首页|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

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

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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.
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.

coal ganguenano-SiO2PPFconcretemechanical propertiesmicroscopic characteristics

姚贤华、郭晓宁、韩瑞聪、管俊峰、李焕

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华北水利水电大学 土木与交通学院,郑州 450045

郑州三和水工机械有限公司,郑州 450121

煤矸石骨料 纳米SiO2 聚丙烯纤维 混凝土 力学性能 微观特征

国家自然科学基金面上项目河南省杰出青年科学基金华北水利水电大学水利工程创新型科技团队培育计划河南省科技攻关项目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

521791322323004210162023SZ1001000842321023201842021KFKT-10

2024

10.13801/j.cnki.fhclxb.20230714.005

复合材料学报
北京航空航天大学 中国复合材料学会

复合材料学报

CSTPCD北大核心
影响因子：0.933
ISSN：1000-3851
年,卷(期)：2024.41(3)
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