Question

we can replace cement content by up to 60% slag but we can only use maximum of 10% silica as a replacement. why?

Answer 1

Answer

The cement can be replaced by slag up-to 60% because up-to 60% the compressive strength of this slag cement is similar to the conventional cement compressive strength.

Silica has good pozzolana properties and due to its fineness it can fill the pores and increases the density of the concrete and thereby increasing the strength of the concrete.This happens up-to 10% replacement of the cement by silica.But beyond 10% due to the less amount of cement ,the strength of the concrete start decreasing which is due to the increase in the water cement ratio.