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为了阐明碳化与氯盐复合作用下硬化水泥浆体的微结构,基于X射线计算机断层扫描成像(X-CT)和电子探针微区分析(EPMA)技术探明了氯盐对水泥浆体碳化速率的影响,测定了碳化作用下水泥浆体内Cl、S和Na元素的浓度分布。结果表明:氯盐可细化养护龄期为28d的水泥浆体孔结构,提高其密实度并减缓碳化速度;碳化作用下水泥浆体的碳化区易出现裂缝,二氧化碳气体通过这些裂缝扩散到水泥浆体内部进行碳化,致使水泥浆体碳化深度不均匀;碳化过程中Cl、S和Na元素向非碳化区迁移和浓缩,初始均匀分布的元素在碳化区含量减少,在非碳化区含量升高。所得结论为混凝土结构耐久性设计提供科学的理论依据。
In order to elucidate the microstructure of hardened cement paste under the combined effect of carbonization and chloride salt, the effect of chloride salt on the carbonization of cement paste based on X-ray computed tomography (X-CT) and electron probe microanalysis (EPMA) The effect of carbonation on the concentration distribution of Cl, S and Na in the cement slurry was measured. The results show that the chloride salt can refine the pore structure of cement slurry with the curing age of 28d, increase its densification and slow down the carbonization rate. Cracks easily occur in the carbonization zone of the cement slurry under carbonation, and carbon dioxide gas diffuses into the slurry through these cracks In the carbonization process, the depth of carbonization of the cement paste is not uniform. In the carbonization process, the elements Cl, S and Na migrate and concentrate to the non-carbonation zone. The content of the initial uniform distribution decreases in the carbonation zone and increases in the non-carbonation zone. The conclusions obtained provide a scientific theoretical basis for the durability design of concrete structures.