The impact of moderate thermal fluctuations on dolomite: From strength enhancement to microstructural sensitivity

Abstract

Understanding the long-term effects of moderate thermal cycling on dolomite is vital due to its widespread use and prevalence in civil engineering, geological, and geotechnical applications, where materials are often exposed to daily temperature fluctuations. This study investigates the behavior of dolomite subjected to up to 500 natural thermal cycles between 20 and 60 °C, providing a comprehensive assessment of the material's physical and mechanical changes. Through systematic evaluation, the research revealed that the mechanical properties of dolomite—such as tensile, compressive, and shear strengths—initially improved significantly, with respective increases of 24.28%, 31.95%, and 42.96% observed up to 350 cycles. However, a slight decline in performance followed after 500 cycles, with these strengths decreasing by 3.59%, 4.48%, and 4.98%, respectively. Parallel trends were recorded across other physical and mechanical parameters, including density, porosity, ultrasonic velocity, and elastic moduli. Notably, while chemical and phase compositions remained stable under thermal exposure up to 70 °C, microstructural shifts—particularly in void volume—exhibited pronounced sensitivity. A reduction of 72.3% in void space after 352 cycles was followed by an increase of 46.9% at 500 cycles, strongly correlating with the observed mechanical trends. These findings highlight the critical role of thermal cycling in enhancing dolomite’s mechanical properties within a specific cycle range, offering valuable insights for engineering applications in thermally dynamic environments. The results are particularly relevant for infrastructure design, geothermal systems, and subsurface storage, where moderate thermal fluctuations are common, ensuring optimized material selection and long-term stability.

Keywords: Thermal Cycling, Dolomite, Tensile Behavior, Compressive Behavior, Shear Behavior, Fractures