再生砖骨料多孔混凝土微观结构及结构模型

为了深入研究再生砖骨料多孔混凝土的微观结构,从本质上认识其性状及规律,引入扫描电镜研究再生砖骨料多孔混凝土界面过渡区微观形貌；根据混凝土中心质假说分析概括再生砖骨料多孔混凝土结构模型，定性研究微观结构与宏观性能的关系，探索界面过渡区形貌和骨料大中心质效应对再生砖骨料多孔混凝土宏观性能的影响。结果发现再生砖骨料多孔混凝土具有较好的界面过渡区结构，结构密实，水化产物丰富，水灰比、目标孔隙率、养护龄期，矿物掺料对结构的密实程度和水化产物的类型、数量有一定影响，进而影响强度。多孔混凝土存在较多负中心质效应，大中心质只有再生砖骨料。今后应当把研究负中心质效应作为重点。

Experimental studies on microstructure and structure model for recycled brick aggregate porous concrete

In order to further study the microstructures and essentially understand the characteristics and rules of the recycled brick aggregate porous concrete, during the microscopic studies of the recycled brick aggregate porous concrete, the modern microscopic test equipment-scanning electron microscopy (SEM) is applied to the research of the microstructures of the cement-stone-recycled brick aggregate porous concrete. And according to the assumption of central grains developed by Professor WU Zhong-wei，the authors have analyzed and summarized the structure model for the recycled brick aggregate porous concrete, and have done qualitatively researches of the relationships between the microstructures and the macroscopic strength behavior, and then explored the morphology of ITZ (interface transition zone) and the impacts of aggregates large center mass effect on the macroscopic properties of the recycled brick aggregate porous concrete. Analysis results show that the recycled brick aggregate porous concrete has better interfacial transition zone structure， the structure is very compact and the hydration products are very rich. Water cement ratio, design porosity, maintenance period and permeability reducing admixture all have a certain effect on the compactness of the structure and the type as well as the quantity of the hydration products, and on the strength of the concrete structures. There are a lot of negative center mass effects in the porous concrete and the large center mass is only in the recycled brick aggregate. Studies of the negative center mass effect should be taken as a key issue in the future.