Mix Design And Bond-slip Performance Of Sea Sand Coral Concrete

Due to the long-term effects of corrosion,load and other factors on maritime buildings,if ordinary reinforced concrete structures are used,the transportation costs of construction materials will be too high and the construction service life will be too short.Based on the above circumstances,in order to better speed up the maritime buildings,this article studies the use of maritime and coastal local corals and sea sand to replace ordinary stone coarse aggregate and river sand fine aggregate to fully protect the environment and save resources.The FRP bars are then used to replace the steel bars,thereby better solving the problem of the steel bars being corroded in the working state with chloride ions,and prolonging the service life of the building.The main research contents of this article are as follows:1.The basic physical properties of coral coarse aggregates under three gradations were studied.The results show that the coarse aggregate gradation is 5 ? 10 mm coral debris + 10 ?25mm coral cylinder pressure strength is about 5% higher than that of 10 ? 25 mm coral,and the coarse aggregate gradation is 5 ? 10 mm coral sand + 10 ? The compressive strength of25 mm coral tube is about 14% higher than that of 10-25 mm coral.The three coarse aggregate gradations have a porosity of more than 50% and a water absorption of more than 14%.The basic physics of sea sand is similar to the basic physics of river sand.2.In this test,the laboratory mix ratio of C20-C50 sea sand coral concrete was obtained by making 378 standard cube compression members.The effects of cement content,coral aggregate gradation,water-cement ratio,and pre-wet coral on the compressive strength of sea sand coral concrete were compared and analyzed.It is obtained that the strength of sea sand coral concrete increases with the increase of cement content in this test range;the coarse aggregate gradation uses 5 ? 10 mm coral sand + 10 ? 20 mm coral,and the strength is highest;the compressive strength of the pre-wet coral block is less When the water-cement ratio is within a certain range,the strength of the sea sand coral concrete increases with the decrease of the water-cement ratio.At the same time,the failure mode of the test specimen is analyzed.3.75 different FRP bars and sea sand coral concrete standard drawn test specimens were produced and tested for bonding performance.The study found that: within the scope of this test,the bond stress between FRP tendons and sea sand coral concrete increases with increasing concrete strength;as the diameter of FRP tendons increases,the bond stress gradually decreases;as the bond length increases,As the stress increases,the bond stress gradually decreases.At the same time,the failure mode of the drawn specimen in this test is analyzed.4.The bonding performance of sea sand coral concrete with GFRP bars and CFRP bars was comparatively analyzed;the bonding performance of sea sand coral concrete with GFRPbars and BFRP bars was compared and analyzed.The typical bond slip curve of this test is compared with the existing bond slip model,and the typical bond slip curve of this test is combined with Matlab scientific calculation language to obtain the bond slip model of sea sand coral concrete and FRP tendons..Finally,under purely theoretical conditions,a differential equation of bond slip between FRP bars and sea sand coral concrete was established.Through the analysis and research in this paper,we will fill in the basic research on the mix ratio of sea sand coral concrete in China and the bond slip performance with FRP bars,and lay the foundation for a more in-depth study of the application of sea sand coral concrete in practical engineering.