Experimental Study On The Axial Compressive Properties Of FRP Bars/Anticorrosive Steel Sea Sand Concrete Columns Under Marine Environment

With the development of china's maritime power strategy,the pace of the china's marine and coastal engineering construction have gradually accelerated.However,the river sand resources are becoming exhausted,and the blind use of sea sand may cause serious corrosion of concrete components.Therefore,it is very important to reasonably develop and use sea sand resources.China has a long coastline.How can we take sand in situ and use sea sand instead of river sand.Not only can alleviate the lack of river sand resources in coastal areas,but also solve the problem of long-term sand and gravel supply in the construction of marine island and reef,which is more conducive to saving resources and protecting the environment.Therefore,it is necessary to conduct in-depth research on the properties of the returned sea sand material,the basic mechanical properties of the sea sand concrete,the anticorrosive design of the sea sand reinforced concrete columns,and the axial compressive performance of the GFRP reinforced sea sand concrete columns.This article mainly designed 60 sea sand concrete cube test blocks,9 cylinder test blocks,30 sea sand reinforced concrete short columns and 10 GFRP reinforced sea sand concrete short column axial compressive test specimens.21 specimens were subjected to seawater immersion test in the ocean wave splash area and compared with ordinary sea sand specimens.Then all the specimens were subjected to static loading tests to analyze their mechanical characteristics.From the static loading test of the specimens,the failure form of the specimens was observed,the load-displacement curve of the specimens was obtained,the characteristic point parameters such as peak load,peak displacement,initial stiffness and ductile energy consumption were acquired.The influence of design parameters(sea sand replacement ratio,mixing water,reinforcement ratio,hoop ratio,wave splash age,admixture ratio and rust prevention measures)on the axial pressure performance of the specimens in the marine environment was analyzed.The results show that the mixing water,the reinforcement ratio,the hoop ratio,wave splash age and the outsourcing PVC antirust measures have a significant effect on the axial compression performance of the sea sand concrete short column.The replacement ratio and admixture ratio parameters have little effect on the mechanical properties of the specimens.Finally,based on the results of the axial compression test,the calculation method of the axial compression bearing capacity of the reinforced sea sand concrete column,PVC pipe reinforced sea sand concrete column and GFRP reinforced sea sand column under the ocean environment is discussed based on the standard formula.Considering the strength degradation of the material with the age of wave splashing,the material strength correction factor is introduced to correct the calculation formula of the normal section bearing capacity of the sea sand specimen,and the calculation results are in good agreement with the test values.