Calcium aluminate cement based high early strength engineered cementitious composites with recycled artificial flaws

Engineered Cementitious Composites (ECC) is an ideal repair material due to its high durability and ductility. However, providing ECC with high early strength is challenging since strength and ductility, which are key to crack-free repair, are also interdependent. Thus, it is necessary to use artificial flaws in order to keep the ductility at reasonable levels while increasing the strength. This study uses calcium aluminate cement, a non-portland cement, as the primary binder to attain the early strength in the production of high early strength ECC for the first time. Besides, expanded glass and crumb rubber, both made by recycling waste materials, were included as artificial flaws to enhance ductility. The performance of designed high early strength ECC was assessed through mechanical, abrasion, shrinkage and non-destructive tests and compared with high early strength portland cement based ECC. It is revealed that a minimum compressive strength of 28.9 MPa and flexural strength of 7.1 MPa could be attained even at the age of as early as 6 hours after casting. Nevertheless, deformation capacities were significantly improved after 24 hours following the casting by the use of both artificial flaws. In addition, acceptable drying shrinkage and abrasion resistance values were obtained.