalainagar.
5. IS: 383-1963, Specifications for Coarse and Fine Aggregate from Natural Sources for Concrete, Bureau of Indian
Standards, New Delhi.
6. IS:456-2000, Plain and Reinforced Concrete- Code of Practice,Bureau of Indian Standards, New Delhi, 2000
7. IS:10262-1982, Recommended Guide Lines for Concrete Mix Design, Bureau of Indian Standards, New Delhi.
8. Shetty M.S., Concrete Technology - Theory and Practice, S. Chand & Company P. Ltd., New Delhi, 2005
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Concrete with Fibres Of Different Origins, The Indian Concrete Journal, 81,17- 23.
10. IS:12269-1987, Specification for 53 Grade Ordinary Portland Cement, Bureau of Indian Standards, New Delhi.
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