Research On The Durability Of Coastal High-speed Passenger Railway Concrete

Concrete is not the durable material being efficacious forever, and its project also has certain service life. Concrete structure may age and Lower durability gradually under long-term natural environment and severe service conditions, that may affect its function and security. The coastal railway transportation special line belongs to the national important lifeline project, once destruction or termination, Will bring massive loss to our country. Therefore the research of concrete durability, how to lengthen its service life, is the most important and most realistic topic suspended in front of all research workers.The massive research shows that: Activeness mixtures such as fly ash and slag take the place of cement partly, can not only save plenty of money, but also improve distinctly the durability of concrete. On the basis of ZhongTieShiSanJu high-speed Passenger railway project, the main research work and compliments of this paper are:The choose of raw materials, designation and the quality control method of coastal high -speed Passenger railway concrete are put out; the effect of mineral admixtures on mechanical property and durability of coach concrete are done; the influence of double mixing with fly ash and fine slag to penetration resisting and sulfate corrosion resisting are researched by chloride ion dielectric flux experiment; the effect of mineral admixture on the mechanism and workability, mechanical property, and anti-chloride osmosis of marine concrete is discussed amply; model is established to forecast and the analysis the durable life of concrete based on the second law by Fick.Result shows that: a) fly ash and fine slag can increase certainly slump of concrete, while decrease its loss of slump, improve the mechanism and workability obviously of high speed Passenger railway concrete. b) Water ratio has significant influence to dielectric flux in six hours, while lower the water ratio, the numerical value of dielectric flux in six hours can be reduced to no more than 1000, which means the concrete has very high penetration resisting. c) Mineral admixtures fill in the limestone hole, stop up the capillary vessel channel, compact the concrete structure, the concrete mixed by fly ash and fine slag has lower numerical value of dielectric flux in six hours. d) The anti-sulfate corrosion experiment also indicates that, the mixing in of active mineral admixtures such as fly ash and fine slag, has relatively reduced the content of C3A, phased down the possibility of sulfate corrosion, the second hydration effect of active minerals response not only to absorb massive Ca (OH) ₂, but also weaken the effect of contact surface of limestone, all of these factors enable the concrete have better anti-sulfate corrosion performance. e) preliminary estimate to the life of concrete is done based on the chloride ion permeability, result shows, double mixing fly ash with fine slag, the concrete has a higher durable life, while reducing the water cement ratio, optimization matching technology of mineral admixtures, The concrete life may amount to above for 100 years.