The strength of unsaturated polyester resin concrete was analyzed in specimens that had spent several decades in soil outdoors and specimens subjected to hydrothermal acceleration tests. The strength reduction of both specimens was proportional to the square root of elapsed time and similar to water absorption followed Fickʼs diffusion law. In addition, the specimens regained their strength after drying. These results suggest that the main mechanism of strength reduction of resin concrete is breaking of hydrogen bonds between the resin and aggregate by water molecules, not hydrolysis of polyester resin, which is the commonly accepted theory. Furthermore, the strength of the resin concrete that had spent time in soil outdoors could be estimated using a water absorption simulation of resin concrete.

This study has developed a methodology that incorporates the high-resolution weather model with the detailed airborne seasalt transport model in order to obtain high-resolution corrosive environment map. In the developed method, the multiscale weather model named MSSG computes the sea salt transportion, without considering the seasalt generation processes, under the side-boundary conditions for seasalt concentration profiles provided by the detailed seasalt generation and transport model named NuWiCC-ST. That is, the two models are coupled offline through the seasalt concentration data. The developed method has been applied for obtaining a 100 m-resolution monthly average corrosive environment map for Choshi city focusing on the Choshi bridge. The seasalt fluxes observed by the dry-gauze method have been compared with the present numerical results and confirmed the reliability of the present method.

The atmosphere corrosion tendency across a factory site in a littoral industrial complex was investigated using the carbon steel adhesive-backed test coupons. 150 test coupons of carbon steel were placed in the researched factory site and exposed to the atmosphere for a year. There was a tendency that the corrosion rate of the test coupons decreased with the logarithm of distances from the coastline. The corrosion of the test coupons was accelerated at the places of the high humidity such as around cooling towers. It is thought that the atmospheric corrosion test with the adhesive-backed test coupons is effective as technique to evaluate the tendency of an environmental corrosiveness in factory sites.