Analysis of Concrete Block by Partial Replacement of Cement with Fly Ash

The objective of this research is to enhance theproperties of concrete by using Fly Ash as a partial substitutionof concrete. Tests carried out on cement are Initial and Finalsetting time and on aggregates, specific gravity and sieveanalysis. The mean target strength with given compressivestrength at 28 day and quality control level is calculated.Concrete blend proportions for the first tryout mix is calculatedand casting of cube of 15mm size with curing for 28 days, andthen test for strength using UTM/CTM machines. C-S-H gel aswell as Calcium hydroxide as bi product when reacts with water.C-S-H gel has an ability to keep the ingredients together bymaking a proper bond whereas lime which is freely available canreact with atmospheric moisture and cause efflorescence. In suchcases if we use fly ash, it reacts with free lime and produces C-SH gel again and water as bi product. We have used Fly ash as apartial replacement of cement with variation of fly ash inpercentage. In this study fly ash add in increment of 5%, 10%,15%, 20%, 25%, 30% and 35% replacement of cement which hasshown satisfactory results in the strength of the concrete. Fly Ashimproved the workability of the concrete, decreases the bleeding,surface finish and increases the cohesiveness. Compressivestrength is comparatively increased. The initial strength ofconcrete with fly ash has lower strength but acquires higherstrength after 56 days; which shows that more the nos. of curingdays more will be the strength. Thus, it can be used in areas ofconstruction such as dams, pavements etc.