PERMEABILITY OF HYBRID CONCRETE FOR SUSTAINABLE BRIDGE DECK PAVEMENT

초록

The purpose of this paper was to investigate the effect of latex and silica fume in hybrid concrete containing organic latex and inorganic silica fume. To obtain this goal, a series of rapid chloride permeability tests were performed according to ASTM C 1202 with the main experimental variables of latex contents ( 3, 5 and 7%) and silica fume contents ( 6, 7 and 8%). The compressive strengths of hybrid concrete were measured to be between 38 and 44MPa at 28 days and 41 to 50 MPa at 56 days. The flexural strengths were measured to be between 5.9 and 7.5MPa at 28 days. The permeability of hybrid concretes is very low at all mixtures. The passed charges were less than 600 Coulombs at 56 days for all mixtures, which is categorized as a "very low" permeable material according to the criteria indicated at ASTM C 1202[2]. This "very low" category is obtained at a latex-modified concrete or internally-sealed concrete, which means that the hybrid concrete is well internally sealed by latex film and filled by finer silica fume. The rapid chloride permeability was not affected by air content nor spacing factor, even though all mixtures showed 'very low' permeability. This might be explained by that the structure of the paste of latex-modified concrete is such that the micro pores and voids normally occurring in Portland cement system are partially filled with the latex film that forms during curing.

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