Research Of Improve The High Performance Concrete Anti-Chloride Permeability

High Performance Concrete (HPC) is a kind of environmental and intensivism material, which is a breakthrough to the traditional concrete. It has significances in saving source and material, engineering Economics, labor force protection, and environment protection etc. It is a new milestone for the development of the concrete history. The 21^st century is the epoch of the HPC.Permeability of chloride ion is an important index to assess both the high durability of concrete, and the corrosion resistance of the steel bar in the structure of the reinforced concrete. Combining with the development and the research fruit of the concrete from home and abroad, this article puts forward to use fly ash and slag powder to improve the durability of concrete. In order to confect the concrete with excellent capability, the course contrasts two kinds of Water-cement ratios, 0.36 and 0.5; permutes cement with the same amount substitution from using different parameter of fly ash, slag powder, concrete mixed with fly ash and slag powder, then add fly ash and high-capability water-reduce dose. the aim is to improve the permeability resistance of chloride ion of the high performance concrete. Moreover, it makes trials for the concrete in the basic mechanical capability and diffusion modulus of chloride ion. It adopts NEL for the trial of the diffusion modulus of chloride ion.From the research, it is found that the concrete will be have excellent working and mechanical capability after being mixed with the coal ash, the slag powder and the admixture of fly ash and slag powder. The 28-day age intensity of the concrete is the quite the same as the benchmark, and it will be better after put into slag powder. In the aspect of permeability resistance, diffusion modulus of chloride ion mixed with admixture is more excellent than the benchmark. It can improve one or two levels for the permeability resistance of the concrete. The level will be different as per the parameter.The article has set up the equation of the mineral admixture and the parameter of the diffusion of the chloride ion according to the numerical analysis of the experiment data. Through microcosmic analysis, it analyses the change of the hydration products and the pore-structure after the concrete intermingled with mineral admixture and expounds the reason of the trial result from physics and chemistry.After above analysis, it gives the suggestion on utilizing the fly ash the slag powder in confecting the excellent capability of the concrete and gives the measures to improve the permeability resistance of the concrete.