INFLUENCE OF COARSE AGGREGATES AND MORTAR MATRIX ON PROPERTIES OF LIGHTWEIGHT AGGREGATE CONCRETES

Lightweight Aggregate Concrete (LWAC) with many advantages such as low density, good insulating capacity, and high fire resistance has been widely used around the world. LWAC may be considered as a two-component composite material consisting of a coarse aggregate and mortar matrix. The characteristics of these two components affect the properties of LWAC especially homogeneity. Therefore, this paper presents research results of the influence of lightweight coarse aggregates and mortar matrix on properties of this type of concrete. In the study, the raw materials were keramzit, polystyrene foam, type I cement, class F fly ash, and R4 plasticizer. A Suttard viscometer was mainly used to evaluate the workability named the flow of mortar. The experimental results showed that slump and segregation of concrete mixtures were remarkably increased when the flow of mortar was >= 21 cm; and the compressive strength of concrete was only about 40% and 20% the mortar strength when keramzit and polystyrene foam was used as coarse aggregates in the concretes respectively.