Thermal characteristics of high-strength polymer–cement composites with lightweight aggregates and polypropylene fiber

Recently, research has been conducted using fibers to reduce the explosive spalling of concrete. Assessments of the volume fraction of polypropylene fiber in high-strength and lightweight concrete has shown that an optimum volume fraction of fiber reduces explosive spalling by discharging pore pressure and heat stress inside the concrete through the dissolution of fibers during exposure to high temperatures. In this study, we manufactured a high-strength polymer–cement mortar that can be used in repairs of many concrete structures by selecting three kinds of lightweight aggregate that have excellent heat interception performance, combined with varying volume fractions of polypropylene fiber to reduce explosive spalling. We analyzed the thermal characteristics and physical and mechanical properties of the mortar at high temperature. The analysis of test results for compressive strength, flexural strength, thermal conductivity, and thermogravimetric showed that a mixture of expanded perlite with high thermal stability and 0.2% polypropylene fiber showed the best physical, mechanical, and thermal characteristics.