Research On Design And Performance Of High Performance Concrete Materials For XiaZhang Cross-sea Bridge

Due to the harsh service environment of marine engineering concrete structures, the structure often fails prematurely,causing significant economic losses.In the application of the cross-sea bridge,in order to ensure the safety of the cross-sea bridge structure and ensure that it has the ability to design and use,it is very important to conduct material design and performance research on offshore high-performance concrete.In this paper,combined with the example of the wet joint project of the deck of the Xia-Zhang cross-sea bridge,through analyzing the common diseases of the concrete structure,the technical characteristics of offshore high-performance concrete are obtained.According to the basic characteristics of offshore engineering high-performance concrete,determine its raw materials,test methods and design technical indicators,and perform concrete material design and performance tests on it,the test results meet the engineering use requirements,according to the obtained marine engineering high-performance concrete to Xia Zhang Construction of wet joints of bridge decks of sea-crossing bridges.The service environment of the concrete structure is harsh.Due to factors such as steel bar corrosion,sulfate damage,and freeze-thaw cycle damage,the durability of marine concrete is insufficient.Through internal measures such as material durability design,increased protective layer thickness,and the use of reinforced steel,anti-corrosion treatment,electrical External measures such as chemical protection and scientific maintenance management can improve the durability of marine concrete.The configuration of offshore engineering high performance concrete is different from that of ordinary concrete,and the requirements for raw materials are higher.Research on the raw materials of offshore engineering concrete,determine the raw materials required for the configuration of offshore engineering high-performance concrete and test the technical indicators.Through the combination of test and theory,select the appropriate test method and design technical indicators for field test.According to the design and use goals of offshore engineering high-performance concrete and the basic principles of preparing offshore engineering high-performance concrete,the design of the mix proportion of offshore engineering high-performance concrete in combination with the design regulations,based on the principles of durability and economy,the Xiazhang cross-sea The design scheme of marine high-performance concrete used in the bridge（cement:mineral powder:fly ash:sand:crushed stone:water:admixture:expansion agent=340:67:43:668:1134:150:7:50）.According to the design results of the marine high-performance concrete mix ratio,the marine high-performance concrete is mixed and the corresponding concrete test pieces are formed,and the relevant performance tests are conducted respectively.The slump value of the test is 180mm,and the slump expansion is 460mm,which meets the design requirements;the concrete has good fluidity,cohesiveness and water retention;the measured expansion rate of 14d in water is 3.9×10^-4 and 14d in water 2.The 28d limiting shrinkage rate in air is 1.5×10^-4;the 7d compressive strength is 62.0MPa,the 28d compressive strength is 71.2MPa,reaching 101.9%of the concrete test strength,and the28d compressive rebound modulus is 4.7×10⁴MPa;mechanical properties such as compressive strength,elastic modulus,durability against chloride ion penetration,and resistance to early cracking all meet the design and use requirements.Combined with the climatic conditions and engineering construction requirements of the Xia-Zhang Sea-crossing Bridge in service,using appropriate construction techniques,reasonable resource allocation,and quality control throughout the entire process,the bridge deck wet joints of the Xia-Zhang Sea-crossing Bridge Section VI contract were completed construction.In this paper,through the combination of testing and engineering practice,the design scheme for the mix ratio of marine high-performance concrete materials is obtained,and the performance test of the marine high-performance concrete obtained by the mix ratio design plan is carried out through relevant tests and successfully applied to the wet of bridge deck Seam construction.Through the research and design of the mix ratio of marine concrete and the evaluation of its performance,it will be of guiding significance for the subsequent construction of marine concrete structures and provide a certain reference for the development of marine high-performance concrete.