Precise practical estimation of the expansive strain distribution in cross-sectional dimension is important for effective use of CPC(Chemically pre-stressed concrete) members, but previous studies have reported only the expansive strain distribution of CPC members having symmetrical arrangement of reinforcing bars and cross-sectional dimensions. In this study, we report the estimation method and the experimental results of the expansive strain distribution of CPC members with non-symmetrical rebar arrangement in T-shaped and L-shaped cross sections. The value of the expansive strain estimated by the proposed cross-sectional analysis from the expansive strain of the JIS specimen is goodly corresponded with the experimental value using the Work-done concept.
The amount of CO2 absorbed in cementitious materials using blast furnace slag and γ-2CaO·SiO2 partially instead of cement and carbonation curing was evaluated by various analytical methods. As a result, it was shown that inorganic carbon analysis is more suitable than thermal analysis to evaluate the amount of CO2 absorption in concrete. In addition, it was shown that the concrete using blast furnace slag and γ-2CaO·SiO2 can absorb large amount of CO2 during carbonation curing. Furthermore, it was confirmed that porosity and compressive strength of the concrete equal to or higher than those of ordinary concrete can be obtained by improving the reaction of blast furnace slag due to the high temperature during carbonation curing and densifying the pore structure due to carbonation of γ-2CaO·SiO2.
The carbon fiber grid bonding methods with reinforcing effects certified by the wheel load running tests conducted on ordinary RC slabs, are often adopted for anti-aging reinforcement of lightweight RC slabs using lightweight aggregates. In order to verify its applicability, the wheel load running tests were conducted for lightweight RC slabs without and with reinforced by the carbon fiber grid bonding methods. In addition to the abovementioned test results, this paper examines the reinforcing eras and effects in comparison with the fatigue damage situations of the existing lightweight RC slabs. As a conclusion, there are certain reinforcing effects of the carbon fiber grid bonding method for lightweight RC slabs, and the acquired correlation between the reinforcing eras and effects suggests that reinforcing should be implemented before crack density increases.
In order to ensure the durability of cast-in-situ prestressed concrete road bridge deck in an environment where deicing salt is sprayed, we examined the workability of fly ash concrete on the premise of local production for local consumption and implemented it on highway road bridge. As the evaluation procedure of fly ash concrete, 1) laboratory test, 2) workability confirmation test using site mock up deck, 3) laboratory test for problem solving from the workability confirmation of site mock up deck, 4) actual concrete mixing plant test for final confirmation were conducted. And the mix proportion of fly ash concrete that satisfies the required performance for construction on site was decided from the evaluation procedure. As a result, it was found that the loss of slump and air content during transporting from ready-mixed concrete factory to site was remarkable in the fly ash concrete using both early-high-strength Portland cement and fly ash. Therefore, at the time of mixing fly ash concrete at the ready-mixed concrete factory, it is decided that properly setting the amount of increase in slump and in air content in anticipation of the slump and air content of arrival time at the site is needed. In addition, since the fresh properties such as slump and air content after pumping fly ash concrete in the implementation work were good, it was clarified that fly ash concrete can be applied to cast-in-situ prestressed concrete road bridge deck.