This study aims to investigate the cracking potential of alkali-activated slag (AAS) and alkali-activated slag-fly ash (AASF) concrete subjected to restrained autogenous shrinkage. Temperature Stress Testing Machine (TSTM) is utilized, for the first time, to monitor the stress evolution and to measure the cracking time of alkali-activated concrete (AAC) under restraint condition. The stresses in AAS and AASF concrete are calculated based on the experimental results while taking into consideration the influence brought by creep and relaxation. It is found that AAS and AASF concrete showed lower autogenous shrinkage-induced stress and later cracking compared to ordinary Portland cement (OPC) based concrete with similar compressive strength, despite the higher autogenous shrinkage of AAS and AASF concrete. The low autogenous shrinkage-induced stress in the AAC is mainly attributed to the pronounced stress relaxation. A good prediction of the stress evolution in AAC is obtained by taking into account the elastic part of the autogenous shrinkage and the stress relaxation. In contrast, calculations ignoring the creep and relaxation would lead to a significant overestimation of the stress in AAC.

这项研究的目的是研究受约束的自发收缩的碱活化矿渣（AAS）和碱活化矿渣粉煤灰（AASF）混凝土的开裂潜力。温度应力测试机（TSTM）首次用于在约束条件下监测应力变化并测量碱活化混凝土（AAC）的开裂时间。根据试验结果计算了AAS和AASF混凝土中的应力，同时考虑了蠕变和松弛带来的影响。发现与具有相似抗压强度的普通波特兰水泥（OPC）基混凝土相比，AAS和AASF混凝土表现出更低的自收缩引起的应力和开裂，尽管AAS和ASF混凝土的自收缩较高。AAC中自发收缩引起的低应力主要归因于明显的应力松弛。通过考虑自生收缩的弹性部分和应力松弛，可以很好地预测AAC中的应力演化。相反，忽略蠕变和松弛的计算将导致AAC中应力的明显高估。