Shrinkage effect on cracking resistance of flexural reinforced concrete members

Abstract

A time-dependent stress-strain state of reinforced concrete elements induced by gradually developing shrink-age of concrete is analysed. Depending on environmental conditions the early age concrete shrinkage can produce a significant tensile stress in concrete that reduces the crack-ing resistance of the cross-section. To analyse this phenom-enon a numerical model is proposed. For the exact analytical prediction of the time-dependent stress-strain state induced by the restrained shrinkage, the key parameter is the coeffi-cient of aging which is strongly dependent on the time-evo-lution of tensile stress of concrete and modulus of elasticity. The values of this coefficient obtained in the current analy-sis are suitable for the proper evaluation of the reduction of cracking resistance of the cross-section induced by re-strained shrinkage evolving during concrete hardening pro-cess in a period prior to element loading.