Preparation Technology of High Durability Fair-faced Concrete for Qingdao Rail Transit R3 Line Station
Based on Qingdao Rail Transit R3 Line,raw materials were selected according to the technical requirements of the fair-faced concrete components,and concrete mix ratio tests were carried out to analyze the effects of single mineral powder,double mineral powder+fly ash,as well as triple mineral powder+fly ash+silica powder on the performance and appearance quality of fair-faced concrete.The experimental results show that compared with single mineral powder,double mineral powder+fly ash,triple mineral powder+fly ash+silica powder can significantly improve the workability of concrete,ensure the compressive strength of concrete at 28 d,significantly reduce electrical flux,and improve the durability and appearance quality of concrete.The mix proportions of different strength grades of concrete were designed and the concrete was prepared using a method of adding triple mineral powder+fly ash+silica powder.After testing,the workability of concrete of different strength grades is good.The gas content is at 2.3%～2.4%,which could meet the technical requirements.The compressive strength meets the requirements of each strength grade.The electrical flux for 28 d is at 420～480 C,which is with good durability performance.The appearance color is uniform,the glossiness is good,and there are no obvious bubbles.The prepared fair-faced concrete has been applied in Lianghe Station and Lingshanwei Station of Qingdao Rail Transit R3 Line.The appearance quality of fair-faced concrete in various parts could meet the requirements of JGJ 169-2009 Technical Specification for Fair-faced Concrete Construction,and the engineering application effect is good.
rail transitfair-faced concreteraw material selectionmix proportion designdurability performanceappearance quality
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