Abstract: Effective improvement of the impermeability of hydraulic anti-seepage concrete structures is the key to durability enhancing. In this work, we conduct impermeability tests on hydraulic concrete mixed with Bacillus Coriolis, and analyze the influence of the additive concentration on impermeability. Through nitrogen adsorption tests, we examine the micro-pore characteristics of concrete samples, and reveal the influencing mechanism of Bacillus Coriolis on impermeability. The results show the impermeability of concrete can be significantly improved by adding mineralized microorganisms. With the increase in microbial concentration, the water permeability coefficient of the 28 d concrete samples tends to decrease sharply and then slowly; at a microbial concentration of 9.8×107 cells/mL, the decrease of 92% is the largest. Micro-analysis of nitrogen adsorption shows that adding microorganisms into concrete reduces the number of medium- and large-size pores and refines the concrete pore size, and that the peak diameters of the most probable holes are reduced by up to 47.7%. This improves effectively the pore structure in hydraulic concrete and reduces its pore connectivity, thus enhancing its impermeability significantly.

Key words: hydraulic concrete, anti-seepage body, imper