STUDIES ON BLENDED CEMENTS, IV

Abstract

1. Influence of mixing water content on concrete strength.
Influence of mixing water content on the early concrete strength of blended cements is little more than that of portland cement, but the strength at 28 days is almost the same.
2. Water cement ratio and workability of concrete.
The workability of concrete normally used at the field is given as following. For road 2-4cm, for building 19-23cm slump. When we use the blended or portland cement, these workability are given by the same water cement ratio.
3. The age at which the highest strength reached.
For the blended cement 6 or 9 months strength of 1:3 mortar and 1 year strength of concrete are highest. For portland cement 3 months strength of mortar and 6 months strength of concrete are also highest. The index of increasing strength of blended cements is greater than that of portland cements The following figure shows the index of increasing strength of mortars and concretes. (We adoptep the 28 days strength as standard.)