An analytical investigation of bond deterioration between rebar and ASR/DEF-damaged concrete with and without stirrup confinement using 3D RBSM
An analytical investigation of bond deterioration between rebar and ASR/DEF-damaged concrete with and without stirrup confinement using 3D RBSM
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DOI：
10.1016/j.conbuildmat.2022.128923
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发表时间：
2022-10
影响因子：
7.4
通讯作者：
Jie Luo;S. Asamoto;K. Nagai
中科院分区：
文献类型：
--
作者：
Jie Luo;S. Asamoto;K. Nagai
钢筋与混凝土之间的粘结性能对钢筋混凝土结构的安全至关重要。有必要研究由于碱-硅酸反应(ASR)和延迟钙矾石形成(DEF)破坏而影响实际结构的键劣化。本文采用三维刚体弹簧模型(3D RBSM)数值模拟方法，定量研究了箍筋约束条件下ASR/DEF轻微到严重损伤对混凝土与钢筋间拔出性能的影响。通过模拟发现，ASR损伤情况下的粘结应力在ASR拔出前的膨胀较小时增大，然后随着损伤程度的增加而减小，而DEF损伤情况下的粘结应力从一开始就一直在下降。此外，当损伤严重时，较高的箍筋约束有效地缓解了ASR和DEF损伤情况下的粘结劣化。更重要的是，可视化了扩展阶段和拔出阶段的应力发展和裂纹扩展。界面开裂条件因损伤类型(ASR或DEF)和箍筋约束程度的不同而不同，这是由于不同的开裂机理造成的。然而，反映ASR和DEF损伤整体损伤程度的混凝土裂缝数量增加的趋势是相似的，导致粘结应力也有类似的下降趋势。
The bond performance between rebar and concrete is essential for the safety of RC structures. There is a need for research on bond deterioration due to the alkali-silica reaction (ASR) and delayed ettringite formation (DEF) damage which affects real structures. In this paper, a parametric study is conducted to quantitatively study the effect of slight-to-severe ASR/DEF damage in the presence of stirrup confinement on the pullout behavior between concrete and reinforcement using three-dimensional rigid body spring model (3D RBSM) simulation. It is found through the simulation that the bond stress in ASR damaged cases increases when ASR expansion before pullout is small and then decreases as the damage level rises, while the bond stress in DEF damaged cases keeps decreasing from the beginning. Besides, higher stirrup confinement effectively mitigates bond deterioration in both ASR and DEF damaged cases when damage is serious. More importantly, stress development and crack propagation during the expansion stage and the pullout stage are visualized. Interface cracking condition varies according to the damage type (ASR or DEF) and the level of stirrup confinement due to different cracking mechanisms. However, the tendency for the number of cracks in the concrete to increase, which reflects the overall damage level in ASR and DEF damaged cases, is similar, resulting in a similar trend for bond stress to decrease.