Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1958 The pozzolanic activity of certain fly ashes and soil minerals Roy Junior Leonard Iowa State College Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Engineering Commons Recommended Citation Leonard, Roy Junior, "The pozzolanic activity of certain fly ashes and soil minerals " (1958). Retrospective Theses and Dissertations. 1634. https://lib.dr.iastate.edu/rtd/1634 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. THE POZZOLMIG ACTIVITY OP CERTAIN PLY ASHES MD SOIL MINERALS by Roy Junior Leonard A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY Major Subjects Soil Engineering Approved; Signature was redacted for privacy. In Charge of Major Work Signature was redacted for privacy. Signature was redacted for privacy. Déan"of Graduate College Iowa State College 1958 îi TABLE OP CONTENTS Page INTRODUCTION 1 LITERATURE REVIEW $ Early Investigations 5 Theories of Pozzolania Reaction Mechanism 6 Factors Influencing the Poszolanic Reaction 7 Temperature 7 Nature of the pozzolan 9 Surface area 10 Carbon content 11 Alkali and sulfate content 12 Carbon dioxide 12 Hydrogen ion concentration Lime factors Moisture % Time îi Poszolanic Reaction Products 18 A Siliceous reaction products 19 Aluminous reaction products 21 Quaternary reaction products 23 Secondary reaction products 23 Methods for Evaluating Pozzolans 21}. Physical tests 25 Compressive strength tests 25 Time of set tests 27 Chemical tests 27 Chemical analysis 27 Solubility tests 28 Pétrographie» x-ray diffraction and differential thermal analysis 29 Free calcium hydroxide determinations 30 Insoluble residue methods 32 Lime absorption rate method 32 MATERIALS 3I4. Fly Ashes Used 3I4. Selection factors 34. Description of fly ashes 3k Sample No© 10 35 ill TABLE OF CONTENTS (Continued) Page Sample No« 11 35 Sample No* 12 35 Sample No0 13 35 Sample No* llj. 36 Sample No® 1> 36 Physical properties of the fly ashes 36 Chemical properties of the fly ashes 39 Mineral Samples Used ij.0 Limes Used ijjL LABORATORY METHODS i|2 Solubility Tests 1*2 Absorption Test Methods lj.3 Titration Tests 48 Soluble Silica in Solution J4.9 pH Measurements 49 Tests for Reaction Products 50a Pétrographie analysis 50a X-ray diffraction 50a Differential thermal analysis 50b DISCUSSION OP RESULTS 51 Investigation of the Ply Ashes 51 Chemical specifications 51 Solubility tests 52 Compressive strength 53 Lime absorption 55 Influence of temperature 59 Influence of temperature on lime absorption 62 Influence of particle sis© on the reaction 7I4. Influence of concentration on the reaction 80 Influence of concentration on strength 86 pH and silica in solution 87 Investigation of the Non=Clay Minerals 90 Lime absorption by the minerals 91 Influence of concentration on the reactions 101 pH and soluble silica in solution 101 CalciumîMagnesium Ratio Tests 107 Absorption tests 107 Strength studies of CasMg lime mortars 108 pH and soluble silica in solution lllj. iv TABLE OP CONTENTS (Continued) Reaction Products 116 Optical observations 118 X-ray diffraction results 118 Differential thermal analysis 123 Factors and Mechanism of the Reaction 126 Suggested Research 133b SUMMARY AND CONCLUSIONS I3I4. REFERENCES 139 ACKNOWLEDGMENT 3.44 V LIST OF TABLES Table Page 1 Uo Se Bureau of Reclamation specifications for fly ash (47) 28 2 Proposed ASTM chemical requirements for fly ash (2) 29 3 Physical properties of fly ashes 37 4 Chemical properties of fly ashes used 39 5 Properties of minerals used I4.O 6 Per cent reduction in alkalinity of the fly ashes 52 7 Influence of particle size on loss on ignition 80 8 Increase in Ca(0H)g absorption at 45 days due to decreasing the sample weight 50 per cent 85 9 Per cent increase in compressive strength at the end of various test periods due to increasing Ca(0H)p content from 2 to li per cent at 20° and 60 Co (23) 86 10 Per cent increase in compressive strength at the end of various test periods due to increasing Ca(0H)o content from II to 8 per cent at 20° and 60 Co (23) 87 11 pH measurements of filtered fly ash solutions after 15* 30» 45 and 365 day test periods at 20° C. 88 12 pH measurements of filtered fly ash solutions after 15 and 45 day test periods at 20°« 40°* 60° and 80° 0o 89 13 Soluble silica in solution. ppm« at the end of 45 day test periods for 20"9 4-0 9 60° and 80° 0o reaction temperatures 90 vi LIST OP TABLES (Continued) Table Page 14 pH measurements of filtered 1 gnu mineral sample solutions for 15$ 30, 45 and 60 day test periods at 20°, 40°s 60° and 80° C. 105 15 p p m of soluble silica in filtered 1 gm0 mineral sample solutions for 15» 30» 45 and 60 day test periods at 20°, 4° » 60° and 80° C« 106 16 GasMg ratios of solutions at the end of various