Effects of Multiple Supplementary Cementitious Materials on Workability and Strength of Lightweight Aggregate Concrete

Abstract

The use of supplementary cementitious materials (SCMs) in concrete has increased worldwide because of their economic and environmental benefits. Supplementary cementitious materials include silica fume (SF), blast furnace slag (BFS), fly ash (FA) and rice husk ash (RHA), which are generally derived from industrial byproducts and agro-wastes and can be mixed with blended cement to enhance concrete strength. The use of SCMs in concrete in conjunction with lightweight aggregate not only reduces the consumption of Portland cement, but also decreases the weight of structure, thus lessening the cost of construction. In the present experimental study, the effects of different SCMs (SF, BFS and FA) on mechanical strength properties and workability of lightweight aggregate concrete (LWAC) are tested with partial replacement of cement by SCMs in various proportions and combinations. From the test results and considering rheological and strength properties of concrete and economic benefits, the best combinations of SCMs obtained are the BFS-FA combination and the FA-SF-BFS combination.