Influence of The Activated Qatari Attapulgite Clay Admixture on The Mechanical Properties and Hydration Kinetics of Ordinary Portland Cement

Abstract

Blended cements are types of cements containing additives other than those used m Portland cement, which have considerable technological interest, because such addition increases the chemical resistance to sulfate and chloride attack. The present investigation represents a laboratory study, which provides a unique opportunity to introduce an effective practical attempt to deal with the problem of concrete deterioration m Qatar and the Arabian Gulf region, and to provide a solution to the problem by studying the production of blended cements. The mechanical properties and the hydration characteristics of the produced blended cements are also taken into account. The author produced for the first time in Qatar, mixes of blended cement using an original Qatari artificial pozzolana. The pozzolana was made by firing attapulgite clay at 600°C. Portland cement/artificial poz-zolana pastes were made using an initial water/solid ratio of 0.40 and hydrated at room temperature for various time intervals. The hydration characteristics of the hardened pastes were studied and related to their compressive strength values, combined water and free lime contents. The results could be useful as a prediction of the performance characteristics of the mixes.