Mechanical properties of low-carbon Engineered Cementitious Composites with limestone and calcined clay under uniaxial cyclic compression

It is crucial to investigate the cyclic compression performance of low-carbon engineered cementitious composites(ECC) with limestone and calcined clay(LCC) during earthquakes.In this paper, the effects of water-binder ratios and replacement rates of LCC were investigated on the mechanical properties of LCC-ECC under uniaxial cyclic compression.The failure mode was observed, and the law of the stress-strain curves was summarized.The influences of the waterbinder ratio and LCC substitution rate on the stress degradation, stiffness degradation, and hysteretic energy dissipation were analyzed for specimens subjected to uniaxial cyclic compressive loading.The results showed that reducing water-binder ratio can effectively decrease the stiffness degradation and hysteretic energy dissipation, but had little effect on the stress degradation.The replacement rate of LCC significantly affected the stress degradation, stiffness degradation, and hysteretic energy dissipation of the specimens.In particular, the ductility and energy dissipation of the specimens were notably improved at a 50%.substitutionrate.Finally, a damage constitutive model for LCC-ECC under uniaxial cyclic compression is proposed.The model accurately predicted the unloading path, reloading path, residual strain development, and damage evolution of LCC-ECC. INTRODUCTIONDue to the brittle nature, low tensile strength and poor toughness of concrete, it is prone to mechanical performance degradation in harsh environments, which seriously affects the durability and safety of concrete structures and shortens the service life of engineering structures.To address these issues, Li et al. [1-3] developed a novel fiber-reinforced engineered cementitious composite (ECC) based on micromechanics and fracture mechanics principles.When the fiber volume content is only 2%, ECC material exhibits multi-crack and strain hardening behavior