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.
To explore the influence of water cement ratio,coal gangue coarse aggregate content（by mass）,carbonization time and whether or not coal gangue coarse aggregate were calcined on the carbonation resistance of coal gangue aggregate concrete.The microstructure of calcined and non-calcined coal gangue coarse aggregate concrete and the mechanism of its influence on carbonization were clarified by means of the scanning electron microscope（SEM）.A multi parameter concrete carbonation model was established,which was suitable for different water cement ratio,coal gangue coarse aggregate content and carbonation time.The carbonation model was applied in the durability design of tunnel engineering structure.The results show that the carbonation depth of calcined and non-calcined coal gangue coarse aggregate concrete increases with the increase of coal gangue coarse aggregate content,and it is linearly positive with the square root of coal gangue coarse aggregate and carbonization time.With low water cement ratio（such as 0.35）,anti-carbonization performance of calcined coal gangue coarse aggregate concrete is more significant than non-calcined coal gangue coarse aggregate concrete.SEM study shows that the calcined coal gangue coarse aggregate concrete internal structure is denser than the non-calcined coal gangue coarse aggregate concrete,which reduces the infiltration of carbon dioxide.The non-calcined coal gangue coarse aggregate content in the pumping concrete should not be greater than 25% when the durability design of the tunnel structure.The research provides a theoretical basis for the anti-carbonation performance analysis and engineering application of coal gangue coarse aggregate concrete.
出处
《建筑材料学报》
EI
CAS
CSCD
北大核心
2017年第5期787-793,共7页
Journal of Building Materials
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)
关键词
煤矸石
水灰比
碳化深度
碳化模型
扫描电镜
coal gangue
water cement ratio
carbonization depth
carbonization model
scanning microscope
