Currently, fire in building is one of the most serious disasters. With the increase of basic construction items in western China, ordinary medium sand resource no longer met with the need of engineering. Compressive strength experiments of concrete produced with desert sand after elevated temperature were carried out in this paper. The effects of desert sand replacement rate (DSRR), temperature and cooling regime on the mechanical performances of concrete produced with desert sand were analyzed. XRD and SEM experiments were also conducted to study the microstructure of concrete produced with desert sand after elevated temperature. Experimental results showed that the cubic compressive strength of concrete produced with desert sand increased firstly, and then declined with temperature. Whereas, the prismatic compressive strength and elasticity modulus of concrete produced with desert sand under static compression declined with temperature. With the enhancement of DSRR, the elasticity modulus under static compression, cubic compressive strength and prismatic compressive strength of concrete produced with desert sand after elevated temperature increased firstly, and then declined, the maximum value of which was reached when DSRR amounted to 40%. Regression models were established to predict the mechanical performances of concrete produced with desert sand after elevated temperature, which were in good agreement with experimental results.

中文翻译：

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高温后沙漠砂混凝土的力学性能

目前，建筑火灾是最严重的灾害之一。随着西部地区基础建设项目的增加，普通中砂资源已不能满足工程需要。本文对沙漠砂混凝土进行了高温后抗压强度试验。分析了沙漠砂置换率（DSRR）、温度和冷却方式对沙漠砂混凝土力学性能的影响。还进行了 XRD 和 SEM 实验以研究高温后用沙漠砂生产的混凝土的微观结构。试验结果表明，沙漠砂混凝土的立方抗压强度随着温度的升高先增大后减小。然而，沙漠砂在静态压缩下生产的混凝土的棱柱形抗压强度和弹性模量随着温度的升高而下降。随着DSRR的提高，沙漠砂高温后混凝土静压弹性模量、立方抗压强度和棱柱形抗压强度先升高后降低，当DSRR达到40%时达到最大值。建立了回归模型来预测高温后沙漠砂混凝土的力学性能，与实验结果吻合较好。高温后沙漠砂混凝土的立方抗压强度和棱柱抗压强度先升高后降低，当DSRR达到40%时达到最大值。建立了回归模型来预测高温后沙漠砂混凝土的力学性能，与实验结果吻合较好。高温后沙漠砂混凝土的立方抗压强度和棱柱抗压强度先升高后降低，当DSRR达到40%时达到最大值。建立了回归模型来预测高温后沙漠砂混凝土的力学性能，与实验结果吻合较好。