Carbonation of concrete is one of the most important factors for durabilityc of concrete structures. Although there are some formulae to predict the carbonation speed, quite few experimental studies have been reported concerning the influence of environmental moisture and temperature on the carbonation speed, so far. In this paper, a parametric study was performed to investigate the influence of environmental moisture and temperature on the carbonation speed of mortar. While accelerated carbonation tests were carried out, water cement ratio, relative humidity and temperature were changed. In the moisture condition of 40-50 % RH, the carbonation was mostly accelerated. The higher the temperature, the faster the speed of carbonation became. Temperature increased proportionally in the tested range from 15°C to 37.5°C. Finally carbonation speed of concrete was estimated all over Japan on the basis of the mean values of climate data (relative humidity and temperature) in each region reported by Japan Meteorological Agency.
