Modeling capillary water absorption behavior of concrete with carbonated surface layers

Abstract

This paper analyzed the water absorption behavior in concrete with carbonated surface layers. First, the capillary absorption model for surface carbonated concrete was proposed based on surface carbonated pore size variation characteristics. Capillary absorption tests were then designed and conducted to validate the proposed water absorption model. Based on the proposed absorption model, parametric studies were conducted. Both experimental and simulation results indicate that carbonation leads to a reduction in pore size in concrete, with a decrease in radius of approximately 2–4 nm. Parametric studies show that the progress of capillary absorption depends heavily on the thickness of surface carbonation layer. Moreover, for the same thickness of carbonation layer, w/c ratio within the range between 0.30 and 0.60 poses negligible influences on the capillary absorption process. Therefore, it is the main parameter that needs to be determined for the evaluation of water absorption in long-term service of concrete.