Mechanical and self-healing properties of calcium-sulfoaluminate-cement-based engineered cementitious composites (ECC)

Abstract

Calcium sulfoaluminate (CSA) cement is uniquely suited for repair work, however, the CSA cement-based material is more vulnerable to cracking, and thus may cause the useless repairing. In this paper, CSA cement-based engineered cementitious composites (CSA-ECC) was developed for ensuring the reliability and durability of repair applications, meanwhile, the crumb rubber (CR) was incorporated to improve its tensile properties, and thus avails the self-healing. The results showed that the compressive strength of the CSA-ECC can achieve 38.1 MPa at 3 days, and can further developed to 60.7 MPa at 28 days. The incorporation of CR resulted in the coarsening of microstructure, and thus decreased compressive strength of CSA-ECC to around 50 MPa. In term of tensile properties, all CSA-ECC mixtures exhibited high ductility with strain capacity of 3.13–5.34%. The CR addings effectively increased strain capacity while negatively affected tensile strength and drying shrinkage of CSA-ECCs. Moreover, the crack width was narrowed within 52 μm as compared with 92 μm that of reference mixture, due to which the self-healing was promoted in rubberized CSA-ECC, as a result, its recover percentage in tensile stiffness, strength, and strain of pre-cracked CSA-ECC was improved upon self-healing.