骨料种类对混凝土孔结构及微观界面的影响

Influence of Aggregate Variety on Pore Structure and Microscopic Interface of Concrete

基于RapidAir和MAP-BEI测试技术,对比研究了分别以玄武岩、砂岩和灰岩为人工骨料的大坝混凝土内部孔结构及界面特征.结果表明:配合比一定时,灰岩混凝土气泡数量最多,间距系数和平均孔径最小;砂岩混凝土气泡数量最少,间距系数和平均孔径最大,工程中应予以足够重视.界面Ca(OH)2的富集程度受骨料化学属性及物理性能(如长期吸水率)影响.上述3种骨料-浆体界面Ca(OH)2的富集程度为砂岩>玄武岩>灰岩,界面过渡区厚度为砂岩>灰岩>玄武岩,砂岩界面性能最薄弱.

Based on the test technique of RapidAir and MAP-BEI,pore structure and microscopic interface of dam concrete with different aggregates were studied.The results show that with the definite mix proportion,the limestone concrete has the maximum amount of bubbles and the minimum space coefficient and average pore size,while the sandstone concrete leads to the opposite results,which should be paid enough attention.The enrichment of Ca（OH）2in the interfacial transition zone（ITZ）is affected by chemical and physical properties of aggregates（such as long-term water absorption）.The degree of Ca（OH）2enrichment and interface thickness are increased in the order of sandstone〉basalt〉limestone and sandstonelimestonebasalt.Sandstone concrete has the weakest interface structure.