Study on Static and Fatigue Behavior of Reinforced Concrete Member with Low Quality Aggregate and its Effective Utilization

本研究选取了腐解花岗岩、熔融固化的城市生活垃圾混凝土用矿渣骨料和废旧屋面瓦片作为低质量骨料，研究了低质量骨料的新拌混凝土和硬化混凝土的性能。随后，对掺加上述骨料的混凝土制成的钢筋混凝土梁（RC梁）的静力、疲劳强度和变形特性进行了研究。新拌混凝土试验结果表明，分解花岗岩或废屋面瓦作为混凝土细骨料，要达到给定坍落度，需要掺加缓凝型引气型高效减水剂。低质量骨料混凝土的坍落度、随时间的空气损失、出血、凝结时间、抗压强度、干缩等基本性能与普通砂混凝土基本相同。除花岗岩碎裂外，低骨料混凝土的抗冻融性能比普通砂混凝土的抗冻融性能下降更多。第二部分研究了上述低质量骨料混凝土混凝土梁的强度和变形性能。钢筋混凝土梁采用的因素为配筋量、有无腹板加筋和加载方式（单向循环加载和在每个挠度幅值上重复3次的反向循环加载）。试验结果表明，采用JSCE规范中给出的观点，可以较准确地计算低骨料混凝土混凝土梁的抗弯承载力和抗剪承载力等强度。低骨料混凝土梁的裂缝宽度和挠度与普通砂混凝土梁的裂缝宽度和挠度几乎相同。第三项研究测试了普通混凝土和含有MSW（来自城市生活垃圾的熔融固化渣骨料）的RC梁的疲劳特性，并研究了将其用作混凝土粗骨料的可能性。试验结果表明：(1)与普通混凝土一样，普通混凝土的疲劳寿命分布符合对数正态分布；(2)普通混凝土的2X10^6次循环疲劳抗压强度比普通混凝土小4%。对于RC梁，(1)添加固体垃圾的RC梁在2X10^6次循环时的疲劳强度与添加普通混凝土的RC梁几乎相等，(2)添加固体垃圾的RC梁在重复荷载作用下的裂缝宽度或挠度的增加与添加普通混凝土的RC梁几乎相同。少

In this study, the decomposed granite, melt-solidified slag aggregate for concrete derived from municipal solid waste, and waste roof tiles were selected as a low quality aggregate and the properties of fresh and hardened concrete with low quality aggregate were investigated. Subsequently the properties of static and fatigue strength and deformation of reinforced concrete beams (RC beams) made of concrete with the mentioned above aggregate were also investigated.The test results of fresh concrete show that the dosage of a retardar type of air-entraining high-range water reducing agent required to attain the given slump when either the decomposed granite or the waste roof tiles are used as fine aggregate for concrete. The fundamental properties of concrete with a low quality aggregate such as slump and air loss with time, bleeding, setting time, compressive strength and drying shrinkage are almost the same as those of ordinary concrete with normal sand. However, the freeze-thaw resistan … More ce of concrete with low quality aggregate except for the decomposed granite drop away compared with that of concrete with normal sand.In second study, strength and deformation properties of RC beams made of concrete with mentioned above low quality aggregate were investigated. The factors adopted for reinforced concrete beams are amount of reinforcement, with or without web reinforcement and loading patterns (one is unidirectional cyclic loading and another is reversed cyclic loading with three load repetitions at each deflection amplitude). The test results show that the strength such as flexural capacity and shear capacity for the RC beam manufactured by concrete with low quality aggregate can be calculated with a considerable accuracy by the view given in JSCE's Specification. The crack width and deflection of RC beams with low quality aggregate are almost the same as those of ordinary RC beam with normal sand.Third study examined fatigue characteristics of the plain concrete and the RC beams with a MSW (Melt-solidified slag aggregate for concrete derived from municipal solid waste) and examined the possibility of its utilization as coarse aggregate for concrete. The test results show that (1) the distribution of fatigue life of both plain concrete and RC beam made of concrete with MSW was confirmed to the logarithmic normal distribution as well as ordinary concrete, (2) the fatigue compressive strength at 2X10^6 cycles for the plain concrete with MSW is smaller by 4 % than that of ordinary concrete. With RC beam, (1) the fatigue strength at 2X10^6 cycles for RC beam with MSW is almost is almost equal to that of RC beam with ordinary concrete, (2) the increase of crack width or deflection under repeated loading of RC beam with MSW is almost the same as those of ordinary concrete RC beam. Less