Mechanical and Physical Performance of Portland Cement Composites with Partial Replacements of Metakaolin and Ulexite

Abstract

Fabricating green binding materials are gaining a great importance in the construction sector recently. This rising interest is based upon the need for more sustainable and environment-friendly alternatives to conventional cementitious materials by utilizing waste materials and mineral by-products in the binding matrices through partial or complete replacement with Portland cement. In this paper, an experimental investigation was conducted to examine the effect of using a boron waste, namely ulexite, along with metakaolin as partial replacements with Portland cement. By this means, flow table, setting time, compressive and flexural strengths, unit weight, water absorption, and porosity tests were carried out on twelve different specimens, including the amount of ulexite of 5% and 7%, metakaolin of 10% and 20%, and amount of superplasticizer additive of 1%. The main conclusions of this work showed that using ulexite and metakaolin up to certain percentages is beneficial in terms of mechanical and physical properties. A further increase in the addition can lead to a decrease in the performance of the matrix.