Exposure Test on Two Surface Anticorrosion Technologies for Marine Concrete Structure

This paper is to study the effect of surface coating and silane hydrophobic agents for high performance concrete durability in a marine environment of tidal zone and splash zone by exposure test in JiaoZhou Bay. The results indicated that surface coating had good protection and coating quality after a 5-year period and the adhesive strength with concrete surface was more than 2.5 MPa. Surface coating can effectively improve chloride ion penetration resistance of concrete structures. The substrate concrete of specimen treated with silane had some chloride ion penetration, but compared with untreated concrete, chloride content of silane-treated concrete within 10 mm depth from surface was reduced by 43 and 67% in the tidal zone and the splash zone, respectively. Two surface anticorrosion measures technologies were effective in reducing the chloride erosion and improved the service life of marine concrete structure

Water–Binder Ratio Monitoring as a Quality Control Tool for the High-Performance Concrete Used in the Construction of the Submerged Tunnel

The designed service life of Hong Kong-Zhuhai-Macao Bridge is 120 years. Concrete quality control for the submerged tunnel of the project is an important work to assure the designed service life. This article is to present an advanced concrete performance prediction method based on water–binder ratio (w/b) monitoring, which is used to serve for concrete quality control. During experiments in the lab, the w/b of submerged tunnel concrete mix proportion was designed to fluctuate up and down, while the other compositions were kept constant. Concretes with different w/b were prepared. The w/b of fresh concrete was tested, followed by preparation of specimens for compressive strength and chloride diffusion coefficient tests. The compressive strength and chloride diffusion coefficient of the hardened concrete were tested. Relationships between the tested w/b and the compressive strength and chloride diffusion coefficient were established. The fitting curves were taken as the prediction models. During construction of submerged tunnel in field, w/b of fresh concrete was tested. The compressive strength and chloride diffusion coefficient of the concrete were calculated using the established models. In addition, specimens of the tested concrete were prepared and cured for compressive strength and chloride diffusion coefficient tests. Finally, the predicted results and the tested results were analyzed, and the predicted deviation was calculated. Results of the calculations show that the prediction deviations of compressive strength and chloride diffusion coefficient ar

Water–Binder Ratio Monitoring as a Quality Control Tool for the High-Performance Concrete Used in the Construction of the Submerged Tunnel

The designed service life of Hong Kong-Zhuhai-Macao Bridge is 120 years. Concrete quality control for the submerged tunnel of the project is an important work to assure the designed service life. This article is to present an advanced concrete performance prediction method based on water–binder ratio (w/b) monitoring, which is used to serve for concrete quality control. During experiments in the lab, the w/b of submerged tunnel concrete mix proportion was designed to fluctuate up and down, while the other compositions were kept constant. Concretes with different w/b were prepared. The w/b of fresh concrete was tested, followed by preparation of specimens for compressive strength and chloride diffusion coefficient tests. The compressive strength and chloride diffusion coefficient of the hardened concrete were tested. Relationships between the tested w/b and the compressive strength and chloride diffusion coefficient were established. The fitting curves were taken as the prediction models. During construction of submerged tunnel in field, w/b of fresh concrete was tested. The compressive strength and chloride diffusion coefficient of the concrete were calculated using the established models. In addition, specimens of the tested concrete were prepared and cured for compressive strength and chloride diffusion coefficient tests. Finally, the predicted results and the tested results were analyzed, and the predicted deviation was calculated. Results of the calculations show that the prediction deviations of compressive strength and chloride diffusion coefficient ar