Evaluation of Mechanical and Thermal Properties of Heat-Treated Natural Analcime-Bearing Rock: Based on Mineralogical Structure

The present study aimed to investigate the mineralogical–petrographic, physical, chemical, mechanical, and thermal properties of natural analcime-bearing rocks, evaluating their feasibility for prospective engineering and material applications. Natural analcime-bearing rocks are widely utilized in various sectors due to their ease of processing and distinctive thermal performance characteristics. To determine the physical–mechanical and thermal pathways of the material under thermal stress, specimens were exposed to high temperatures in a laboratory furnace using a gradient threshold (Untreated, 300 °C, 400 °C, 500 °C, 600 °C, 700 °C, 800 °C, 900 °C, and 1000 °C) and variable holding durations (1, 2, and 3 h). The specific heat capacity (Cp) values of both the untreated and post-treated specimens, evaluated strictly at a standardized isothermal DSC measurement temperature of 25 °C, exhibited a progressive enhancement following dynamic thermal soaking. While the baseline Cp value of the untreated natural rock was 0.616 J⋅g−1⋅K−1, the specific heat capacities of the samples pre-heated at 300 °C, 400 °C, 500 °C, 600 °C, 700 °C, 800 °C, 900 °C, and 1000 °C were determined as 0.754, 0.679, 0.605, 0.541, 0.693, 0.499, 0.660, and 0.472 J⋅g−1⋅K−1, respectively. Regarding heat transfer, the baseline thermal conductivity of the untreated rock was 1.000 W⋅m−1⋅K−1. A precise reduction of 40.5% was observed after a 3 h heating process at 300 °C (dropping to 0.595 W⋅m−1⋅K−1), while exposure to 1000 °C for 3 h caused the thermal conductivity to contract by 44.9% (to 0.551 W⋅m−1⋅K−1) due to lattice alterations. The results indicate that the highest compressive and flexural strengths were generally observed around 600 °C, strongly depending on the treatment duration. Beyond the peak thresholds, the samples exhibited a progressive decline; however, the retention of a substantial portion of the baseline strength even at 1000 °C suggests a notable thermal durability for the natural analcime-bearing rock. In conclusion, the empirical findings indicate that natural analcime-bearing rock possesses promising characteristics that support its potential candidate suitability for prospective utilization in thermal insulation elements and eco-efficient construction matrices, provided that long-term life-cycle durability cycles are validated in future research lines.