纳米SiO2和聚丙烯纤维对全煤矸石骨料混凝土力学性能与微观结构的影响
Effect of nano-SiO2 and polypropylene fibers on the mechanical properties and microscopic properties of all coal gangue aggregate concrete
姚贤华 1郭晓宁 1韩瑞聪 1管俊峰 1李焕2
作者信息
- 1. 华北水利水电大学 土木与交通学院,郑州 450045
- 2. 郑州三和水工机械有限公司,郑州 450121
- 折叠
摘要
煤矸石作为工业固体废弃物,替换全部骨料制备混凝土,是对煤矸石二次利用的有效途径.本文将破碎后的煤矸石骨料替换混凝土全部粗细骨料,利用不同掺量的纳米SiO2 和聚丙烯纤维(PPF)对其改性,通过宏观力学和微观分析相结合的方法,研究了纳米SiO2 和PPF单独作用与复合作用下对混凝土力学性能、微观结构的影响.研究结果表明,纳米SiO2 与PPF复掺,其掺量分别为 1.5wt％与 0.6 kg·m-3 时混凝土的性能最好.与对照组相比,龄期为 7天时,混凝土抗压强度、抗折强度和抗劈裂强度分别提高 21.8％、43.5％和 44.4％;龄期为 28天时,其抗压强度、抗折强度和劈裂强度分别提高 20％、44.9％和 43.6％.微观结构分析表明,煤矸石混凝土孔隙率减少,水化过程加速,混凝土中大孔的分形维数从 2.9975提高至 2.9990,而小孔的分形维数从 2.9852降低至 2.9827,小孔分形维数降低,大孔的分形维数增加,使空间填充能力越强,内部孔隙越少.
Abstract
Coal gangue as industrial solid waste,replacing all aggregates to produce concrete,is an effective way to reuse coal gangue.In this paper,all the coarse and fine aggregates of concrete were replaced by crushed coal gangue aggregate,and modified by different amounts of nano-SiO2 and polypropylene fiber(PPF).Based on the combination of macro mechanics and micro analysis,the effects of the single and combined action of nano-SiO2 and PPF on the mechanical properties and microstructure of concrete were studied.The results show that the per-formance of concrete is the best when the mixture of nano-SiO2 and PPF is 1.5wt％and 0.6 kg·m-3,respectively.Compared with the control group,the compressive strength,flexural strength and splitting strength of the concrete at 7 days increase by 21.8％,43.5％and 44.4％,respectively.Besides,the compressive strength,flexural strength and splitting strength at 28 days increase by 20％,44.9％and 43.6％,respectively.The microstructure analysis shows that the porosity of coal gangue concrete decreases,the hydration process is accelerated,the fractal dimension of large holes of the concrete increases from 2.9975 to 2.9990,while that of small holes decreases from 2.9852 to 2.9827,the fractal dimension of small holes decreases,and the fractal dimension of large holes increases,so that the stronger the space filling capacity,the fewer internal pores.
关键词
煤矸石骨料/纳米SiO2/聚丙烯纤维/混凝土/力学性能/微观特征Key words
coal gangue/nano-SiO2/PPF/concrete/mechanical properties/microscopic characteristics引用本文复制引用
基金项目
国家自然科学基金面上项目(52179132)
河南省杰出青年科学基金(232300421016)
华北水利水电大学水利工程创新型科技团队培育计划(2023SZ100100084)
河南省科技攻关项目(232102320184)
西安理工大学省部共建西北旱区生态水利国家重点实验室(2021KFKT-10)
出版年
2024
NETL
NSTL
万方数据