Engineered cementitious composites using blended limestone calcined clay and fly ash: Mechanical properties and drying shrinkage modeling

Concern about carbon reduction in the construction industry is growing. Engineered cementitious composites (ECC) have been extensively studied for their potential sustainability, continuous efforts are being made for a greener ECC. In this study, a new type of low-carbon supplementary cementitious materials (SCMs), limestone calcined clay (LC2), was blended with fly ash (FA) as the cementitious materials of ECC. A series of experiments were carried out to study the effects of blended LC2/FA on the mechanical properties and drying shrinkage of ECC materials, XRD and MIP were also used to explain the mechanism. The results show that LC2 can accelerate the hydration, improve the mechanical properties of ECC, especially in the early age. The addition of LC2 can improve the flexural bearing capacity, but weaken the bending deformation capacity and affect the flexural toughness. The increase of LC2 content significantly refined the pore size, thus reduced the drying shrinkage. In addition, based on the drying shrinkage model of ordinary concrete, the improved drying shrinkage model proposed in this study can accurately describe the drying shrinkage behavior of ECC.