EXPOSURE TEST AND NUMERICAL SIMULATION ON THE INFLUENCE OF OUTDOOR WEATHER ACTION ON THE DRYING SHRINKAGE OF CONCRETE

Abstract

 This paper describes experiments and numerical simulations on the influence of weather actions such as temperature and humidity, precipitation, and solar radiation on the drying shrinkage of concrete. The test specimens casting at the same time were exposed at four outdoor locations in Japan and were measured the time-dependent change of water content and shrinkage strain. Experimental results showed that the shrinkage strain for one year was almost the same in each experimental location, but the progress of shrinkage in each season was different. By examination using the numerical simulation of moisture transfer and shrinkage strain of concrete that can consider the influence of temperature and humidity fluctuations, solar radiation, and precipitation, it was revealed that humidity fluctuations and rainfall had a great influence on the shrinkage behavior. A coefficient to consider the influence of humidity fluctuation and rainfall was calculated from the average humidity and the ratio of rainfall time, and the apparent relative humidity was calculated by multiplying the average humidity by the coefficient. It was shown that the shrinkage strain of concrete outdoors can be easily predicted by using JSCE shrinkage prediction formula which applied apparent relative humidity.