The Experimental Research On Antibacterial Properties Of High Performance Concrete With Nano-zinc Oxide

This paper aimed at the durability of concrete and to improve the problem of antibacterial proterty, by viture of the micronized gradation effect with incorporation of fly ash, slag and polypropylene fiber and the antibacterial property of nano ZnO, adapted methods of orthogonal test and comparative test, made a systematic study on the durability and green antibacterial of concrete with complex admixture by the research tools of macroscopic and microscopic test. The main results are as follows:(1) Orthogonal test:choose the optimal set of concrete mix ratio for A2B1C2D3E1, namely water-cement ratio is 0.34, the percentage of fly ash is 10%,the percentage of slag is 20%,the ratio of sand is 40%, the percentage of polypropylene fiber is 0.55kg/m3.(2) Test for carbonation performance of concrete:the increasing of carbonation resistance of concrete with the increasing of age. The incorporation of fly ash, slag and polypropylene fibers optimized the internal pore structure of concrete, reduced the porosity, and made good performance of the anti-carbonation, but with the latter reaction between the ash and cement hydration products of Ca (OH) 2,and weakened the carbonation effect. With adding nano-ZnO, partial ZnO reacted with hydration products then producted ZnCO3 and CaZn2 (OH) 6·2H2O,which were attached to the surface of hydration products and weakened resistance of carbonation.(3) Test for resistance to sulfat attack:sulphate resistance of concrete increases along with the age increases; The incorporation of fly ash, slag and polypropylene fibers played the role of filling and optimized the internal pore structure of concrete, reduced the porosity, improved the density, inhibited the diffusion of SO42-, meanwhile, buffered and weakened the expansion properties of concrete and the rate of the corrosion. With adding nano-ZnO, lots of ZnO were attached to the surface of hydration products and increasesed concrete porosity, exacerbated infiltration and diffusion of SO42-, which resulted sulfate corrosion to further, and sulphate resistance capacity decreased by 6.74% and 5.35%.(4) Test for antimicrobial property of concrete:through qualitative test of high-performance concrete with adding nano-ZnO to Escherichia coli and Staphylococcus aureus, which proved the antibacterial ability to the two strains. Made quantility test for performance concrete with adding ZnO on Escherichia coli and Staphylococcus aureus proved the rate of two antibacterial concretes against Escherichia coli antibacterial were 100% and against Staphylococcus aureus were 54.61% and 99.12%.