由ASR引起的箍筋断裂试验研究

发布时间：2018-04-20 03:01

本文选题：ASR + 实验　；参考：《扬州大学》2014年硕士论文

【摘要】：根据近年来的调查发现,日本的一些构造物中发生了碱骨料反应(ASR)而导致混凝土膨胀,实际构造物上产生了表面裂缝及整体变形；同时,膨胀导致的内部箍筋频繁的发生断裂现象。基于研究现状,构造物的角落处的张开变形可能会促使箍筋第一次弯曲产生的初期裂缝进一步发展,甚至导致箍筋的断裂。以前学者只是基于外部的角落的张开变形来推测内部钢筋变形情况,但是箍筋角落处的张开变形没有被直接证明。所以,找出外观劣化特点与内部箍筋破断的关系和直接证明内部膨胀导致箍筋变形是本实验研究的重点。为了模拟内部ASR膨胀引起的内部箍筋破断及约束混凝土的退化和破坏,将膨胀混凝土浇筑在中心空心、外围包裹的普通混凝土框架中,制作了6个试件进行了实验。参数设计为：从约束方面考虑,设置不同配筋率的箍筋和不同厚度的外围普通混凝土框架；从内部膨胀力考虑,设置不同的内部膨胀混凝土的量；从钢筋种类考虑,设置了3中箍筋来考察箍筋的损伤破断情况在实验过程中,测量了表面的裂缝和变形情况,以此来下推测内部箍筋的运动情况；此外,观察了不同箍筋的在第一次弯曲时产生的初始裂缝。同时,膨胀实验结束后,将箍筋取出,再次观察了由于内部膨胀使箍筋产生的进展裂缝。接着,作者将外观劣化进行详细了分类,总结了箍筋的运动。因此,进一步的分析的目的是研究外部变形的特征和原理,直接调查箍筋的运动情况。由于内部膨胀,根据引起裂缝和变形力的不同,作者把裂缝和变形情况进行研究分类,讨论了其产生的原因。最后,直接通过测量箍筋弯曲部位来确定膨胀前后的角度,通过结合外部劣化情况和箍筋变形情况来推测由内部ASR膨胀引起的箍筋断裂的机理。
[Abstract]:According to investigations in recent years, some structures in Japan have taken place alkaline aggregate reaction (ASR), resulting in concrete expansion, resulting in surface cracks and overall deformation in the actual structures; at the same time, The internal stirrups are frequently fractured due to expansion. Based on the present research situation the opening deformation at the corner of the structure may promote the further development of the initial cracks produced by the first bending of the stirrups and even lead to the fracture of the stirrups. In the past, scholars only speculated on the deformation of internal steel bar based on the opening deformation of the external corner, but the opening deformation at the corner of stirrups was not directly proved. Therefore, finding out the relationship between appearance deterioration and internal stirrups breaking and directly proving that internal expansion leads to stirrups deformation is the key point of this experiment. In order to simulate the fracture of internal stirrups and the degradation and failure of confined concrete caused by internal ASR expansion, six specimens were made by pouring expansive concrete into the hollow and outer concrete frame. The parameters are designed as follows: considering the constraints, setting stirrups with different reinforcement ratios and ordinary concrete frames with different thickness; considering the internal expansion force, setting different amount of internal expansive concrete; considering the types of reinforcement, Three stirrups are set up to investigate the damage and fracture of stirrups. During the experiment, the cracks and deformation of the surface are measured to infer the movement of the internal stirrups. The initial cracks in the first bending of different stirrups are observed. At the same time, after the expansion experiment, the stirrups are removed and the progressive cracks caused by internal expansion are observed again. Then, the author classifies the appearance deterioration in detail and summarizes the movement of stirrups. Therefore, the purpose of further analysis is to study the characteristics and principles of external deformation and investigate the movement of stirrups directly. Due to internal expansion, according to the difference of fracture and deformation force, the author classifies the fracture and deformation, and discusses the causes of the fracture and deformation. Finally, the angle before and after expansion is determined directly by measuring the bending position of stirrups, and the fracture mechanism of stirrups caused by internal ASR expansion is inferred by combining the external deterioration and the deformation of stirrups.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375

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