An investigation on the application of acrylic resin agent for fiber/matrix bond strengthening in green engineered cementitious composites (ECC)

Green cementitious materials are usually developed by the addition of high volumes of mineral fillers. However, the addition of minerals can result in the reduction of mechanical strength. ECCs obtain their superior mechanical behavior from a high volume fraction of fibers. In ECCs, the matrix’s strength and the bond between the fibers and the matrix is a critical parameter, and if it becomes weak, the whole composite becomes weak or fibers may pull out of the matrix. In this study on green ECCs, to increase mechanical strength and also fiber/matrix bonding, the acrylic resin is used in 4 contents (e.g., 0, 2, 4, and 6 % in weight). The tests performed on ECC and plain cement paste (PCP) included tensile, compressive, and flexural. The results show that the acrylic increases the tensile strength, from about 2.0 MPa, up to 20 %, and compressive strength increased from about 88 MPa to 100 MPa. Due to the increase in ductility, the energy-based indexes increase more significantly. Acrylic resin optimum content was measured as 1.5–2.7 % (by weight). The trends show that acrylic resin is more effective for ECCs, because, in addition to enhancing the matrix strength, the resin increases the bonding strength between the matrix and fiber. Seeking the relationship between the results, nonlinear regression was used, and governing equations were presented. Also, using a regression model, the mechanical parameters were predicted successfully using input parameters.