Investigation of Drying Shrinkage Characteristics in Lightweight Engineered Cementitious Composites

Abstract

Lightweight engineered cementitious composites (LW-ECCs) not only offer comparable mechanical strengths compared with conventional concrete, but also increase the tensile strain of the composite and exhibit strain-hardening behavior, and can be utilized in weight-critical structures such as buildings in seismically active areas. Hollow glass microsphere is a type of ultra-lightweight inorganic non-metallic hollow sphere and it has been deemed as one of the potential sustainable fillers of cement composites. This study aims to investigate the drying shrinkage behavior of LW-ECCs mix designs incorporating different types of hollow glass microspheres (HGMs). Eight types of HGMs with different densities (0.2–0.6 g/cm3) and particle size distributions were incorporated to replace fly ash at 80 and 100 vol% with HGMs. Drying shrinkage was measured from the age of 2 days and up to 91 days. The results demonstrate that all LW-ECCs at 91 days showed greater shrinkage than the control mix, deformation ranged from 1140–1877 µε; 80% replacement ratio of HGMs was regarded as the optimum due to less shrinkage than 100% HGM mixes; the mix incorporating 80% H60 type of HGMs was the relatively most desired mix which had the least shrinkage at 91 days compared to other LW-ECCs, and the strains of the mix using H60 were 1140 and 1385 µε at 91 days for 80% and 100% replacement, respectively.

Keywords

• lightweight engineered cementitious composites
• hollow glass microspheres
• drying shrinkage
• shrinkage strain