2011 Volume 65 Issue 1 Pages 376-383
Penetration of the deterioration substances like water and chloride ions through cracks into the concrete, generally, induces and accelerates corrosion of reinforcing steel in reinforced concrete（RC）structures. The behavior of RC beams under sustained load is investigated to simulate RC structures in very severe chloride environment. As examination parameters, reinforcement stress with three levels of stress and cover of three different thicknesses are adopted. According to the results, the corrosion initiation time was not influenced by the reinforcement stress level as well as the cover thickness in cracked zone of beams under sustained loading, which as expected, was dependent on the cover thickness for beams without loading. Results also showed that the corrosion crack width became larger as the reinforcement stress became higher as well as the cover thickness became smaller. The time dependent deflection was calculated by using the effective flexural stiffness evaluated, in which the reduction of stiffness due to flexural craking, the influence of creep, and shrinkage with gradient in cross section, were considered. By comparisons between measured and calculated value, It was found that the effect of corrosion on long-term deflection can be observed for the beams with severely increasing of corrosion crack width；while such effect was not found for the beams whose corrosion crack width was less than 1mm.
