Studies about the resistance of carbonation capability of fly-ash (FA) concrete at different initial curing regimes and exposure time through accelerated carbonation experiments were made. Firstly, 30% replacement ratio fly-ash concrete specimens were fabricated and cured in 20°C, 30°C and 40°C water for 3d, 7d, 14d and 28d respectively, and cured in a standard air environment (20±2°C, relative humidity ≥95% ) for 28d. As a comparison, ordinary Portland concrete (OPC) specimens were also made and cured in 30°C water for 7d, and standard curing for 28d. After the initial curing, all the specimens were taken out and placed indoor natural environment. When specimen age reach 30d, 60d and 120d, 2 weeks accelerated carbonation experiments were made and concrete carbonation depth were measured. In addition to this, hydration degrees of fly ash at different initial curing conditions were measured using the selective dissolve method. Results show that the initial curing conditions play an important role in the carbonation resistance of FA concrete. Initial water curing is beneficial to the development of carbonation resistance of FA and OPC concrete. Prolonging initial curing time and increasing curing temperature is beneficial for the carbonation resistance of FA concrete. For the same curing conditions, carbonation rate of FA concrete is usually higher than OPC concrete, but with the increase of initial curing temperature, the difference can be reduced.
Based on the similarity theory, a new experimental method named Similar Experimental Method for Durability of Concrete (SEMDC) was established. The existing experimental methods for durability of concrete were summarized, and the merits and demerits of these experimental methods were analyzed. Major factors affecting the durability of concrete were found through literature review. These factors were analyzed and the similarity criteria were established according to the similarity theory, and then the SEMDC was established according to the rules of these criteria. The various influential factors of the experimental method were analyzed and the merits and demerits of this new experimental method were discussed. According to SEMDC, changing the geometry shrinkage ratio was the only way to accelerate the test in order to keep the experiment similar to the reality. There were few other parameters which need to be changed in SEMDC, making the test easy to be achieved. According to SEMDC, time shrinkage ratio was the square of geometric shrinkage ratio, so an appropriate increase of the geometric shrinkage ratio could accelerate the test. Finally, an example of experimental design for durability of concrete was devised theoretically base on SEMDC theory.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.