基于性能的活性粉末混凝土井盖应用研究

发布时间：2018-09-13 11:15

【摘要】：活性粉末混凝土(Reactive Powder Concrete,简称RPC)是一种抗压强度高且韧性、耐久性和体积稳定性良好的水泥基复合材料,将其运用在市政工程的井盖,能大大减轻结构自重和延长使用寿命。然而,目前对RPC井盖的相关研究较少,尤其在RPC井盖制作、脱模和开启等工艺,影响性价比的井盖厚度、钢纤维掺量选择等方面均缺乏深入的研究。为使RPC井盖能尽快应用于市政工程,本文开展了以下的研究工作：(1)进行了RPC井盖制备工艺的试验研究,形成一套较为系统的井盖制备技术,并对RPC井盖脱模与开启工艺进行了试验研究。结果表明,以往的钢纤维混凝土井盖脱模工艺不适用于RPC井盖,RPC井盖肋要有一定的倾斜度与倒角且包边与模具边缘要有间隙；RPC井盖采用细部构造成60°夹角的撬起装置的开启效率较高。(2)进行了不同结构形式的RPC井盖承载能力试验研究。结果表明,无论是极限承载力,还是在结构刚度、延性性能等方面,井字肋井盖均优于十字肋井盖,且井字肋井盖可以满足《钢纤维混凝土检查井盖》B级井盖的相关要求,可应用于公路或城市行车道上。(3)进行了14个RPC井字肋井盖的试验研究,试验参数为井盖厚度与钢纤维掺量。结果表明,40mm厚与45mm厚的RPC井盖承载能力相差不大,因此建议采用更轻更薄的40mm厚RPC井盖；钢纤维掺量3%、40mm厚的RPC井盖承载能力符合《钢纤维混凝土检查井盖》标准B级井盖的要求。(4)开展了RPC井盖、钢纤维混凝土井盖和铸铁井盖的经济效益分析,结果表明,在力学性能指标满足《钢纤维混凝土检查井盖》标准B级井盖要求的前提下,RPC井盖的材料价格略高于钢纤维混凝土井盖,但远远低于铸铁井盖,具有工程应用价值。(5)进行了RPC井盖的现场使用性能研究。结果显示,RPC井盖位于重级交通等级路段,经过车流量换算,RPC井盖若能经受住700万次左右标准轴重的冲击,将具有20年左右的疲劳使用寿命；使用过程中RPC井盖与井座吻合良好,产生噪音和跳动概率较铸铁井盖小,具有更为优越的使用性能；RPC井盖在使用过程中产生了裂缝,其原因可能为RPC井盖细部构造(如保护层厚度)不甚合理所致,将通过对上述构造的改进,以期获得耐久性能更好的RPC井盖。
[Abstract]:Reactive powder concrete (Reactive Powder Concrete,) is a kind of cement matrix composite with high compressive strength, toughness, durability and volume stability. Applying it to the manhole cover of municipal engineering can greatly reduce the structural weight and prolong the service life. However, there are few researches on RPC manhole cover at present, especially in the manufacturing, demoulding and opening processes of RPC well cover, the thickness of manhole cover which affects the performance to price ratio, and the selection of steel fiber content, etc. In order to make RPC well cover be applied to municipal engineering as soon as possible, the following research work has been carried out in this paper: (1) the experimental research on the preparation technology of RPC well cover has been carried out, and a set of systematic well cover preparation technology has been formed. The RPC well cover demoulding and opening process are also studied. The results show that the former steel fiber reinforced concrete manhole cover demoulding process is not suitable for RPC manhole cover ribbed with a certain inclination and chamfering, and there should be a gap between the edge and the die edge. The opening efficiency of the prying device with 60 掳angle is higher for RPC manhole cover. (2) the load-carrying capacity of RPC manhole cover with different structure is studied experimentally. The results show that, in terms of ultimate bearing capacity, structural stiffness and ductility, the well ribbed manhole cover is superior to the cross ribbed manhole cover, and the well ribbed manhole cover can meet the relevant requirements of steel fiber concrete check manhole cover > class B well cover. It can be applied to highway or urban carriageway. (3) the experimental study of 14 RPC well ribbed manhole covers is carried out. The experimental parameters are the thickness of well cover and the content of steel fiber. The results show that the bearing capacity of RPC well cover with 40 mm thickness is not much different from that of RPC well cover with 45mm thickness. Therefore, a lighter and thinner 40mm thick RPC well cover is recommended. The bearing capacity of RPC well cover with steel fiber content of 3mm and 40mm thickness meets the requirement of standard B class well cover. (4) the economic benefit analysis of RPC well cover, steel fiber concrete well cover and cast iron well cover is carried out, and the results show that, The material price of RPC manhole cover is slightly higher than that of steel fiber concrete manhole cover, but far lower than cast iron manhole cover. It has engineering application value. (5) the field performance of RPC well cover is studied. The results show that the RPC well cover is located in the heavy traffic grade section. If it can withstand the impact of about 7 million standard axle loads, the RPC well cover will have a fatigue life of about 20 years, and the RPC well cover and the well seat are in good agreement with each other in the process of operation. The noise and runout probability is smaller than that of cast iron manhole cover, and it has more superior performance. RPC manhole cover produces fracture in the process of use, which may be caused by the unreasonable structure (such as thickness of protective layer) of RPC manhole cover. Improvements will be made to the above structure in order to achieve better durability of RPC manhole covers.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU990.3

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