聚丙烯纤维再生混凝土梁受弯性能试验研究

发布时间：2018-11-19 15:35

【摘要】：使用再生混凝土粗骨料代替天然骨料制备混凝土,可以节约资源,降低污染,形成可循环利用的资源,对社会发展带来积极影响。但是再生混凝土因再生骨料的天然缺陷导致再生混凝土内部微裂纹、空隙较多,使混凝土抗压强度、抗拉强度等性能降低,制约了再生混凝土的广泛应用。在再生混凝土中加入聚丙烯纤维以研究聚丙烯纤维对再生混凝土梁受弯性能的影响。首先制备尺寸、配合比、再生骨料取代率及纤维掺量相同的普通混凝土、聚丙烯纤维混凝土、再生混凝土和聚丙烯纤维再生混凝土四个组别的标准立方体试块测试其28天抗压强度,结果表明聚丙烯纤维混凝土立方体试块抗压强度较普通混凝土增大3%,再生混凝土立方体试块抗压强度较普通混凝土降低9.7%,聚丙烯纤维再生混凝土立方体试块抗压强度较再生混凝土提高5.2%。对聚丙烯纤维再生混凝土破坏界面进行电镜扫描微观观测,可以看出聚丙烯纤维再生混凝土中再生骨料与砂浆粘结界面裂缝宽度与再生混凝土相比较小,砂浆中微裂纹与空隙数量较少,纤维与砂浆破坏状态为纤维拔出型破坏,纤维阻裂作用十分明显。制备参数与混凝土立方体标准试块相同的四个组别混凝土梁,对其受弯性能进行试验,对比分析它们开裂荷载、承载能力极限状态荷载、挠度变化、裂缝扩展状态,以检测聚丙烯纤维对再生混凝土梁受弯性能的影响。对四组别混凝土梁开裂荷载和极限荷载进行理论计算,探讨现行计算公式对聚丙烯纤维再生混凝土梁计算的可靠度。经试验结果分析得出再生混凝土梁开裂弯矩较普通混凝土梁降低8.2%,聚丙烯纤维混凝土梁开裂弯矩大于普通混凝土梁9.1%,聚丙烯纤维再生混凝土梁开裂弯矩较再生混凝土梁提高14.1%；达到承载能力极限状态时,再生混凝土梁最大裂缝宽度高于普通混凝土梁16.1%,高于聚丙烯纤维再生混凝土梁23.2%,纤维阻裂效用明显；弹塑性阶段相同荷载作用下掺入聚丙烯纤维混凝土梁挠度值较普通混凝土梁与再生混凝土梁整体刚度较好,最终破坏完全失去承载能力时,普通混凝土梁挠度值高于再生混凝土梁15%,聚丙烯纤维混凝土梁挠度值高于普通混凝土梁15.5%,聚丙烯纤维再生混凝土梁挠度值高于再生混凝土梁16%,掺入聚丙烯纤维后混凝土梁整体刚度与延性明显提高；四组试件达到承载能力极限状态时,再生混凝土承载力测量值小于普通混凝土梁6.9%,聚丙烯纤维混凝土梁承载力试验值高于普通混凝土梁4.5%,聚丙烯纤维混凝土梁承载力测量值高于再生混凝土梁4.5%,掺入聚丙烯纤维可以提高混凝土梁的承载能力极限状态承载力。最后应用ANSYS软件对混凝土梁受弯进行非线性数值模拟分析,进一步比对分析聚丙烯纤维对再生混凝土梁受弯性能的影响,模拟试验结果与实际试验结果较为接近,承载能力极限状态下,再生混凝土梁挠度值为6.351mm,,聚丙烯纤维再生混凝土梁挠度值为6.09mm；聚丙烯纤维再生混凝土梁模拟承载能力极限状态荷载值为144.53kN,较再生混凝土梁荷载模拟值增大3.2%。
[Abstract]:The recycled concrete coarse aggregate is used to replace natural aggregate to prepare concrete, which can save resources, reduce pollution, and form recyclable resources and have positive influence on social development. However, the natural defects of the recycled concrete lead to the micro-cracks in the recycled concrete, the void is more, the compressive strength and the tensile strength of the concrete are reduced, and the wide application of the recycled concrete is restricted. Polypropylene fiber was added to the recycled concrete to study the effect of the polypropylene fiber on the flexural properties of the regenerated concrete beam. The normal concrete, the polypropylene fiber concrete, the recycled concrete and the polypropylene fiber regenerated concrete are prepared by first preparing the normal concrete, the polypropylene fiber concrete, the recycled concrete and the polypropylene fiber regenerated concrete, The results show that the compressive strength of the test block of the polypropylene fiber concrete cube is 3% higher than that of the common concrete, the compressive strength of the recycled concrete cube is less than that of the ordinary concrete by 9. 7%, and the compressive strength of the test block of the polypropylene fiber is higher than that of the recycled concrete. It can be seen that the crack width of the recycled aggregate and the mortar bonding interface in the recycled concrete of the polypropylene fiber is less than that of the recycled concrete, and the micro-cracks and the number of voids in the mortar can be seen. the damage state of the fiber and the mortar is less, the fiber resistance cracking effect is very good, It is obvious that the preparation parameters are the same as that of the concrete cube standard test block, and the bending performance of the concrete beams is tested, and the cracking load, the bearing capacity limit state load, the deflection change