【作者】 叶强；

【导师】 吴瑾；

【作者基本信息】 南京航空航天大学 ， 结构工程， 2008， 硕士

【摘要】 再生混凝土的应用为建筑垃圾回收利用提供了一个新的途径,是保持建筑业可持续发展的重要举措之一。再生混凝土的研究已经有50年的历史,事实上,没有研究结果表明再生骨料混凝土不能在建筑结构应用,只有少数耐久性方面的研究结果表明,再生骨料混凝土更适合于道路路基铺筑。再生骨料混凝土要应用于结构中,骨料的质量是至关重要的,主要原因是再生骨料表面包裹着一层多孔的砂浆。目前,已有不少关于再生混凝土构件方面的研究,但是,要搞清楚其结构性能以建立设计规范,目前的研究还是远远不够的,特别是国内外关于再生粗骨料钢筋混凝土梁弯曲刚度的研究更是少见。本文比较再生粗骨料混凝土梁和普通混凝土梁的抗弯性能,探讨再生骨料在构件中使用性能。通过再生混凝土强度指标试验,研究了再生混凝土棱柱体强度、弹性模量与立方体抗压强度关系。对27根再生混凝土梁和3根普通混凝土梁进行了正截面弯曲性能试验,研究了纵向受拉钢筋配筋率及混凝土抗压强度对正截面受力性能的影响、正常使用荷载作用下梁跨中挠度以及刚度的计算方法。本文主要工作及结论如下:1.相对于普通混凝土,再生骨料混凝土的弹性模量平均降低20%左右。2.相同荷载下,与普通混凝土梁相比,再生混凝土梁的受拉钢筋应变和受压区混凝土应变较大。3.使用规范公式计算再生混凝土梁正截面抗弯承载能力与实测值吻合较好。4.相同条件下,再生混凝土梁跨中挠度比普通混凝土梁跨中挠度大,约为11%。5.回归了再生混凝土梁在正常使用荷载作用下的短期刚度计算公式,再生混凝土梁受弯刚度相对于普通混凝土降低了10%左右,并借鉴国内外其他研究者相关数据对本文刚度公式进行了验证,结果吻合较好。更多还原

【Abstract】 The use of recycled aggregate concrete brings forward a new approach for the reuse of the building waste materials. This could be an important breakthrough for our endeavor towards sustainable development. The studies on the use of recycled aggregates concrete have been going on for 50 years. In fact, none of the results show that recycled aggregate concrete is unsuitable for structure. Only having inadequate number of studies in durability aspects, made recycled aggregate concrete to be preferred just as stuffing material for road construction. In utilizing recycled aggregate concrete in structural aggregate, the inferiority in concrete quality is a major concern. The main reason is that recycled aggregate contains significant amount of porosity in clinging mortar. In recent year, some studies concerning concrete and reinforced concrete made of recycled aggregate have been performed. However, those are not sufficient for making clear behavior of structural members leading to establishing design method. Especially, few studies concerning flexural stiffness of reinforced concrete beams with recycled coarse aggregate were performed.The aim of this contribution is to investigate the applicability of recycled aggregate containing high amount of cement paste as a structural aggregate by comparing the flexural properties of reinforced concrete members produced from recycled aggregate concrete with those of reinforced concrete members with ordinary concrete. Based on the test of cubes and prisms, the relationship between cubic compressive strength, prism strength and Young’s modules of recycled concrete are investigated. Flexural properties of 27 reinforced recycled concrete beams and 3 reinforced concrete beams are investigated experimentally. The major factors are compressive strength of recycled aggregate concrete and ratio of tension reinforcement. Flexural properties of reinforced recycled concrete beams, i.e. mid-span deflection under serviceable load and stiffness are discussed. The main conclusions are as following:1. Compared with ordinary aggregate concrete, the elastic modulus of recycled aggregate concrete is smaller by 20%.2. Under the same loadings, the strain of tensile steel and the strain of concrete in compression zone of recycled aggregate concrete beams are larger than that of natural aggregate concrete beams.3. The calculating method on bearing capability for natural aggregate concrete beam can satisfy the requirement of recycled aggregate concrete beams.4. The mid-span deflection of recycled coarse aggregate concrete beam was slightly larger than that of ordinary aggregate concrete beam by 11% under the same conditions.5. The calculating method on flexural stiffness of reinforced concrete beams with recycled coarse aggregate under service loading was obtained. The calculated values of mid-span deflection of recycled coarse aggregate beams are in good agreement with the test values and recycled coarse aggregate beam can satisfy the requirement under service loadings.更多还原