Design Of High-performance Concrete And Application It In Tongchuan-Huangling Highway Bridge Concrete Engineering

Most of the sections of the Tong-Huang Expressway are the loess plateau,the gully and the loess gully,the environment is harsh and complex.The environment is harsh and complex,and the local climate is dry,the temperature difference between day and night is large,steep ditch steep slope,water erosion and gravity erosion are common phenomena.High performance requirements for the basic engineering of the area,especially for bridge structure concrete materials.Based on this,this paper combines local rich fly ash and mineral resources to study and design high-performance concrete that meets the construction requirements of the Tonghuang expressway bridge project.The effects of mineral admixtures,compatibility and content on the performance,mechanical properties and durability of high performance concrete were studied.The main contents of this paper are as follows:(1)Investigation and study of the geological environment and climatic conditions in the area where the Tong-Huang Expressway was located and the disease of the local bridge structure.The causes of various diseases are analyzed and summarized,so as to prepare for the research and design of high performance concrete for tonghuang expressway bridge.(2)The technical properties of all raw materials(cement,aggregates,additives and mineral admixtures)were tested,and corresponding raw material quality control parameters were proposed.Based on the environmental characteristics along Tonghuang Highway and the research results and pre-tests of high-performance concrete,the corresponding test method was optimized.(3)The design method of high performance concrete mix ratio is summarized and analyzed.The full calculation method is selected as the concrete mix proportion design method for C35~C50 bridge engineering,and the preliminary concrete mix ratio calculated according to this method is combined with the key parameters of the mixture ratio,including the water gel ratio,the amount of cementitious material and mineral admixture.The study of concrete performance and mechanical properties has obtained the mix proportion of C35~C50 high performance concrete.(4)The effects of mineral admixtures on the durability of high performance concrete including dry shrinkage,frost resistance and sulfuric acid corrosion resistance were studied.The mechanism of mineral admixture on the mechanical properties of high performance concrete is analyzed by means of microscopic test.(5)The engineering application results show that the high-performance concrete developed in this paper has been applied perfectly in the Tong-Huang Expressway bridge project,and the working performance,mechanical performance and durability have all achieved the expected results,and it has the effect of shortening construction period and reducing costs.