Mechanical properties of alkali-activated slag lightweight aggregate concrete

Abstract

The mechanical properties of alkali-activated slag lightweight aggregate concrete (AAS-LWAC) were deep investigated. A total of 108 AAS-LWAC samples were prepared for compressive strength test, splitting tensile strength test, and flexural strength test. The microstructures of AAS-LWAC were characterised in depth using scanning electron microscopy (SEM). Compared with clay ceramsite and shale ceramsite as the lightweight aggregate (LWA), AAS-LWAC with fly ash ceramsite as the LWA exhibited the highest compressive strength. Besides, the compressive, splitting, and flexural strengths of AAS-LWAC decreased with increasing LWA content. Moreover, compared with polypropylene fibres and basalt fibres, steel fibres can significantly increase the compressive, splitting, and flexural strengths of AAS-LWAC, with an optimal volume content of 0.6% steel fibre. Furthermore, a modified formula for the variation in compressive strength of AAS-LWAC over time was proposed, considering the influence of LWA.