【作者】 王浩；

【导师】 蒋华；

【作者基本信息】 西华大学 ， 结构工程， 2017， 硕士

【摘要】 随着我国建筑业的飞速发展,建筑材料的需求量不断增加,大量的自然资源被开采,生态环境遭到破坏。从房屋的新建到拆除,各个环节都会产生大量的建筑垃圾,这些建筑垃圾中比重最大的是废弃混凝土。大量试验研究表明,废弃的混凝土块经过适当的处理以后,部分或全部替代混凝土用砂石等天然集料（主要是粗骨料）,可以配置成的新混凝土。但是和天然骨料配置而成的混凝土相比,再生混凝土的脆性表现得更加明显,抗裂性能明显降低,构件在受弯时会产生较大的挠度和裂缝宽度,且不利于结构的抗震性能,所以目前普遍用于路基、路面工程中。为了解决再生混凝土结构抗震性能低、抗裂性差的这一缺点,可以将型钢和钢纤维加入再生混凝土中。本试验制作了8根试验梁,设置钢纤维的体积率和再生骨料的取代率两个基本变量,通过对加载过程中梁的挠度、裂缝、混凝土应变、钢筋应变、工字钢应变结构混凝土力学性能试验等数据的分析,研究以下两方面的内容:1、在相同骨料取代率（100%）的情况下,不同体积率的钢纤维（0,0.5%,1%,1.5%,2%）对组合梁的抗弯性能的影响;2、在相同钢纤维体积率（1%）的情况下,不同再生骨料的取代率（0,50%,100%）对组合梁的抗弯性能的影响。最终得出的主要结论如下:（1）钢纤维-型钢再生混凝土梁的受弯机理与普通型钢混凝土梁基本相同,基本满足平截面假定;（2）根据混凝土力学性能试验,通过数据分析得到钢纤维体积率、再生骨料取代率γ与钢纤维再生混凝土轴心抗压强度的关系式,其中为不加钢纤维的普通混凝土轴心抗压强度:f_frck=（0.9576 + 0.1310 γ + 9.36）fck（3）全部使用再生骨料的情况下,钢纤维的适量加入能明显改善混凝土梁的抗裂性能。钢纤维体积率和再生骨料取代率对组合梁的承载力有一定的影响,但并不明显。更多还原

【Abstract】 With the rapid development of China’s architecture industry,the increasing demand for building materials leads to the mining of vast natural resources,which consequently results in the destruction of ecological environment.A lot of construction waste will be generated in all the links of architecture industry ranging from construction to demolition of buildings.A lot of experimental studies have shown that all or part of the abandoned concrete blocks,after being appropriately treated,may replace the sand and gravels and other natural aggregates（mainly coarse aggregates）in concrete for re-configuring new concrete.However,compared with natural aggregate concrete,recycled aggregate concrete shows more obvious brittleness,as well as obviously declined anti-cracking capacity,which may cause bigger deflection and crack width of a flexural member and is disadvantageous to the seismic performance of a structure.,such as,used as building foundation bed,road base,etc.In order to solve the problem of low performance and poor crack resistance of recycled concrete structure,steel and steel fiber can be added into recycled concrete.In this test,we produced 8 test beams and set 2 basic variables,namely,the volume fraction of steel fiber and the replacement rate of recycled aggregate.The study covers the following items:1.The impact of steel fiber with various volume fractions（0,0.5%,1%,1.5%,2%）on the flexural behavior of composite beams under the premise of same aggregate replacement rate（100%）;2.The impact of recycled aggregates with various replacement rates（0,50%,100%）on the flexural behavior of composite beams under the premise of same volume fraction of steel fiber（1%）;Based on analysis of data collected during the loading process,such as beam deflection,cracks,concrete strain,rebar strain,I-bar strain,and mechanical property tests of structural concrete,major conclusions are obtained:（1）The bending mechanism for recycled aggregate concrete beams with steel fiber-profile steel is basically the same as that for the ordinary steel reinforced concrete beams.（2）The relationship among the volume ratio of steel fiber,the replacement ratio of recycled aggregateγ,and the axial compressive strength of steel-fiber recycled aggregate concrete is obtained based on mechanical property tests of concrete,as well as on the data analysis,as shown below,where,is the axial compressive strength of ordinary concrete without steel fiber.f_frck=（0.9576 + 0.1310 γ + 9.36）fck（3）Under the condition that only recycled aggregate is applied,steel fiber with volume ratio of 1%-1.5% can obviously improve anti-cracking performance of beams.The volume ratio of steel fiber and the replacement ratio of recycled aggregate have certain unremarkable influences on the load-bearing capacity of composite beams.更多还原