This paper introduces the reinforced concrete crack types and causes, from material factor, design factors and external factors three aspects discusses the specific methods of preventing the crack.
It was indicated that the linear defect appeared after machining is not crack, it is the appearance of oxide film involved in the casting under the effect of external force.
结果表明，这种加工后出现的线性缺陷并非裂纹，而是卷入铸件的氧化膜受外力作用后在叶片表面的显现。
3
Through observing on the building external coating in Beijing, it was found that the inferiority of the coating are crack, falling, fading and stain.