Evaluating next-gen sustainable cementitious materials: Unleashing the potential of LC3-based composites under high-temperature environments

Abstract

Limestone calcined clay cement (LC³⁾, a low-carbon building material that substitutes for ordinary Portland cement (OPC), offers notable environmental and economic benefits, reducing carbon emissions by approximately 40 % and production costs by 25 %. As a promising low-carbon building material, the dense microstructure of LC³-based composites has a dual effect: it enhances mechanical strength but diminishes resistance to high temperatures. To extend the application scenarios of LC³-based composites, this paper provides the first in-depth analysis of their mechanical performance at both room and elevated temperatures, along with the effects of fiber reinforcement. Our findings reveal that the LC³ substitution rate can reach 50 %–60 %, improving compressive strength, flexural strength, and ductility but negatively impacting tensile strength and high-temperature resistance. Temperatures of 400 °C and 800 °C are key thresholds, with severe strength loss occurring above 800 °C. Compared to OPC-based composites, LC³'s complex composition and hydration products result in more severe microstructural damage at high temperatures. The inclusion of fibers, such as PP fibers, steel fibers, and modified polymer fibers, can reduce strength loss and prevent spalling at high temperatures. However, research on the high-temperature performance of fiber reinforced LC³ (FRLC³) remains limited, and the failure mechanisms are not yet fully understood. This paper summarizes and compares existing research, proposing that future studies focus on key issues such as improving the LC³ substitution rate in FRLC³, expanding fiber types, optimizing component design, and clarifying the fiber mechanisms, which are crucial for the development of high-temperature-resistant FRLC³ composite materials.