A study on the performance of lightweight self-consolidated concrete

Abstract

This paper presents a study on the fresh and hardened characteristics of lightweight aggregate concrete incorporating self-compacting agent (LWSCC). Self-compacting agent (SCA) (a polycarboxylic-based superplasticiser in combination with a viscosity-modifying admixture) and locally produced lightweight aggregate (LWA) produced from expanded clay type were utilised. Various LWSCC mixes made with different mix proportions, namely dosage of self-compacting agent, water/cement ratio, LWA/sand ratio and normal-weight aggregate as a partial replacement of LWA, were prepared. The initial slump flow, rate of slump flow loss and air content were then performed to assess the fresh properties of LWSCC. Twenty-eight-day compressive strength, ultrasonic pulse velocity, porosity and density were determined for investigating the hardened properties of LWSCC. The results reveal that, by using locally produced materials, it is possible to manufacture a structural LWA concrete with low density and high self-consolidating characteristics (flowability, deformability and stability). Both fresh and hardened characteristics of LWSCC are mainly controlled by dosage of an SCA, where the flowability, self-compactability, strength, homogeneity and porosity of LWSCC can be enhanced with increasing SCA content up to certain dosage of SCA (≈0·80), at which all these characteristics would start to decline with increasing SCA content. However, LWSCC loses its fresh parameters rapidly with increasing the dosage of SCA and lightweight aggregate/sand ratio. The results also showed that the compressive strength, homogeneity and porosity of LWSCC could be significantly improved by reducing the ratio of w/c and LWA/sand ratio, and utilising normal-weight aggregate in LWSCC mixes.