大量实践理论分析表明,钢筋砼构件基本上都是带裂缝工作的,只是有些裂缝很细,甚至肉眼看不见(缝宽<0.5mm),一般对结构的使用无大的危害,允许其存在。但有些裂缝在使用荷载或外界物理及化学因素作用下,不断产生和发展引起砼碳化、保护层剥落及钢筋锈蚀,使钢筋砼强度和刚度受到削弱,耐久性降低,严重时甚至发生垮塌事故,危害结构的正常使用,必须加以防治。 A large number of practical theoretical analysis shows that the reinforced concrete components are basically working with cracks, but some cracks are very thin, or even the naked eye can not see (slit width <0.5mm), the general use of the structure without great harm, allowing its existence. However, some cracks under the action of load or the external physical and chemical factors, continue to produce and develop concrete carbonization, protective layer peeling and steel corrosion, the reinforced concrete strength and rigidity weakened, reduced durability, serious collapse occurred even in the event of collapse, Hazard structure of the normal use, must be controlled.