# Effects of Thermal Cycles on Mechanical Properties of RPECC: Static and Dynamic Compressive Performance

## TL;DR

This study examines how thermal cycles and rubber content affect the mechanical properties of a composite material, finding that 20% rubber content is optimal for performance under dynamic loading and temperature changes.

## Contribution

The study introduces a novel analysis of RPECC's mechanical behavior under thermal cycling and varying rubber content, revealing optimal rubber proportions for dynamic performance.

## Key findings

- Increasing rubber content from 10% to 30% improves toughness but reduces static compressive strength by up to 17.9%.
- Thermal cycling decreases static and dynamic compressive strengths by 18.0% and 41.2%, respectively, after 270 cycles.
- RPECC with 20% rubber content shows optimal strain rate sensitivity, with dynamic strength increasing by 6.9% to 9.9% at higher strain rates.

## Abstract

This study explores the impact of thermal cycling and rubber particle content on the static and dynamic compressive properties of rubber–polyethylene fiber-reinforced engineered cementitious composites (RPECC). Through static and dynamic compression tests, supplemented by scanning electron microscopy and energy-dispersive X-ray spectroscopy, the mechanical behavior and microstructural evolution of RPECC under thermal cycling were analyzed. Results indicate that increasing rubber content from 10% to 30% enhances toughness and strain capacity but reduces the static compressive strength of ECC by up to 17.9% at 30%. Thermal cycling reduced strength: static and dynamic compressive strengths decreased by 18.0% and 41.2%, respectively, after 270 cycles. Dynamic tests demonstrated that RPECC is sensitive to strain rate. For example, C-20 specimens exhibited increases in dynamic strength of 6.9% and 9.9% as strain rate rose from 60.2 s−1 to 77.4 s−1 and 110.8 s−1, respectively, and the dynamic increase factor correlated linearly with strain rate. By contrast, excessive rubber content (30%) diminishes dynamic strengthening, indicating that 20% rubber is optimal for enhancing strain rate sensitivity. Thermal cycling facilitates the formation of hydration products, such as calcium hydroxide, and creates interfacial defects, further deteriorating mechanical performance. These findings provide a reliable foundation for optimizing RPECC mix design and ductility in environments subject to temperature fluctuations and dynamic loading.