FACTORS INFLUENCING COMPRESSIVE STRENGTH OF GEOPOLYMER CONCRETE

To study effects of several factors on the properti es of fly ash based geopolymer concrete on the comp ressive strength and also the cost comparison with the normal concrete. The test variables were molarities of sodium hydroxide(NaOH) 8M,14M and 16M, ratio of NaOH to sodium silicate (Na 2SiO 3) 1, 1.5, 2 and 2.5, alkaline liquid to fly ash ratio 0.35 and 0.40 and replacement of water in Na 2SiO 3 solution by 10%, 20% and 30% were used in the pres ent study. The test results indicated that the high est compressive strength 54 MPa was observed for 16M of NaOH, ratio of NaOH to Na 2SiO 3 2.5 and alkaline liquid to fly ash ratio of 0.35. Lowest compressive strength of 27 MPa was observed for 8M of NaOH, ratio of NaOH to Na 2SiO 3 is 1 and alkaline liquid to fly ash ratio of 0.40. Alkaline liquid to fly ash ratio of 0.35, water replacement of 10% and 30% for 8 and 16 molarity of NaOH and has resulted in compressive strength of 36 MPa and 20 MPa respectiv ely. Superplasticiser dosage of 2 % by weight of fl y ash has given higher strength in all cases.