Effects of Thermal Cycles on Mechanical Properties of RPECC: Static and Dynamic Splitting Tensile Performance.

This paper examines the splitting tensile properties of rubberized polyethylene-engineered cementitious composites (RPECC) through static and dynamic experimental tests, highlighting the effects of thermal cycles, impact strain rates, and rubber powder substitution rates for fine aggregates. Damage patterns, ultimate tensile strength, time-dependent stress curves, dynamic failure strain, and the dynamic increase factor of the RPECC are presented. The microstructure of the material is analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Experimental results reveal that incorporating rubber powders significantly enhances the deformability and ductility of RPECC in splitting tension. However, a high content of rubber powders, such as a substitution percentage of 30%, significantly reduces static and the dynamic ultimate tensile strength of the RPECC by 16.8% and 34.2%, respectively. Microstructural examinations indicate that thermal cycling weakens the internal adhesion between the rubber particles, polyethylene fibers, and the ECC matrix, resulting in the frequent withdrawal of fibers and the formation of calcium hydroxide, which diminishes the material tensile strength by up to 20.6% in static tests and 45.1% in dynamic tests. Despite these challenges, the RPECC with 20% rubber achieves a favorable balance between splitting the tensile properties and thermal resistance, even after undergoing 270 heat-cool cycles, suggesting its potential applicability in harsh environments.