Comparative Study of the Pore Structures and Surfaces of Hardened Cement Pastes of Potential Use in Radioactive Waste Repositories

摘要

Measurements of water vapor adsorption at 20 deg C and mercury intrusion have been used to compare the surfaces and pore structures of hardened cement pastes made from ordinary portland cement (OPC) and the additives blast furnace slag (BFS) and pulverized fuel ash (PFA). The results suggest that each additive, after taking part in the hydration reaction with OPC, produces a paste whose gel pore structure is similar to that derived from OPC alone. The BET adsorption surface area of the cement pastes, in the form of half inch diameter coupons was ca. 55 m sup 2 g sup -1 and was not influenced by the presence of the additives. However the pastes containing the additives have a larger and better interconnected meso and macropore structure than OPC which may account for larger diffusion coefficients reported elsewhere for cesium ions passing through concrete containing BFS in comparison with a concrete containing OPC alone. (ERA citation 13:035832)