| Summary: | 博士 === 國立中央大學 === 土木工程學系 === 102 === Reactive powder concrete (RPC) has been proposed as barrier materials for the construction of engineered barrier in Taiwan. The durability characteristics of RPC in such applications become paramount for the success of the containment of the wastes. The adverse environmental conditions at the disposal site could attack concrete barrier material and results in degradation of the material. Laboratory tests were conducted on RPC with various compositions to investigate the physical and engineering characteristics of RPC. In this study, curing of specimens at elevated temperature of 80℃ accelerated the hydration processes of concrete and thus exhibited higher compressive strength. However, it is accelerated the hydration processes of concrete and thus exhibited higher compressive strength. The resistance of concrete to sulfate attack were tested by submerging RPC specimens submerged in Na2SO4 solution. Based on the volume change data in 12 months, specimens without steel fiber showed greater length changes than those with steel fiber. Also, RPC with higher water to binder ratio (W/B) exhibited lower resistance to sulfate attack. According to the test result, the internal structure of RPC having low W/B and blended with pozzolanic materials is comparatively denser, leading to the low diffusion coefficient under the attack of chloride ions. Bonded chloride ions may constantly accumulate at the surface of concrete within about 3 mm depth from surface. Experimental results indicate that the long-term durability of RPC is significantly improved with the hydration of pozzolanic materials, which produces a very dense structure and thus exhibiting improved durability.
|
|---|
