纤维与纳米粘土改性石灰土劈裂强度特性研究  

Splitting Strength of Fiber and Nano-clay Modified Lime Soil Characteristic Research

作　　者：张伟清 ZHANG Weiqing(Guangdong Architectural Design&Research Institute Co.,Ltd.Guangzhou 510010,China)

机构地区：[1]广东省建筑设计研究院有限公司,广州510010

出　　处：《广东土木与建筑》2023年第7期115-118,共4页Guangdong Architecture Civil Engineering

摘　　要：利用聚丙烯纤维和纳米粘土改性石灰土,对纤维改性石灰土(FLS)、纳米粘土改性石灰土(NLS)和纤维纳米粘土复合改性石灰土(NFLS)的力学性能进行研究。通过对FLS、NLS和NFLS进行劈裂试验,探究其28 d龄期下的劈裂抗拉强度特征,并用能量耗散理论进一步说明纤维和纳米粘土对NFLS劈裂抗拉破坏的作用机理。研究结果表明:(1)聚丙烯纤维和纳米粘土能够显著提高石灰土的劈裂抗拉强度。NLS和FLS的劈裂抗拉强度在纳米粘土掺量为8%和纤维掺量为1%条件下较LS提升129%和169%。(2)纳米粘土可促进石灰土发生火山灰反应生成C-S-H和C-A-H等胶凝材料,纤维通过拉结界面作用提高其延性,两者复合改性进一步提高石灰土的劈裂抗拉强度。(3)NFLS的耗散能与其劈裂抗拉强度基本一致,可进一步说明在劈裂过程裂缝发展的损伤破坏对NFLS的影响。聚丙烯纤维和纳米粘土复合改性可提高改性石灰土的延性和劈裂抗拉强度。The mechanical properties of fiber modified lime soil(FLS),nanoclay modified lime soil(NLS)and fiber nanoclay compos‐ite modified lime soil(NFLS)were studied by using polypropylene fiber and nanoclay modified lime soil.Through splitting tests of FLS,NLS and NFLS,the splitting tensile strength characteristics at 28 d age were investigated,and the mechanism of fiber and nanoclay on split‐ting tensile failure of NFLS was further explained by energy dissipation theory.The results show that:①Polypropylene fiber and nanoclay can significantly improve the splitting tensile strength of lime soil.The splitting tensile strength of NLS and FLS is 129%and 169%higher than that of LS with 8%nano-clay and 1%fiber.②Nano-clay can promote the formation of C-S-H and C-A-H by pozzolanic reaction of limestone soil.The ductility of nano-clay fiber is improved by pulling the interface,and the splitting tensile strength of limestone soil is fur‐ther improved by the composite modification.③The dissipated energy of NFLS is basically consistent with its splitting tensile strength,which can further illustrate the influence of damage and failure of crack development on NFLS during splitting process.The composite modi‐fication of polypropylene fiber and nano-clay can improve the ductility and splitting tensile strength of modified lime soil.

关 键 词：石灰土 聚丙烯纤维 纳米粘土 劈裂抗拉强度 耗散能 

分 类 号：TU432[建筑科学—岩土工程]