Uniaxial Tensile Performance of PP-ECC: Effect of Curing Temperatures and Fly Ash Contents

Abstract

To investigate the influence of curing conditions and raw materials on the performance of engineered cement-based composites (ECCs), polypropylene fiber engineered cement-based composites (PP-ECCs) were designed and manufactured. The mathematical relationships between the fly ash content, curing temperature and PP-ECC tensile properties were explored by a uniaxial tensile test and by scanning electron microscopy. The results show the following: 1) with the increase in fly ash content and curing temperature, the ultimate tensile strain, ultimate tensile stress and tensile toughness index of the PP-ECC show a trend of first increasing and then decreasing, while the modulus of elasticity increases. 2) The optimum temperature is 20°C for the hydration reaction of the cementitious material inside the PP-ECC matrix. 3) When the fly ash content is 40% and the curing temperature is 20°C, the tensile mechanical parameters, ductility and toughness index of the PP-ECC are the best. This set of variables is recommended as a reference for PP-ECC engineering applications. 4) A mathematical relationship among the tensile strength, tensile strain and elastic modulus of the PP-ECC and coupling variables (fly ash content and curing temperature) is established.