Relative evaluation of performance of limestone calcined clay cement compared with Portland pozzolana cement

Abstract

Cement is most widely used binder to produce concrete and the most common construction mate-rial today. Though concrete is a material with the lowest greenhouse emission, cement has the highest. With the carbon footprint of cement accounting for over 7% of total world emissions, it becomes single most im-portant material of environmental concern around the world. This concern has led to a search for lower car-bon emitting binders and use of blended cements, incorporating large number of natural and industrial by-products. This paper describes the performance of a composite cement binder consisting of calcined clay, limestone, and Portland cement clinker as compared to a traditionally used fly ash based Portland pozzolana cement. This study reports behavior of the two cement binders with respect to strength development, hydra-tion, porosity of hydrated pastes, normal consistency, and admixture response with ageing. This study finds that, though the clay based cement attains higher early age strength, the later age strength in mortar is lower as compared to commercial fly ash based cement. Further the clay based cement has higher water demand, but lower porosity compared to composite cement binder.