Hygro-thermo-mechanical characterization of stabilized rammed earth materials exposed to elevated temperatures
摘要
The resurgence of sustainable construction practices has led to a renewed interest in earth-based building methods. Among these, rammed earth (RE)—particularly stabilized one—is preferred due to its sustainability, high thermal buffering capacity, and relatively low cost. This study investigates the influence of cementitious stabilizers on their structural, thermal and moisture-related behavior under elevated temperatures. REs were constructed with cement ratios ranging from 0 to 20%. The hygro-thermo-mechanical characteristics of the specimens were measured before and after exposure to temperatures of 200, 400, 600, and 800 °C. The effectiveness of the random forest method was evaluated to predict the hygro-thermo-mechanical properties of RE. A multi-criteria optimization was implemented considering cost, greenhouse gas emissions, and hygro-thermo-mechanical properties. The findings demonstrated that exposure to elevated temperatures reduced the hygrothermal performance and mechanical properties of rammed earth materials. On average, RE specimens with 15% cement (C15) have lost 20% of their hygrothermal capacity and 60% of their mechanical capacity at the highest temperature. The addition of cement improved the overall behavior of the rammed earth specimens exposed to high temperatures. The R2 values for predicting six criteria—time lag, thermal conductivity, WVDRF, moisture buffering capacity, compressive strength, and modulus of elasticity—were above 0.83, confirming the model's reliability. Ultimately, the 15% cement mix is recommended as optimal, demonstrating balanced hygro-thermo-mechanical performance, reduced environmental impact, and cost efficiency.