混凝土硬化后有抗压强度与耐久性良好的特性。但混凝土也存在着抗拉强度低;受拉时变形能力小,容易开裂等现象。如温度变化、收缩、膨胀、不均匀沉陷等原因引起的裂缝;有外载作用引起的裂缝;有养护环境不当和化学作用引起的裂缝等等。在实际工程中要认真对待解决问题。 Concrete hardened after a good compressive strength and durability characteristics. But there is also a tensile strength of concrete is low; when deformed by tension, small, easy to crack and so on. Such as temperature changes, shrinkage, expansion, uneven subsidence and other causes of cracks; there is a load caused by the cracks; have improper conservation and chemical reactions caused by the cracks and so on. In the actual project should be taken seriously to solve the problem.