This paper reports an experimental study of the influence of elevated temperature on alkali activated slag (AAS) and slag-metakaolin (MK) systems. The residual compressive and flexural tensile strengths, ultrasonic pulse velocity (UPV) and porosity and water absorption ratios of AAS and AAS-MK composites after subjected to elevated temperatures of 200, 400, 600, 800, and 1000°C were investigated. Two different procedures were applied for cooling the specimens. The changes in the microstructure of the composites after subjected to high temperature were examined with scanning electron microscope and X-ray diffraction. Test results reveal that depending on the increasing temperature, the residual compressive strength, flexural tensile strength, and UPV values of the specimens decreased, and porosity and water absorption ratios increased. The minimum strength results of AAS and AAS-MK specimens were observed at 800 and 600°C, respectively. In particular, there have been significant changes in the internal structure of AAS and AAS-MK specimens exposed to 1000°C and new reaction products were observed. Test results have shown that AAS specimens are a new alternative that can be developed for use in environments exposed to high temperatures. Since this new composite contains only slag binder and slag aggregate, it can be an economical product that use fully recycled material and these properties can increase the application areas of environmentally friendly material.

中文翻译：

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高温下碱活化渣和渣-偏高岭土混合物的力学性能和微观结构的研究

本文报道了高温对碱活化渣 (AAS) 和渣-偏高岭土 (MK) 系统影响的实验研究。研究了 AAS 和 AAS-MK 复合材料在 200、400、600、800 和 1000°C 高温后的残余压缩和弯曲拉伸强度、超声脉冲速度 (UPV) 以及孔隙率和吸水率。采用两种不同的程序来冷却样品。用扫描电镜和X射线衍射仪观察了复合材料高温后微观结构的变化。试验结果表明，随着温度的升高，试样的残余抗压强度、抗弯抗拉强度和UPV值降低，孔隙率和吸水率增加。AAS 和 AAS-MK 试样的最小强度结果分别在 800 和 600°C 下观察到。特别是暴露于 1000°C 的 AAS 和 AAS-MK 样品的内部结构发生了显着变化，并观察到了新的反应产物。测试结果表明，AAS 试样是一种新的替代品，可以开发用于暴露于高温的环境中。由于这种新型复合材料仅包含矿渣粘合剂和矿渣骨料，因此可以成为使用完全回收材料的经济产品，这些特性可以增加环保材料的应用领域。暴露于 1000°C 的 AAS 和 AAS-MK 样品的内部结构发生了显着变化，并观察到了新的反应产物。测试结果表明，AAS 试样是一种新的替代品，可以开发用于暴露于高温的环境中。由于这种新型复合材料仅包含矿渣粘合剂和矿渣骨料，因此可以成为使用完全回收材料的经济产品，这些特性可以增加环保材料的应用领域。暴露于 1000°C 的 AAS 和 AAS-MK 样品的内部结构发生了显着变化，并观察到了新的反应产物。测试结果表明，AAS 试样是一种新的替代品，可以开发用于暴露于高温的环境中。由于这种新型复合材料仅包含矿渣粘合剂和矿渣骨料，因此可以成为使用完全回收材料的经济产品，这些特性可以增加环保材料的应用领域。