High-modulus and low-shrinkage hybrid-fiber reinforced engineered cementitious composites (ECC)

Engineered cementitious composites (ECC) characterizes with high strain capacity, accompanied by two notable disadvantages, i.e., low elastic modulus and severe shrinkage yet. A new type of ECC featuring relatively high tensile strain capacity, high elastic modulus as well as low shrinkage was developed by using polyethylene fiber (PE) alone (P-ECC), or hybrid combining PE fiber with steel fiber (H-ECC) in this research. The effects of sand-to-binder ratio (s/b) from 0.42 to 1.02 and fiber hybridization on compressive properties, tensile properties and shrinkage characteristics of ECC were systematically investigated. Experimental results indicated that the increase of s/b ratio could benefit the compressive strength, the elastic modulus and the shrinkage performance of ECC. The elastic modulus as well as the shrinkage properties of P/H-ECC were superior than those of traditional ECC. It is noted that H-ECC with extremely high s/b ratios (i.e., 0.72-1.02) exhibiting relatively high tensile strain capacity, comparable elastic modulus with normal strength concrete and obviously lower total shrinkage than traditional ECC, is an ideal and competitive material which can be utilized in critical structural elements characterized by deformation compatibility and desirable ductility.