纤维尾矿砂再生混凝土基本力学性能及计算方法  

Investigation on properties of recycled concrete mixed with tailing sand and polypropylene fiber

作　　者：张少峰[1,2] 牛荻涛[2,3] ZHANG Shaofeng;NIU Ditao(Shaanxi Railway Institute,Weinan 714000,China;School of Civil Engineering,Xi′an University of Architecture and Technology,Xi′an 710055,China;State Key Laboratory of Green Building in Western China,Xi′an University of Architecture and Technology,Xi′an 710055,China)

机构地区：[1]陕西铁路工程职业技术学院,陕西渭南714000 [2]西安建筑科技大学土木学院,陕西西安710055 [3]西安建筑科技大学省部共建西部绿色建筑国家重点实验室,陕西西安710055

出　　处：《混凝土》2023年第9期7-12,15,共7页Concrete

基　　金：国家自然科学基金(52078413);中青年科技创新人才计划(KJRC201903);2020渭南市基础研究项目(ZDYF-SFGG-92)。

摘　　要：通过钢-聚丙烯混杂纤维增强尾矿砂再生混凝土的抗压与劈裂强度试验,研究了尾矿砂替代率、混杂纤维掺量、纤维种类对再生混凝土抗压强度和劈裂强度的影响。根据抗压强度、劈裂强度及水泥水化产物的胶体结构,分析纤维尾矿砂再生混凝土的破坏机制和增强机制。研究表明:尾矿砂替代率为20%时,各龄期再生混凝土的抗压强度和劈裂强度提高了2%~5%和2%~8%;适量尾矿砂改善再生混凝土力学性能的机理在于其优化细骨料的颗粒级配,改善内部孔隙结构,提高基体密实度;当钢-聚丙烯纤维的体积掺量分别为1.5%和0.6%时,各龄期尾矿砂再生混凝土的抗压强度和劈裂强度提高了12%~15%和20%~32%;混杂纤维通过纤维框架增强效应改善基体的力学力学性能,并基于孔隙特征、破坏形态和纤维微观形貌,分析其增强机制;最后,提出考虑尾矿砂掺量、纤维种类和掺量等因素的抗压强度计算方法。The effects of replacement ratio of tailing sand,fiber volume content and fiber types on the compressive strength and splitting strength of steel-polypropylene hybrid fiber reinforced recycled aggregates concrete were investigated through compressive and splitting strength test.According to the results and SEM image of steel-polypropylene hybrid fiber reinforced recycled aggregates concrete,the failure mechanism and reinforced mechanism were analyzed.The results showed that the compressive and splitting strength was improved by 2%~5%and 2%~8%with the tailing sand content of 20%at all curing age.The tailing sand increased mechanism was that a proper amount of tailing sand could optimize the particle gradation of fine aggregate and the internal pore structure,leading to a high compactness.When the content of steel and polypropylene hybrid fiber were 1.5%and 0.6%,the compressive and splitting strength was improved by 12%~15%and 20%~32%at all curing age.The reinforcement mechanism were improved by the reinforcement effect of fiber frame and was analyzed based on the pore characteristic,failure morphology and fiber microstructure.

关 键 词：尾矿砂再生混凝土 混杂纤维 力学性能 计算方法 

分 类 号：TU528.01[建筑科学—建筑技术科学]