High temperatures affect the physical properties of red sandstone seriously, especially the pores. Understanding its mechanism is of great significance in coal mining following underground gasification, geothermal energy utilization, and the deep burial of nuclear waste. Nuclear magnetic resonance (NMR) was used to detect pore structure characteristics, and scanning electron microscopy (SEM) and polarizing light microscopy (PLM) were used to mechanism of change. The transverse relaxation time (T₂) and signal strengths of red sandstone treated at various temperatures were observed by NMR, and then, the pore situation can be obtained, and finally, the influence of temperature on the pore structure of red sandstone can be obtained. Microscopic photographs of the pores of red sandstone were obtained by SEM and PLM to assist in explaining the process of microstructural change, especially the influences of temperature on pore characteristics and grain morphology and distribution. The researches indicate that after the heat treatment of red sandstone at 25–1300 °C, the pore and strength characteristics change in well-defined stages. Before 500 °C, the pore diameters and distribution range increase, but the porosity and internal grain structure do not change significantly. At 500–1000 °C, red sandstone micropores contract, mesopores and macropores develop, and strength decreases. After 1000 °C, the grains that comprise sandstone melt and fill many of the pores, decreasing porosity. The proportion of micropores decreases, while mesopores and macropores increase. In addition, a large number of bubbly holes appear in and on the sandstone, presumably caused by gases such as CO₂, and water vapor from dehydrating grains. The changes in pore and cementation states with temperature are the main factors affecting the tensile strength of red sandstone.

高温会严重影响红砂岩的物理性质，尤其是孔隙。了解其机理在地下气化，地热能利用和核废料的深埋之后的煤矿开采中具有重要意义。核磁共振（NMR）用于检测孔结构特征，扫描电子显微镜（SEM）和偏振光显微镜（PLM）用于改变机理。横向弛豫时间（T ₂），并通过NMR观察了在不同温度下处理后的红砂岩的信号强度，然后可以得出孔隙状况，最后可以获得温度对红砂岩孔隙结构的影响。通过SEM和PLM获得了红砂岩孔隙的显微照片，以帮助解释微观结构的变化过程，特别是温度对孔隙特征，晶粒形态和分布的影响。研究表明，在25–1300°C的温度下对红砂岩进行热处理后，孔隙和强度特性会在明确的阶段发生变化。在500°C之前，孔径和分布范围增大，但孔隙率和内部晶粒结构没有明显变化。在500–1000°C，红砂岩微孔收缩，中孔和大孔发展，强度降低。1000°C之后，包含砂岩的颗粒融化并填充了许多孔隙，从而降低了孔隙度。微孔的比例减少，而中孔和大孔增加。此外，砂岩中和砂岩上会出现大量气泡，可能是由诸如二氧化碳等气体引起的₂，和谷物脱水产生的水蒸气。孔隙和胶结状态随温度的变化是影响红砂岩抗拉强度的主要因素。