颗粒级配对水泥基材料有害孔隙率的影响

水泥基材料的硬化浆体中含有大量的孔隙 ,其中的有害孔隙直接影响到耐久性 .依据所建立的微粒级配模型 ,采用粉煤灰、硅灰等球形颗粒掺合料及纳米纤维红粉 (NR)掺合料 ,设计球形颗粒紧密堆积体系与纳米纤维增强紧密堆积体系 ,讨论 2种混合体系内部的总孔隙率与有害孔隙率之间的关系 ,确定活性NR粉在水泥基材料中的作用 .研究表明 ,NR粉能够增加体系密实度 ,水泥混合体系硬化后期的总孔隙率与有害孔隙率之间服从对数关系 ,通过微粒级配模型可预知体系有害孔隙率及颗粒级配的合理性 .

Relation of Grain Grading and Deleterious Porosity of Cement-based Materials

In the hardened paste of cement-based materials,there are large amount of porosities,among which the deleterious ones may directly affect the durability of materials.According to the grain grading mathematical model of cement-based materials established in this thesis,we designed the global grading system and the nano-fiber reinforced system by using the global grain admixtures such as fly ash,silica fume,and nano-fiber admixture such as nano-fiber red (NR) powder.By discussing the relationship of deleterious porosity and the total porosity of hardened cement paste,we managed to determine the positive role that NR powder plays in cement-based materials.Research results show that NR powder can increase the density of cement-based materials,the relationship of deleterious porosity and the total porosity of hardened cement paste accords with logarithmic curve and deleterious porosity of the system,and rationality of the grain grading of the system can be roughly forecasted through calculating the density of mixture system.