EFFECTS OF SULPHATES ON ELASTIC MODULUS OF CONCRETE SAMPLES MADE FROM BLENDS OF CEMENT WITH OIL SHALE ASH

Concrete is a material both weak and strong. Its durability decreases under negative impact of several chemicals. In particular, when some sulphates in sea and ground waters react with cement paste, concrete expands and cracks; therefore, concrete has a very short life span. In that case, either the effects of sulphates should be suppressed as much as possible, or the per-formance of concrete should be increased. To increase the performance of concrete, some studies are in progress by adding some mineral additives to cement paste in predetermined ratios. In this study, the changes in moduli of static elasticity of the concrete (mortar) samples, produced by using Portland cement which contains 0, 15 and 30 % oil shale ash by mass, and cured in Na2SO4 and MgSO4 solutions, were examined. Concrete containing 15 % ash in cement gave optimum results