image: The schematic illustrates how increasing temperature alters the tensile behavior of rubber-modified engineered cementitious composites (R-ECC). At sub-high temperatures (70–100 °C), moderate matrix degradation, rubber softening, and fiber softening promote fiber pull-out and multiple cracking, leading to enhanced ductility. At higher temperatures (150 °C), severe interfacial degradation, increased porosity, and fiber melting significantly reduce crack control capacity and tensile performance.
Credit: Lifeline Emergency and Safety, Tsinghua University Press
Engineered Cementitious Composites (ECC) are well known for their high tensile ductility and superior crack control capacity, making them attractive for resilient and damage-tolerant infrastructure. However, most existing studies on ECC under elevated temperatures focus on residual mechanical properties after thermal exposure, providing limited understanding of its real-time mechanical response and microstructural evolution under in-service thermal conditions.
In a recent study, the research team from Guangdong University of Technology and University of South Australia investigated the tensile behavior of rubber-modified ECC (R-ECC) subjected to coupled thermal–mechanical loading, aiming to bridge this knowledge gap. Rubber particles were introduced as partial replacements for quartz powder at ratios of 0%, 10%, 20%, and 30%, and quasi-static uniaxial tensile tests were conducted at temperatures of 25 ℃, 70 ℃, 100 ℃, and 150 ℃. The study systematically examined mass loss, pore structure, cracking behavior, and tensile stress–strain responses under real-time elevated temperature conditions.
The team published their work in Lifeline Emergency and Safety on December 10, 2025.
“Increasing temperature generally leads to reductions in initial cracking strength and ultimate tensile strength of R-ECC. Nevertheless, within the sub-high temperature range of 70–100 ℃, R-ECC exhibited notably enhanced tensile ductility, with the highest ultimate tensile strain observed at 100 ℃,” said Jia-Xiang Lin, corresponding author of the paper, associate professor in the School of Civil and Transportation Engineering at Guangdong University of Technology.
According to the authors, this ductility enhancement is attributed to a combination of moderate matrix degradation, fiber softening, and improved fiber pull-out behavior. Microstructural analyses revealed that controlled water loss, increased porosity, and gradual deterioration of the interfacial transition zone weakened the matrix sufficiently to promote multiple cracking without causing abrupt failure. At the same time, polyethylene fibers retained effective bridging capacity, enabling stable strain hardening behavior.
In contrast, at 150 ℃, the tensile performance of R-ECC deteriorated sharply. Severe microstructural damage, fiber melting, and interfacial degradation led to a pronounced loss of strength and ductility, highlighting the upper temperature limit for effective ECC performance under coupled loading conditions.
The study also compared real-time thermo-mechanical loading with conventional high-temperature exposure tests. “Tensile strength degradation occurred earlier and was more pronounced under coupled loading. For example, approximately 40% strength loss was recorded at 70 ℃, even though previous studies reported partial strength recovery after cooling. This discrepancy underscores the importance of considering in-service temperature effects rather than relying solely on post-exposure evaluations,” said Jia-Xiang Lin.
The findings provide important guidance for the practical design and application of rubber-modified ECC in structures exposed to sustained sub-high temperature environments, such as industrial facilities, underground infrastructure, and energy-related engineering systems. The study highlights the potential of rubber-modified ECC to maintain effective crack control and tensile deformability under realistic service conditions, while also defining critical temperature thresholds beyond which performance degradation becomes significant.
Article Title
Tensile behavior and microstructural evolution of rubber-modified ECC under thermo-mechanical loadings
Article Publication Date
10-Dec-2025