Basic properties of structural LWAC based on waste and recycled materials

Abstract

© 2016 American Society of Civil Engineers. This paper presents results of experimental research on the impact of different types of lightweight aggregates and supplementary cementitious material (fly ash and metakaolin), on basic physical and mechanical properties of structural lightweight aggregate concrete (LWAC). The used aggregates are: lightweight aggregate obtained by firing waste materials (mixture of stone sludge, paper sludge, and fly ash) and expanded recycled glass. The results showed that it is possible to obtain structural LWAC with both types of lightweight aggregates even with substitution of cement with fly ash up to 45% (by mass). LWAC with high amount of active mineral admixtures and low water-binder ratio achieved higher compressive strength and specific strength compared to LWAC made only with portland cement. Comparison of static (Ec) and dynamic (Ed) modulus of elasticity showed that, for everyday engineering practice, static modulus of elasticity of LWAC can be determined using proposed expression Ec=0.65·Ed with high reliability.