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通过对高温作用后混凝土力学性能试验及扫描电镜观察,研究了温度对高温后混凝土力学性能及微观特性的影响。研究结果表明:随着温度升高,混凝土抗压强度持续降低,强度-位移曲线的峰值点呈向右向下移动趋势。就微观特性而言,原始素混凝土水泥浆体密实、无明显孔洞,水泥浆体与骨料之间黏合紧密,观察不到裂缝;400℃水泥浆体与骨料之间出现裂缝,600℃水泥浆体与骨料之间裂缝宽度显著增大,浆体中出现整体网状裂缝且局部出现较大的粉状颗粒;800℃水泥浆体与骨料之间完全脱落,浆体疏松明显。
The effect of temperature on the mechanical properties and microscopic properties of concrete after high temperature was studied through the mechanical properties test and scanning electron microscope observation of the concrete after high temperature. The results show that as the temperature increases, the compressive strength of concrete decreases continuously, and the peak point of the intensity-displacement curve moves downward to the right. In terms of the microscopic characteristics, the cement of the prime concrete is compact and has no obvious holes. The cement paste and the aggregate are closely adhered to each other and no cracks are observed. Cracks occur between the cement paste and the aggregate at 400 ℃, The width of cracks between the slurry and the aggregates increased significantly. The whole meshed fractures appeared in the slurry and large powder particles appeared locally. The cement slurry and aggregates at 800 ℃ completely fell off and the slurry became loose obviously.