Feasibility of Using the Hollow Glass Microsphere to Develop Lightweight CAC-GGBFS-Blended Strain-Hardening Cementitious Composites

Strain hardening cementitious composites (SHCCs) with superior tensile strength and ductility have been utilized as an effective repair material. A corrosion-resistant binder, calcium aluminate cement (CAC)–ground granulated blast-furnace slag (GGBFS) blends, has been introduced into SHCC to expand its application in the concrete sewage network rehabilitation. As a repair material, the lightweight property is particularly favorable as it can broaden its functionality. This article presents a study on developing a novel lightweight CAC-GGBFS-blended SHCC using hollow glass microsphere (HGM), namely, HGMLW-SHCCs. The fine silica sand content was substituted with HGM at 25, 50, 75, and 100 vol% in HGMLW-SHCC. We examined flowability, density, uniaxial compressive behavior, direct tensile behavior, and pseudo strain-hardening indices. Microstructure analysis was also conducted to understand the meso-scale behavior of this new lightweight composite. The newly developed HGMLW-SHCC had a 28-day density of only 1756 kg/m 3 . Compressive and tensile strengths were determined in the range of 62.80–49.39 MPa and 5.81–4.19 MPa, respectively. All mixtures exhibited significant strain-hardening behavior. Even though the increased HGM content negatively affected the tensile strength of HGMLW-SHCC, it had a positive effect on its ductility. In addition, HGM can reduce crack width and tensile stress fluctuations significantly. The results showed that HGM was a promising material for producing strong and lightweight corrosion-resistant SHCCs to be used as a retrofitting material in the wastewater industry.