Ultra-lightweight high ductility cement composite incorporated with low PE fiber and rubber powder

This paper presents the development and performance assessment of a novel ultra-lightweight high ductility cement composite (ULHDCC) incorporated with fly ash cenospheres, rubber powders and low fiber content of 0.7%. To address the brittle nature of such cement composite, this paper utilized the surface treated polyethylene (PE) fibers to improve the ductility behavior, and used rubber powders replacing part of cenospheres to reduce the matrix fracture toughness to achieve the pseudo-strain-hardening (PSH) performance. A fracture micromechanics-based investigation was performed to explain the high tensile ductility behavior of the ULHDCC. The mechanical properties including compressive and tensile strength, elastic modulus and microstructure has been experimentally examined. The results showed that the ULHDCC had the compressive strength ranging from 35.2 MPa to 43.5 MPa. The tensile strain in direct tensile test achieved 3% even with low fiber content of 0.7% PE fibers by volume. A relatively large amount of FAC (fly ash cenospheres) and rubber powder increased the entrapped air voids in the ULHDCC and reduced its density and strength. The ductility of ULHDCC was improved with the incorporation of rubber powder. Compared to normal engineering cement composite (ECC), to achieve similar tensile strain capacity the fiber content has been reduced 50% which leads to reduce the cost significantly.