Development of high-early-strength low-carbon engineered cementitious composites with calcium sulfoaluminate cement incorporating high-volume fly ash

Engineered cementitious composites (ECC) is an ultra-durable construction material owing to its high tensile ductility and intrinsic crack width control. Here, a high-early-strength ECC (HE-ECC) was developed using calcium sulfoaluminate (CSA) cement with high-volume fly ash to facilitate rapid and sustainable repair application. Two water-to-binder ratios (0.25 and 0.35) and four fly ash dosages (50-80 wt% by binder mass) were investigated, and PVA fiber was added at 1.5 vol%. The composite mechanical properties were analyzed in association with the early hydration process. At 1 day, the HE-ECC was found to attain a tensile strain capacity of 3-4% while maintaining an ultimate tensile strength of 2-5 MPa. Most groups can maintain a tensile strain capacity over 3% at 28 days with an ultimate tensile strength of 3.1-5.4 MPa. The environmental impacts for producing HE-ECC can be reduced significantly, accounting for-38.7% less energy and-44.6% less carbon emission compared to conventional ECC. The satisfying early age me-chanical performance makes it applicable for many constructions and the high sustainability of HE-ECC makes it promising to reduce environmental impacts substantially.