Among the shrinkage types of concrete, plastic shrinkage and dry shrinkage are the main causes of volume deformation of concrete. When cement contacts with water, the crack of concrete bridge is a common technical problem, and the crack of concrete bridge is a common technical problem. The sub-micro research is carried out through modern concrete strength theory. Rich engineering practice experience.

　　結果表明，混凝土結構的裂縫是不可避免的，細裂縫的使用是無害的。在混凝土橋梁的設計計算理論中，允許構件開裂，但裂縫寬度不能控制得太寬。還有一種方法可以修復和加強混凝土橋梁的裂縫。找出裂紋的真正原因后，采用正確合理的修復材料和方法。

　　The results show that cracks in concrete structures are inevitable and the use of fine cracks is harmless. In the design and calculation theory of concrete bridges, cracks are allowed, but the width of cracks can not be controlled too wide. There is another way to repair and strengthen cracks in concrete bridges. After finding out the real cause of the crack, the correct and reasonable repair materials and methods are adopted.

　　加強橋梁構件，提高結構性能，提高橋梁承載能力，延長橋梁使用壽命，適應現代交通運輸的要求。可以看出，設計裂縫、施工質量差、監理質量差等因素都可能導致混凝土橋梁產生裂縫。因此，嚴格按照有關標準和技術標準進行設計、施工和監理是保證結構和耐久性的前提和基礎。

　　Strengthen the bridge components, improve the structural performance, improve the bearing capacity of the bridge, extend the service life of the bridge, and adapt to the requirements of modern transportation. It can be seen that design cracks, poor construction quality, poor supervision quality and other factors may lead to cracks in concrete bridges. Therefore, design, construction and supervision in strict accordance with the relevant national standards and technical standards are the premise and foundation to ensure the safety and durability of structures.

　　在經營管理過程中，進一步加強檢查管理，及時發現和處理問題也是非常重要的環節。鋼筋銹蝕引起的裂紋。由于混凝土質量差或保護層厚度不足，混凝土保護層被二氧化碳碳化到鋼表面，降低了鋼筋周圍混凝土的堿度。或者由于氯離子的介入，鋼筋周圍氯離子的含量較高，導致鋼筋表面氧化膜斷裂，鋼筋內鐵離子侵入凝固。土壤中的氧氣與水發生反應而生銹。

　　In the process of operation and management, it is also very important to further strengthen inspection and management, and to find and deal with problems in time. Cracks caused by corrosion of steel bars. Due to the poor quality of concrete or insufficient thickness of protective layer, the protective layer of concrete is carbonized by carbon dioxide to the steel surface, which reduces the alkalinity of concrete around steel bars. Or because of the intervention of chloride ion, the chloride ion content around the reinforcing bar is high, which leads to the rupture of the oxide film on the surface of the reinforcing bar and the invasion and solidification of iron ion in the reinforcing bar. Oxygen in the soil reacts with water and rusts.