By simulating the high temperature surrounding rock tunnel conditions, the impact of mineral admixture on compressive strength was studied. The results show that the high temperature surrounding rock condition can improve the early strength of the concrete, but later strength decreases significantly. When the temperature is below 50 ℃ , slag-fly ash composite concrete has higher strength; when the temperature exceeds 60 ℃ , the strength of fly ash concrete is higher. The analysis of XRD and SEM show that the hydration rate of binder speeds up under high temperature surrounding rock condition, so the hydration products generate too quick to evenly spread, mutual overlap gets worse. When the temperature is below 50 ℃ , evaporation of water is slow and moisture is adequate so the slag is more likely to be activated and the structure of hydration products is denser; when the temperature exceeds 60 ℃ , the water evaporating faster, slag is difficult to be activated, the structure of hydration products becomes loose.%通过模拟高岩温隧道条件,研究了高岩温隧道条件下矿物掺合料对混凝土强度的影响.结果表明:高岩温条件下可以提高混凝土的早期强度,但后期强度却有较大幅度的下降,当温度低于50℃时,矿渣粉煤灰复合混凝土的强度更高；当温度超过60℃时,粉煤灰混凝土的强度更高.XRD及SEM分析表明:高岩温条件下胶凝材料水化速度加快,生成的水化产物来不及均匀扩散,相互搭接变差,当温度低于50℃时,水分蒸发较慢,水分充足,矿渣的活性容易被激发,水化产物结构致密；当温度超过60℃时,由于水分蒸发较快,矿渣的活性难以被激发,水化产物结构变疏松.
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