Absorbed Energy and Fracture Characteristics of Cement Paste Modified with SBR Latex Through Charpy and Three-Point Bending Tests

This study evaluates the energy absorption, fracture energy, tensile strength, and compressive strength of cement paste modified with SBR latex. A control mixture with a water-to-cement (W/C) ratio of 0.4 was used as the reference. Based on this, modified mixtures were prepared by partially replacing water with SBR latex at P/W ratios of 0, 5, 10, 15, and 20 wt% relative to the original water content. The samples were cured for 7, 14, and 28 days. To assess the mechanical properties and energy absorption capacity, a series of tests were conducted, including compressive strength, tensile strength, Charpy impact testing, and three-point bending tests to measure fracture energy. The results show that the optimal P/W ratio is 10%, at which tensile strength increased by 42.1%, energy absorption increased by 36.3%, and fracture energy increased by 29.6%, while compressive strength decreased by a maximum of 11.6%. A linear relationship between fracture energy and energy absorption after 28 days was proposed, allowing for the estimation of fracture energy from energy absorption data. This research not only identifies the optimal latex dosage for the design of SBR-modified cement paste but also provides foundational data for applying Charpy impact testing and three-point bending testing to cement-based materials.