THE STANDARD DEVIATION IN CUBE STRENGTH RESULTS OF SELF-COMPACTING CONCRETE OF M40 GRADE USING QUARRY DUST AS FINE AGGREGATE AND FLY ASH POWDER AS FILLER

The reduction in the sources of natural sand and the requirement for reduction in cost of construction has led to an urgent need to identify a substitute for river sand. Quarry dust, which is a by product from the granite crushing processes in quarrying activity, is available abundantly and economically. This paper presents the study on the effect of replacing sand by quarry dust by 100% on the strength properties of self compacting concrete for M40 grade and also to find standard deviation in cube strength results. About 35 % of quarry dust powder having size between 600 micron to 300 micron. The results indicated that the standard deviation and coefficient of variation of cube test results for Mix 1, 2, 3 and 4 showed a variation between 3 MPa and 7.5 MPa and between 5% and 13% respectively. Lower cement content showed less standard deviation in compressive strength as compared to higher cement content. An average strength of 55.4 MPa of 31 cubes of Mix 2 has shown a standard deviation of 7.41 MPa and coefficient of variation of 13.4%.