Study On The Temperature Contraction Crack Control In Reinforced Concrete Cast-in-place Floor Slabs

Temperature contraction cracks on reinforced concrete cast-in-place floor slabs are harmful to structure's integrity and durability. In order to ensure buildings safe and used properly, crevices must be avoided and temperature should be controlled by plan in construction.According to cracks in reinforced concrete cast-in-place floor slabs, this paper carries out analyses as follow.1.Through analyzing their cause mechanism and influences such as contraction and creep deformation of concrete,steel bars in concrete, concrete components and construction factors, some technical measures are put forward.2.In the light of basic principle on conduction of heat, boundary conditions of practical engineering and all kinds of temperature cracks influences being taken into account, a new math model is made to have a calculation of the temperature stress in concrete. Through theoretical analysis, calculation formulas of concrete temperature stress and permitted pouring length are proposed.3.Crack control methods put into effect in practical engineering work perfectly, which verify their practical feasibility consequently.4.Practical engineering being taken as calculation example, numerical solutions of creep-temperature stress and concrete pouring length are obtained. By comparing these results with the numerical range permitted, the conclusion can be drawn that the technologies of crack holding adopted in this construction are possible in theory. For convenience of calculation, a program is edited and verified by practical engineering example.