城市井盖周边混凝土破坏原因分析及修复的研究

发布时间：2018-03-23 11:40

本文选题：检查井　切入点：调平层　出处：《武汉理工大学》2015年硕士论文

【摘要】：一座城市的健康发展,少不了检查井的重要作用,检查井结构包括井体基础、井室、井筒、调平层、井圈、井盖,但是在实际生活中,我们经常可以看到车行道各类检查井周边混凝土的破坏现象。本文通过实地调查以及查阅相关文献,认为检查井周边混凝土主要有两方面原因,其一由于检查井下部的调平层会受到反复的拉应力和剪切力作用,薄弱的调平层首先出现破坏并出现沉降差,让井体受到更大的冲击力,加剧检查井的破坏,另外井圈混凝土在车辆载荷作用下,也会受到反复的剪切力,产生疲劳破坏,其受到车辆载荷应力和内外温度差形成的温度应力也会加速井圈混凝土的破坏。针对上述混凝土破坏原因并结合检查井的结构特点,作者认为调平层和井圈应分别采用细石钢纤维混凝土、聚丙烯纤维混凝土,并通过试验研究配制了新修检查井周边混凝土即调平层和井圈混凝土材料,和已经破坏的检查井周边混凝土的修补材料。本文在实验室对调平层混凝土、井圈混凝土的材料组成、配合比及混凝土性能进行了系统研究,并借助XRD、SEM对修补材料的水化机理进行了分析、采用界面显微硬度值对新老混凝土粘结性能规律进行验证分析,研究表明:(1)在新修检查井调平层混凝土中,当混凝土中钢纤维体积掺量为1%时,28d抗折强度为13.73MPa,抗压强度59.6MPa,劈拉强度为5.53MPa。(2)在新修检查井井圈混凝土中,聚丙烯纤维体积掺量在0.10%时,28d抗折强度为9.03MPa,抗压强度53.6MPa,劈拉强度为4.06MPa,且耐磨度达到2.87千转1/2/mm。(3)对于已破坏的检查井的调平层混凝土修补材料中,在硫铝酸盐水泥掺量为15%时1d力学强度达到最高值,掺入5%的偏高岭土后,对28d强度增长较明显,掺入1%的钢纤维后,显著增加了修补材料的韧性,1d抗折、抗压强度分别达到8.98MPa、38.8MPa,完全能满足1d通车标准。(4)结合XRD和SEM微观测试手段分析修补材料对应的净浆的水化产物与结构得知,硫铝酸盐水泥的掺入能促进早期水化,但后期水化程度不足,偏高岭土的掺入可以促进二次水化反应,使28d净浆水化结构更加致密。(5)调平层修补材料中掺入5%的偏高岭土后,28d粘结强度提高17.2%;修补材料中加入体积掺量为1%钢纤维,1d粘结拉拔强度1.42MPa,28d达到2.35MPa,能满足1d通车标准。(6)在已破坏的检查井的井圈混凝土修补材料中,体系中掺入体积掺量为0.1%的聚丙烯纤维,1d井圈修补材料抗压、抗折强度分别达到35.5MPa、6.32MPa,能满足1d通车标准,聚丙烯纤维亦能改善混凝土粘结性能,其中聚丙烯纤维的最佳掺量为0.1%,1d粘结拉拔强度达到1.26MPa,28d达到2.02MPa,均能满足1d通车标准。
[Abstract]:The healthy development of a city is not without the important role of inspection wells, which include well body foundation, well chamber, wellbore, leveling zone, well ring, well cover, but in real life, We can often see the damage phenomenon of concrete around various inspection wells in the vehicular roadway. Through field investigation and reference of relevant documents, this paper thinks that there are two main reasons for the concrete around the inspection well. For one thing, the flattening layer at the bottom of the inspection well will be subjected to repeated tensile stress and shear force, and the weak leveling zone will first be destroyed and there will be settlement difference, which will make the well body suffer greater impact force and aggravate the damage of the inspection well. In addition, under the action of vehicle load, the well ring concrete will also be subjected to repeated shear stress, resulting in fatigue damage. The thermal stress caused by vehicle load stress and temperature difference between inside and outside will also accelerate the destruction of well ring concrete. In view of the above reasons of concrete failure and combined with the structural characteristics of the inspection well, The author thinks that the fine stone steel fiber concrete and polypropylene fiber concrete should be used in the leveling layer and the well ring respectively, and through the experimental study, the concrete around the new workover inspection well is made up, that is, the leveling layer and the well ring concrete material. In this paper, the material composition, mix ratio and concrete performance of leveling layer concrete and well ring concrete are systematically studied in laboratory. The hydration mechanism of the repair material is analyzed by means of XRDX SEM, and the bonding behavior of the new and old concrete is verified and analyzed by using the microhardness value of the interface. The results show that: 1) in the leveling layer concrete of the new inspection well, When the volume content of steel fiber in concrete is 1, the flexural strength is 13.73MPa, the compressive strength is 59.6MPa, and the splitting tensile strength is 5.53MPa.-2) in the concrete of the newly repaired inspection well, the bending strength is 13.73MPa, the compressive strength is 59.6MPa, and the splitting tensile strength is 5.53MPa.f. When the volume content of polypropylene fiber is 0.10, the flexural strength is 9.03 MPa, the compressive strength is 53.6 MPa, the splitting tensile strength is 4.06 MPA, and the wear resistance is 2.87 krpm / 2 / mm. When the content of sulphoaluminate cement is 15, the mechanical strength reaches the highest value at 1 day, and after adding 5% metakaolin, the strength increases obviously for 28 days, and when 1% steel fiber is added, the toughness of the repair material is increased significantly for one day, and the flexural strength of the mending material is obviously increased after the addition of 5% metakaolin. The compressive strength reached 8.98 MPA / 38.8MPa respectively, which fully met the 1d opening standard. (4) the hydration products and structures of the paste corresponding to the repair materials were analyzed by XRD and SEM microcosmic test methods. It was found that the incorporation of sulphoaluminate cement could promote the early hydration. However, the degree of hydration was insufficient in the later stage, and the incorporation of metakaolin could promote the secondary hydration reaction. The bonding strength was increased by 17.2% after the addition of 5% metakaolin into the leveling layer repair material, and the bond drawing strength of 1% steel fiber was increased by adding 1% steel fiber into the repair material in 28 days, and the bond drawing strength reached 2.35 MPa in 28 days, which can meet the requirement of 1 d pass. In the corrugated concrete repair material of damaged inspection wells, The polypropylene fiber with 0.1% volume added in the system can be used to repair the annulus under compressive pressure, and the flexural strength is up to 35.5MPa and 6.32MPa respectively, which can meet the standard of opening to traffic for one day, and the polypropylene fiber can also improve the bond property of concrete. The optimum content of polypropylene fiber is 0.1 g / d bonding and drawing strength is 1.26 MPA / 28d and 2.02MPa / d, which can meet the standard of opening to traffic for 1d.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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