Tensile Stresses Due to Reinforcement Restraining Shrinkage in Reinforced Concrete Slabs

摘要

Tensile stresses due to steel reinforcement restraining concrete shrinkage in effectively uncracked reinforced concrete slabs were studied. Numerical (computer) models were used to simulate the behavior of slab elements under a wide range of conditions. The results indicate that long-term values of the tensile stresses typically reach about 2 MPa. The ratio of the tensile stress to tensile strength increases over a long period of time, and it typically reaches a value of about 30%. The tensile stresses and the ratios of tensile stress to tensile strength depend mainly on the relative humidity of the slab environment, and the quantity and distribution of steel reinforcement. The tensile stresses are significant with regard to the effect they could have on the cracking (and stiffness) of reinforced concrete slabs. Furthermore, compression steel could be used to control the tensile stresses, in order to prevent cracking associated with shrinkage curvature.