Development of sustainable engineered cementitious composites with enhanced compressive performance at elevated temperatures using high-volume GGBFS

This study presents the development of an environmentally sustainable hybrid polyethylene (PE)-steel fibre reinforced engineered cementitious composites (ECC) to achieve enhanced compressive performance at elevated temperature. Utilizing a unique blend of industry by-products—ground granulated blast furnace slag (GGBFS), dolomite powder, and fly ash, with supplementary cementitious materials exceeding 50% replacement level, the developed ECC achieves remarkable improvement in compressive strength, both at ambient and elevated temperature conditions. A total of 340-cylinder specimens were tested to analyse the compressive properties after exposure to 20–800 °C, and the effect of different binders, fibre ratio on the residual compressive behaviour was investigated. Additionally, effects of the critical fire test parameters such as pre-drying and cooling treatment were also studied. The research findings indicate that incorporating high-volume GGBFS blends significantly improved the compressive performance of the ECC irrespective of the type of test parameters. Notably, a specific blend comprising of GGBFS, fly ash (GGBFS:fly ash = 1:0.2) and dolomite (15% by binder weight) demonstrated 138 MPa strength at room temperature and at least 75% and 45% strength retention at 600 °C and 800 °C, respectively. This was significantly higher than the values reported in literatures (∼48% at 600 °C and ∼12% at 800 °C) for similar type of ECC. The study also highlights the impact of sudden cooling in water and confirms the occurrence of both thermal shock and rehydration through microstructural analysis. Environmental impact analysis was also conducted to demonstrate the low carbon emission of the developed ECC.