纳米SiO_(2)改性再生建筑矿物微粉性能研究

Research on Properties of Nano-SiO_(2)Modified Regenerated Building Mineral Micropowder

通过破碎粉磨废旧混凝土制备了再生建筑矿物微粉,研究了纳米SiO_(2)对掺再生微粉水泥标准稠度和凝结时间、胶砂抗折和抗压强度、化学结合水生成量的影响,并对混凝土性能进行测试。试验结果表明:再生微粉取代水泥后水泥标准稠度降低、凝结时间延长,掺入纳米SiO_(2)的胶凝体系水泥标准稠度增加,凝结时间缩短;适量纳米SiO_(2)能够改善再生微粉掺量增加对水泥抗折和抗压强度的不良影响,且提高了水泥化学结合水生成量,对7 d水泥水化程度影响相对明显;纳米SiO_(2)有利于掺再生微粉混凝土力学和耐久性能提高,但应注意掺量控制。研究表明,纳米SiO_(2)改性再生建筑矿物微粉技术可行。

Regenerated building mineral micropowder was prepared by crushing and grinding,and the effects of nano SiO_(2)on the standard consistency and setting time of cement mixed with recycled micropowder,flexural and compressive strength of mortar,chemical binding water content were studied.The performance of concrete was tested,and the results showed that after replacing cement with recycled micropowder,the standard consistency of cement decreased,the setting time extended,and the standard consistency of cement system mixed with nano SiO_(2)increased,while the setting time shortened.An appropriate amount of nano SiO_(2)can improve the adverse effects of increasing the amount of recycled micro powder on the flexural and compressive strength of cement,and increase the chemical binding water content of cement,which has a relatively significant impact on the hydration degree of cement after 7 days.Nano SiO_(2)is beneficial for improving the mechanical and durability properties of recycled micro powder concrete,but attention should be paid to controlling the dosage.Research has shown that the technology of nano SiO_(2)modified regenerated building mineral powder is feasible.