冻融-碳化耦合环境下自燃煤矸石混凝土耐久性实验研究

为研究冻融-碳化耦合环境下自燃煤矸石混凝土耐久性能,通过冻融-碳化与碳化-冻融2种耦合环境实验,分析其质量、动弹性模量、抗压强度及碳化深度等损失特性,揭示冻融-碳化耦合环境作用机理。结果表明:冻融-碳化环境下质量、相对动弹性模量损失率均与循环次数、水灰比呈正相关;小于63次,碳化-冻融环境劣化其质量能力强于冻融-碳化环境;超过63次,冻融-碳化环境劣化能力强于碳化-冻融环境;冻融-碳化环境劣化动弹性模量能力高于碳化-冻融环境。初期碳化反应在一定程度上能促进强度增长,但冻融100次且碳化14 d后,冻融-碳化环境下强度损失率与水灰比呈正相关。冻融-碳化环境下碳化深度与时间、水灰比呈正相关,冻融环境是加速其碳化腐蚀的催化剂,碳化-冻融环境劣化碳化深度强于冻融-碳化环境,2种耦合环境碳化差值0.87~2.10 mm。为深入研究煤矸石混凝土在复杂环境中的耐久性提供参考。

Experimental study on durability of self-ignite coal gangue concrete under freeze-thaw and carbonization coupling environment

Loss properties, through freeze-thaw and carbonization coupling or carbonization and freeze-thaw coupling environment tests, such as mass, dynamic elastic modulus, compressive strength, and carbonization depth were analyzed in order to investigate the durability of self-igniting coal gangue concrete under freeze-thaw and carbonization coupling environments, the mechanism of which was revealed. It was suggested that under freeze-thaw and carbonization coupling environments, the loss rate of mass and that of dynamic elastic modulus are positively related to the cycle number as well as the water cement ratio. The rate of mass reduction under carbonization and freeze-thaw coupling is higher than that under freeze-thaw and carbonization coupling with less than 63 cycles, while the result is quite the opposite with more than 63 cycles, and the loss rate of dynamic elastic modulus under freeze-thaw and carbonization environments is higher than that under carbonization and freeze-thaw environments. Carbonization reactions, in the initial stage, can promote the increase in compressive strength to some extent, but the strength loss rate, after 100 freeze-thaw cycles along with 14 days of carbonization, has a positive correlation with the water cement ratio under freeze-thaw and carbonization environments. The carbonization depth is positively related to both time and water cement ratio under freeze-thaw and carbonization environments. In addition, a freeze-thaw environment is a catalytic agent that can accelerate the process of carbonization corrosion. The carbonization depth under carbonization and freeze-thaw environments is deeper than that under freeze-thaw and carbonization environments, thus causing a difference value that varies from 0.87 to 2.10 mm. The research results provide an important reference for further exploration of the durability of coal gangue concrete in a complex environment.