and the crack are compared and analyzed. Joint expansion state to detect the bending of the recycled concrete beam by the polypropylene fiber The effect of the performance on the cracking load and ultimate load of the four-group concrete beam is calculated, and the current calculation formula is discussed in this paper. The results of the test show that the crack bending moment of the regenerated concrete beam is lower than that of the ordinary concrete beam by 8.2%, the cracking moment of the polypropylene fiber concrete beam is larger than that of the ordinary concrete beam, and the cracking moment of the polypropylene fiber reinforced concrete beam is higher than that of the regenerated concrete beam. 14. 1%; when the limit state of the bearing capacity is reached, the maximum crack width of the recycled concrete beam is higher than that of the ordinary concrete beam (16.1%), which is higher than that of the polypropylene fiber regenerated concrete beam (22.3%), and the fiber resistance The crack effect is obvious; the deflection value of the concrete beam of the polypropylene fiber is better than that of the ordinary concrete beam and the regenerated concrete beam under the same loading action in the elastic-plastic phase, and the deflection value of the common concrete beam is higher than that of the regenerative concrete beam when the ultimate failure completely loses the bearing capacity. The deflection value of the concrete beam of the polypropylene fiber is higher than that of the ordinary concrete beam by 15%, the deflection value of the polypropylene fiber reinforced concrete beam is higher than that of the recycled concrete beam, and the overall rigidity and the ductility of the concrete beam after the incorporation of the polypropylene fiber are obviously improved; and the four groups of test pieces reach the bearing capacity. In the limit state, the measured value of the bearing capacity of the recycled concrete is less than 60.9% of the common concrete beam, the test value of the bearing capacity of the polypropylene fiber concrete beam is higher than that of the common concrete beam, and the measured value of the bearing capacity of the polypropylene fiber concrete beam is higher than that of the recycled concrete. The load capacity limit of the concrete beam can be improved by the incorporation of the polypropylene fiber in 4.5% of the beam The state-carrying capacity of the concrete beam is simulated by using the ANSYS software, and the influence of the polypropylene fiber on the bending performance of the regenerated concrete beam is further compared, and the simulation test result is close to the actual test result, and the bearing capacity In the capacity limit state, the deflection value of the regenerated concrete beam is 6.351mm, and the deflection value of the regenerated concrete beam of the polypropylene fiber is 6.09mm; the ultimate state load value of the simulated bearing capacity of the polypropylene fiber regenerated concrete beam is 144.53kN, and the load die of the regenerated concrete beam
【学位授予单位】：延边大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU377

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