高温后地质聚合物混凝土损伤特性试验

采用矿渣和粉煤灰为原料,硅酸钠和氢氧化钠为激发剂,制备了矿渣粉煤灰基地质聚合物混凝土,通过超声波检测及抗压强度试验,研究了不同温度、不同冷却方式下SFGC的质量损失及力学、声学特性变化规律。结果表明,高温总体上导致SFGC的质量、抗压强度及纵波波速减小,峰值应变增大,频谱中高频成分衰减; 冷却方式对高温后SFGC的损伤演化具有显著影响,经浇水冷却后的试件较自然冷却情况性能退化更为严重; 600 ℃为SFGC性能突变的临界温度,600 ℃之后,其性能急剧劣化。

Experimental research on damaged characteristics of geopolymeric concrete after elevated temperature

The slag-fly ash-based geopolymer concrete(SFGC)was made of sodium silicate and sodium hydroxide alkali-activated slag and fly ash. The weight loss, mechanical properties and acoustic properties of SFGC under various elevated temperatures by different cooling methods were studied through ultrasonic testing and compressive strength testing. The results indicate that generally the elevated temperature results in the decrease of weight, compressive strength and longitudinal wave velocity, the increase of the peak strain and the attenuation of the high frequency composition of the frequency spectrum. The influence caused by the cooling methods on the damage evolution of SFGC after elevated temperature is obvious, and the specimens cooled by spraying water have a greater deterioration compared with those cooled naturally. The critical temperature of SFGC is 600 ℃. The properties of SFGC deteriorate sharply after 600 ℃.