The investigating on mechanical properties of engineered cementitious composites with high ductility and low cost

Abstract

The engineering application of engineered cementitious composites(ECC) has always been limited by its cost, which mainly due to the high price of imported PVA fibers. In order to balance the mechanical properties and cost of ECC, this study presents an engineered cementitious composites with high ductility and low cost. The compressive strength, uniaxial tensile strain and uniaxial tensile strength of this ECC were 21.33 MPa, 5.10%, and 2.93 MPa, respectively. The high ductility and low cost of this ECC are mainly attribute to the reasonable combination of four materials, including PVA fibers, fly ash, CaCO3 whiskers(CW) and nano-CaCO3(NC). The optimal mixing ratio of the four materials is that the content of PVA fiber is 1.3%(vol%), the mass ratio of fly ash to cement is 3.0, 1% CW(vol%), and 1% NC(wt.%). The average crack width and the maximum crack width on the surface of the tensile specimen prepared according to the optimal mixing ratio can be controlled at about 42 μm and 100 μm, respectively. This excellent crack control ability mainly comes from the crack inhibition effect of PVA fibers and CW. Compared to classic ECC-M45, the total value coefficient and total cost of the specimens prepared according to the optimal mixing ratio were 112.59% and 36% of that of ECC-M45, respectively. And the designed ECC with high ductility and low cost has the applicability of engineering application, which has been proved by comparison with the mechanical properties of a sprayable ultra high toughness cementitious composites (UHTCC) that has been applied in practical engineering cases.