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本实验研究基于C30混凝土在粗骨料取代率为50%下掺入不同种类的纤维后,再生混凝土的主要力学性能。选择掺入的纤维有钢纤维、玻璃纤维、聚丙烯纤维。再生粗骨料选择龄期为40年的废弃建筑物混凝土。制作粗骨料取代率为50%再生混凝土标准土立方体试块(150 mm×150 mm×150 mm),标准棱柱体试块(150 mm×150 mm×300 mm),尺寸为150 mm×150 mm×550 mm试块。每种尺寸下制作3组试块。在三种试块的制备过程中分别加入钢纤维、玻璃纤维、聚丙烯纤维,观察其流动性、塌落度、保水性。入模后按混凝土标准实验的养护方法放置于养护室中养护28 d后测试其抗压强度、抗折强度、劈裂抗拉强度。对所得结论进行比较分析后得知在相同粗骨料取代率下对于掺入不同纤维的再生混凝土,其表现出了不同的物理力学性能。对于掺入钢纤维的,再生混凝土流动性降低、塌落度增大、保水性变差,但强度及抗折强度有所增加,劈裂抗拉强度无明显变化。对于掺入玻璃纤维的再生混凝土其流动性小幅增强、坍落度小幅减小、保水性基本不变,而抗压强度、抗折强度、劈裂抗拉强度均有一定的增强。对于掺入聚丙烯纤维的再生混凝土,其流动性增强,塌落度减小而抗压强度、抗折强度、劈裂抗拉强度均有一定的降低。对于上述结论可知,掺入玻璃纤维的再生混凝土相对来说性能更优越,建议选择该种混凝土进行推广。
The experimental study is based on the main mechanical properties of recycled concrete after C30 concrete incorporates different types of fibers at a coarse aggregate substitution rate of 50%. Choose to join the fiber with steel fiber, glass fiber, polypropylene fiber. Recycled Coarse Aggregates Choose concrete aged 40 years for abandoned buildings. 50% recycled concrete standard earth cube test blocks (150 mm × 150 mm × 150 mm), standard prismatic test blocks (150 mm × 150 mm × 300 mm) and size of 150 mm × 150 mm × 550 mm test block. Three test blocks are made for each size. During the preparation of the three test blocks, steel fibers, glass fibers and polypropylene fibers were respectively added to observe the fluidity, slump and water retention. Into the mold according to the concrete standard experimental conservation methods placed in conservation room curing 28 d after the test of its compressive strength, flexural strength, splitting tensile strength. A comparative analysis of the results obtained shows that recycled concrete with different fibers incorporates different physico-mechanical properties at the same coarse aggregate substitution rate. For the incorporation of steel fiber, recycled concrete reduced fluidity, slump increases, water retention deteriorated, but the strength and flexural strength increased, splitting tensile strength no significant change. For the recycled concrete with glass fiber incorporation, the fluidity slightly increased, the slump decreased slightly, the water retention was almost unchanged, and the compressive strength, flexural strength and splitting tensile strength all increased to some extent. For recycled concrete with polypropylene fiber, its fluidity is enhanced, the slump is reduced and the compressive strength, flexural strength and splitting tensile strength are all reduced. As can be seen from the above conclusions, the recycled concrete with glass fiber is relatively superior performance, it is recommended to choose the kind of concrete for promotion.