High-temperature response characteristics of loess porosity and strength

Soil protection is a critical issue in the UN Sustainable Development Goals (SDGs). In this light, understanding the changes in the micropore structure of loess—which have a great influence on its macroscopic physico-mechanical properties—is crucial. Temperature is one of the main factors affecting the porous structure of loess; to ascertain the effects of high temperatures on the porous distribution of loess, Malan loess was sampled from the Shaanxi Province of China. The changes in porous characteristics of the loess samples after being subjected to high temperatures were tested using a non-destructive method—nuclear magnetic resonance (NMR)—and the tensile failure load of the loess at different temperatures were obtained. The results show that NMR can be used to characterize the variations in loess pores with temperature. In general, the porosity of loess decreases with increases in temperature. For temperatures above 600 °C, the pore radius begins to increase with increases in temperature; further, pore connectivity is improved at high temperatures, between 200 °C and 800 °C. The tensile failure load of loess not only increases exponentially with increases in temperature, but also there is an exponential relationship between porosity and tensile failure load.