Cement paste content as the factor influencing on compressive and splitting tensile strength of concrete

The study of high quantity of concretes with drastically differentiated composition (three types of cement, four levels of w/c ratio and three levels of paste content) has shown the significant influence on the compressive and splitting tensile strength of cement paste volume in this composite, after ninety days of hardening. It was establish that the relation between strength and paste content or w/c ratio can be sufficiently precisely interpreted as linear function. On the average, irrespectively of the value of w/c ratio, the increase of paste content of each 20 dm(3)/m(3) causes at every time the decrease of strength by about 2.5 MPa. The paste content increase in the case of concretes with lower strength (higher w/c ratio) has much higher effect than on concrete with higher strength. The experimentally established effect of paste content on concrete strength is so significant that it should be taken into consideration at the stage of its composition designing.