A Study on Estimation Method of Curing Influence Area for Prediction of Remaining Life on Real Concrete Structures

The life cycle of concrete structures is known to be highly dependent on the manufacturing, construction and the environment of the structure’s location. In order to keep the durability of concrete, it is necessary (1) determination of materials and mix proportion on design, (2) keeping the enough compaction and curing period on construction and (3) understanding the environmental effects such as supply of carbon dioxide, chloride ions and water. Therefore, it is important to implement the design with the required performance to satisfy the design service life. On the other hand, in maintenance management, it is necessary to predict the remaining life based on the supplying period and the state of deterioration at that time. In this case, the information at the time of design and construction is often unknown, and it is difficult to estimation. In this study, as a first step to sort out these issues, concrete specimens were prepared using various types of cement, varying the water cement ratio and also varying the curing period. The accelerated carbonation test and vacuum water absorption test were combined to represent the penetration of carbon dioxide and water in the specimens. The area of influence of curing was organized in terms of material and mix proportion conditions. Porosity was also measured to evaluate the relationship between the penetration properties. In addition, wall specimens were also prepared to measure the effect of curing by non-destructive test. As a result, it was confirmed that the larger the water cement ratio, the greater the effect of curing on the surface layer, but the depth of curing effect was about 20 mm. It was also confirmed that the effect of curing and curing area were larger for Low heat Portland cement and high replacement blast furnace slag cement, where the hydration would slower.