钢筋与活性粉末混凝土粘结性能的试验研究

发布时间：2018-04-29 03:41

本文选题：活性粉末混凝土 + 粘结应力-滑移本构模型　；参考：《北京交通大学》2013年博士论文

【摘要】：摘要：活性粉末混凝土是一种具有超高强度、高韧性、高耐久性、高环保性的新型水泥基复合材料,在土木工程领域具有广阔的应用前景。工程中活性粉末混凝土构件多以配筋的形式出现,为研究钢筋与活性粉末混凝土之间的协同作用机理,本文通过梁式试验、中心拔出试验、钢筋内贴片试验对变形钢筋与活性粉末混凝土之间的粘结性能进行了研究。分析了变形钢筋在活性粉末混凝土构件中的粘结锚固机理和粘结锚固强度变化规律,以解决活性粉末混凝土构件中钢筋的锚固设计问题,为活性粉末混凝土规范的编制提供依据。论文主要工作和结论如下： (1)进行了一批活性粉末混凝土梁式粘结试验,通过改变活性粉末混凝土内钢纤维体积掺量、保护层厚度、粘结长度等因素,分析了各因素对试件破坏形式、粘结应力-滑移曲线、粘结锚固特征值的影响。研究表明：锚固条件对钢筋与活性粉末混凝土之间的粘结性能具有很大影响并对试验结果进行统计回归,得出了变形钢筋与活性粉末混凝土之间的粘结锚固强度和滑移的计算公式； (2)通过梁式试验和中心拔出试验对钢纤维体积掺量为0.0%～2.0%的活性粉末混凝土与钢筋之间的粘结性能进行了研究,对比分析了不同试验方法下粘结强度随钢纤维体积掺量变化规律。同时进行了一组C40混凝土梁式试验,与钢纤维体积掺量为2.0%的活性粉末混凝土试件进行对比,研究变形钢筋在不同混凝土基体中粘结性能差异,并从微观结构方面分析了活性粉末混凝土的粘结锚固机理。研究表明：两种试验方法下得到的粘结强度都随钢纤维体积掺量的增加而增大,但梁式试验的粘结强度增长趋势大于中心拔出试验,钢纤维体积掺量为0.0%时,中心拔出试验的粘结强度大于梁式试验；钢纤维体积掺量为0.5%-2.0%时,中心拔出试验的粘结强度小于梁式试验；变形钢筋与活性粉末混凝土之间的粘结强度要远大于C40混凝土；活性粉末混凝土致密的结构及钢纤维的掺入是其具有超高粘结强度的原因； (3)进行了钢筋内贴片试验,根据实测钢筋应变,分析了不同位置处粘结应力变化规律,研究粘结长度内变形钢筋在活性粉末混凝土中的粘结应力分布规律,推导出了反映这种变化的位置函数；根据试验结果推导的粘结锚固特征值将粘结应力-滑移曲线分段,建立了考虑粘结位置的粘结应力-滑移本构模型； (4)在上述试验基础上,通过锚固可靠度分析及现有规范对钢纤维体积掺量为0.0%～2.0%的活性粉末混凝土中变形钢筋的粘结长度提出了实用设计建议,为制定相关规范提供了依据。
[Abstract]:Abstract: reactive powder concrete (RPC) is a kind of new cement matrix composite with super high strength, high toughness, high durability and high environmental protection. It has a broad application prospect in civil engineering field. In order to study the mechanism of synergistic action between rebar and reactive powder concrete, the beam test and central pull-out test are carried out in this paper. The bonding behavior between deformed steel bar and reactive powder concrete (RPC) was studied by internal patch test. The mechanism of bond anchoring of deformed steel bars in reactive powder concrete (RPC) members and the variation law of bond anchoring strength are analyzed in order to solve the problem of anchoring design of rebar in reactive powder concrete (RPC) members. To provide the basis for the preparation of reactive powder concrete code. The main work and conclusions are as follows: 1) A batch of beam-type bond tests of reactive powder concrete (RPC) were carried out. By changing the volume content of steel fiber, the thickness of protective layer and the bond length, the failure modes of the specimens were analyzed by changing the volume content of steel fibers, the thickness of the protective layer and the bond length of the RPC. The bond stress-slip curve and the effect of bond anchoring eigenvalue. The results show that the anchoring conditions have a great influence on the bond properties between rebar and reactive powder concrete (RPC) and the test results are statistically regressed. The formula of bond Anchorage strength and slip between deformed steel bar and reactive powder concrete is obtained. 2) through beam test and central pull-out test, the bond behavior between reactive powder concrete (RPC) with 2.0% steel fiber volume and steel fiber volume is studied, and the change of bond strength with steel fiber volume content under different test methods is compared and analyzed. At the same time, a group of C40 concrete beam tests were carried out, which were compared with the reactive powder concrete specimens containing 2.0% steel fiber volume. The difference of bond behavior of deformed steel bars in different concrete matrix was studied. The bonding and anchoring mechanism of reactive powder concrete is analyzed from microstructure. The results show that the bond strength of the two test methods increases with the increase of the volume content of steel fiber, but the increasing trend of bond strength of beam test is larger than that of central pull-out test, and when the volume content of steel fiber is 0.010, the bond strength of beam test is larger than that of central pull-out test. The bond strength of the central pull-out test is greater than that of the beam test, the bond strength of the central pull-out test is smaller than that of the beam test when the volume content of steel fiber is 0.5- 2.0%, the bond strength between the deformed steel bar and the reactive powder concrete is much higher than that of the C40 concrete. The dense structure of reactive powder concrete and the incorporation of steel fiber are the reasons for its super high bond strength. According to the measured strain of steel bar, the variation law of bond stress at different positions is analyzed, and the distribution of bond stress of deformed steel bar in reactive powder concrete (RPC) in bond length is studied. The position function reflecting this change is derived, and the bond stress-slip curve is segmented according to the eigenvalue of bond anchoring derived from the test results, and the bond stress-slip constitutive model considering the bond position is established. 4) on the basis of the above tests, through the Anchorage reliability analysis and the existing codes, the paper puts forward some practical design suggestions for the bond length of deformed steel bar in the reactive powder concrete (RPC) with the volume content of steel fiber as 0.00%, which provides the basis for the formulation of relevant codes.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU528

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