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

本研究以分解花岗岩、熔融固化城市生活垃圾混凝土矿渣集料和废弃屋面瓦为低质量集料，研究了低质量集料新拌混凝土和硬化混凝土的性能。在此基础上，研究了混凝土梁的静力、疲劳强度和变形性能。新拌混凝土的试验结果表明，无论是将分解的花岗岩用作混凝土的细集料，还是将废弃屋面瓦用作混凝土的细集料，缓凝型引气高效减水剂的用量都需要达到给定的坍落度。掺低质量骨料混凝土的坍落度、漏气量随时间变化、泌水、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。然而，抗冻融…与普通砂混凝土相比，除分解花岗岩外，掺低质量骨料的混凝土Ce均有较大幅度的下降。研究二，研究了上述低骨料混凝土的强度和变形性能。钢筋混凝土梁采用的因素包括配筋量、有无腹筋和加载方式(一种是单向循环加载，另一种是反复加载，每个挠度幅值重复加载三次)。试验结果表明，用低质量骨料混凝土制造的钢筋混凝土梁的抗弯、抗剪等强度均可按JSCE规范的观点进行计算，计算精度较高。劣质骨料混凝土梁的裂缝宽度和挠度与普通砂质钢筋混凝土梁的裂缝宽度和挠度基本相同。第三项研究考察了素混凝土和城市生活垃圾熔融矿渣混凝土梁的疲劳特性，并探讨了将其用作混凝土粗集料的可能性。试验结果表明：(1)掺垃圾素混凝土和普通混凝土的疲劳寿命均服从对数正态分布；(2)掺垃圾素混凝土的2×10~6周疲劳抗压强度比普通混凝土降低4%。对于钢筋混凝土梁，(1)掺城市生活垃圾的钢筋混凝土梁的2×106周疲劳强度与普通混凝土几乎相同；(2)在反复荷载作用下，掺垃圾的钢筋混凝土梁的裂缝宽度或挠度增量与普通混凝土钢筋混凝土梁基本相同。较少

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