absorption test periods at various temperatures 109 17 Mg(0H)2 concentrations of solutions at the end of various test periods at various temperatures 110 18 Per cent increase in strength of fly ashes 10 and 11 with Q% CasMg admixture due to increasing the temperature from 20 to 40 C® (50) 112 19 Influence of the amount of CarMg ratio admixture on the compressive strength of fly ashes 10 and 11 at 20° C„ (50) 114 20 pH of GasMg solutions at the end of various absorption test periods (1/2 gnu samples) 115 21 Soluble silica in CarMg ratio solutions at the end of various absorption test periods (1/2 gm, samples) 117 22 Powder x-ray data for calcium silicate hydrate I (40) 121 23 Diffusion constants for fly ash samples 131 24 Diffusion constants for mineral samples 133a vil LIST OP FIGURES Figure Page 1 Typical conditions of formation for compounds in the CaO-SiOg-HgO system (7)o 22 2 Photomicrographs of fly ashes used in this study* 35b 3 Absorption test apparatus in position for testing* I4J4. 4 Compressive strengths of four fly ash mortars with 8# Ca(0H)2 cured at 20° Co (18)0 54 5 Absorption of calcium by fly ash samples 109 11 and 12 at 20 C over a one year period,, 56 6 Absorption of calcium by fly ash samples 13$ 14 and 15 at 20° C over a one year period® 57 7 Compressive strengths of four fly ash mortars with 8% Ca(0H)g cured at 60° C (18)e 60 8 Percent increase in compressive strength with time due to a h.0°G increase in curing tempera® tiure (20 G to 60°C) (18)0 61 9 Absorption of calcium at 20°C by fly ash samples 10s 11 and 12 (3 gm samples) 0 63 10 Absorption of calcium at 20°C by fly ash samples 13* l4 and 15 (3 gm samples) » 63 11 Absorption of calcium at 40°C by fly ash samples 105 11 and 12 (3 gm samples) e 64 12 Absolution of calcium at l\.0°C by fly ash samples 13a llj- and 15 (3 saisies) e 64 13 Absorption of calcium at 60°C by fly ash samples 10g 11 and 12 (3 gm samples) 0 66 14 Absorption of calcium at 60°C by fly ash samples 13s 2-4 and 15 (3 g® samples) 0 66 viii LIST OF FIGURES (Continued) Figure Page 15 Absorption of calcium at 80° C by fly ash sample 10# 11 and 12 (3 gm samples)0 68 16 Absorption of calcium at 80° C by fly ash samples 13» 14 and 15 (3 gm samples)* 68 17 Percent calcium absorption by fly ash sample 10 at 20° 9 40°, 60° and 80°Co 69 18 Percent calcium absorption by fly ash sample 11 at 20°CS 40°C9 60°C and 80°C* 69 19 Percent calcium.absorption by fly ash sample 12 at 20 3 40 , 60 and 80°C® 70 20 Percent calcium.absorption by fly ash sample 13 at 20 , 40°, 60° and 80°C« 70 21 Percent calcium.absorption by fly ash sample 14 at 20°, 40°, 60° and 80°Ce 71 22 Percent calcium absorption by fly ash sample 15 at 20°, 40°» 60° and 80°C. 71 23 Effect of temperature on time required for 1/2 of Ca(0H)g to be absorbed® 73 24 Influence of grain size of fly ash sample 10 on calcium absorption at 20°Co 76 25 Influence of grain size of fly ash sample 11 on calcium absorption at 20°C® 76 26 Influence of grain size of fly ash sample 10 on calcium absorption at 40°C© 77 27 Influence of grain size of fly ash sample 11 on calcium absorption at 4° Cc 77 28 Influence of grain size of fly ash sample 10 on calcium absorption at 60°C© 78 29 Influence of grain size of fly ash sample 11 on calcium absorption at 60°Co 78 ix LIST OP FIGURES (Continued) Figure Page 30 Influence of grain size of fly ash sample 10 on calcium absorption at 80°C© 79 31 Influence of grain size of fly ash sample 11 on calcium absorption at 80°Co 79 32 Absorption of calcium by fly ash samples 10, 11 and 12 at 20°C (1 l/2 gm samples)« 8l 33 Absorption of calcium by fly ash samples 13, 14 and 15 at 20 C (1 1/2 gm samples)® 8l 34 Absorption of calcium by fly ash samples 10, 11 G and 12 at 40° « (1 l/2 gm samples)e 82b 35 Absorption of calcium by fly ash samples 13, 14 and 15 at 40 0» (1 1/2 gm samples)„ 82b 36 Absorption of calcium by fly ash samples 10, 11 and 12 at 60° C6 (1 l/2 gm samples)» 83b 37 Absorption of calcium by fly ash samples 13, 14 and 15 at 60° C© (1 1/2 gm samples)® 83b 38 Absorption of calcium by fly ash samples 10, 11 and 12 at 80°C (1 1/2 gm samples)@ 84 39 Absorption of calcium by fly ash samples 13, 14 and 15 at 80°C (1 1/2 gm samples)• 84 40 Absorption of calcium by mineral samples at 20°C (1 gm samples) 0 92 41 Absorption of calcium by mineral samples at 40°C (1 gm samples)o 92 42 Absorption of calcium by mineral samples at 60°C (1 gm samples) «, 93 43 Absorption of calcium by mineral samples at 80°C (1 gm samples) «, 94 44 Percent calcium absorption by quarts at 20° 9 40° 60° and 80°Ca 96 X LIST OF FIGURES (Continued) Figure Page kS Percent calcium absorption by albite at 20°$ 40 9 60° and 80°Co 97 46 Percent.calcium absorption by an desine at 20°« 40°, 60° and 80°C.