建筑垃圾砖粉颗粒特征对胶凝材料体系密实填充效应的影响

Compaction Filling Effect of Construction Waste Brick Powder on Cementitious Material

利用Andreasen模型,研究了砖粉、硅灰对胶凝材料体系密实填充效应的影响,并基于微观结构,进一步分析了砖粉、硅灰对水泥基材料内部结构密实度的影响规律。研究表明,硅灰与较细砖粉的颗粒细度均小于水泥,主要表现为<20μm颗粒含量的增多及>40μm颗粒含量的降低。硅灰、较细砖粉可在一定程度上改善胶凝材料体系的密实填充性能,进而提高水泥基材料的宏观及微观性能。但是由于砖粉、硅灰颗粒级配不合理,导致水泥-砖粉、水泥-硅灰-砖粉颗粒在整个颗粒粒径范围内无法形成最紧密堆积。因此,在生产砖粉等建筑垃圾再生微粉时,应对砖粉等再生微粉的颗粒群分布进行控制,使胶凝材料体系形成最紧密堆积;较细砖粉及硅灰主要通过改善砂浆内部结构密实度、水化产物种类、数量以及界面过渡区结构进而改善性能。

The influence of brick powder and silica fume on the compactness of cementitious material system was studied based on the Andreasen model.Based on the microscopic analysis method,the influence law of brick powder and silica fume on the structure compactness of cementitious material system was analyzed.The results show that the particle fineness of silica fume and fine brick powder is smaller than that of cement,which is mainly reflected in the increase of<20μm particle content and the decrease of>40μm particle content.The silica fume and fine brick powder can improve the compacting properties of cementitious material system,so as to improve the properties of cementitious materials.However,due to the unreasonable particle size distribution of brick powder and silica fume,the cement-brick powder and cement-silica fume-brick powder particles cannot form compact packing in the whole particle size range.Therefore,it is necessary to further control the particle distribution of regenerated powder such as brick powder to make the cementitious material system form a compact stacking state.The fine brick powder and silica fume can improve the internal structure density,the type and quantity of hydration products and the structure of interfacial transition zone,and then improve the macroscopic performances.