煤矸石粗集料混凝土抗碳化性能研究

发布时间：2018-02-25 18:47

本文关键词： 煤矸石水灰比碳化深度碳化模型扫描电镜　出处：《建筑材料学报》2017年05期 　论文类型：期刊论文

【摘要】：探究了水灰比(质量比)、煤矸石粗集料掺量(质量分数)、碳化时间以及煤矸石粗集料是否煅烧等对煤矸石粗集料混凝土抗碳化性能的影响规律,借助扫描电镜分析了煅烧与未煅烧煤矸石粗集料混凝土微观结构对其抗碳化性能的影响机理,建立了适用于不同水灰比、煤矸石粗集料掺量以及碳化时间下的多参数混凝土碳化模型,并将碳化模型在隧道工程结构的耐久性设计中进行了应用.结果显示:煅烧与未煅烧煤矸石粗集料混凝土的碳化深度均随煤矸石粗集料掺量增加而增大,且均与煤矸石粗集料掺量和碳化时间的平方根呈线性正相关;在低水灰比(0.35)时,煅烧煤矸石粗集料混凝土抗碳化性能明显优于未煅烧煤矸石粗集料混凝土.扫描电镜显示,煅烧煤矸石粗集料混凝土内部结构比未煅烧煤矸石粗集料混凝土更密实,二氧化碳的渗入通道减少;在进行隧道工程结构耐久性设计时泵送混凝土中未煅烧煤矸石粗集料的掺量不应大于25%.研究结果为煤矸石粗集料混凝土的抗碳化性能分析及其工程应用提供了理论依据.
[Abstract]:The effects of water-cement ratio (mass ratio), coal gangue coarse aggregate content (mass fraction), carbonation time and whether coal gangue coarse aggregate is calcined on the carbonation resistance of coal gangue coarse aggregate concrete are studied. The influence mechanism of microstructure of calcined and uncalcined coal gangue coarse aggregate concrete on its carbonation resistance was analyzed by means of scanning electron microscope, and suitable for different water-cement ratio was established. Multi-parameter concrete carbonization model with coal gangue coarse aggregate content and carbonation time, The carbonation model is applied to the durability design of tunnel structure. The results show that the carbonation depth of calcined and uncalcined coarse aggregate concrete increases with the increase of the content of coarse aggregate. There was a linear positive correlation between the content of coarse coal gangue aggregate and the square root of carbonation time, and the carbonation resistance of calcined coal gangue coarse aggregate concrete was obviously better than that of uncalcined coal gangue coarse aggregate concrete at low water-cement ratio of 0.35). Scanning electron microscope showed that the carbonation resistance of calcined coal gangue coarse aggregate concrete was better than that of uncalcined coal gangue coarse aggregate concrete. The internal structure of calcined coal gangue coarse aggregate concrete is more dense than that of uncalcined coal gangue coarse aggregate concrete, and the carbon dioxide infiltration channel is reduced. In the durability design of tunnel structure, the content of raw aggregate of uncalcined coal gangue in pumping concrete should not be greater than 250.The results provide a theoretical basis for the analysis of carbonation resistance of coarse aggregate concrete of coal gangue and its engineering application.
【作者单位】：中国矿业大学(北京)力学与建筑工程学院;江苏科技大学土木工程与建筑学院;
【基金】：国家自然科学基金资助项目(51578539) 北京市自然科学基金资助项目(8164061)
【分类号】：TU528

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