Study On The Relationship Between The Mechanical Variability Of Sea-sand Concrete And The Stress-strain Relationship Under Circular Constraint In Different Sea Areas

With the increasing shortage of building materials,when river sands are no longer adequately supplied,people turn their attention to the wider oceans.Rational development and utilization of marine resources has become the trend of human survival and development.China has a coastline of 18,000 kilometers in length and has a large number of large and small islands.The construction of buildings on the islands in the outer suburbs requires a lot of concrete,but the resources of the island are scarce.These concretes are often transported by sea from the mainland,but this method is time consuming and laborious.Considering that the island has unique marine resources,if the sea sand and seawater can be used to replace the fine aggregate and fresh water resources needed for mixing concrete,it will greatly increase the building efficiency and save river sand and fresh water resources.In this context,this paper studies the basic mechanical properties of concrete prepared from sea sand and seawater in different sea areas around Shenzhen City,and expects to do its part to promote the use of undisturbed sea sand concrete.The details are as follows:(1)In this paper,sea sand tests were first performed on the sea sands in Neilingding Island sea area of Shenzhen,sea sands in Daya Bay of Huizhou,and sea areas of Shenzhen Pearl River Estuary,and the concentrations of major ions in sea water in three sea areas were also tested.Then seawater and seawater concrete and desalinated sea sand freshwater concrete were prepared with the same mix ratio.(2)By testing the 28-day intensities of the cubes,mathematical analysis was performed on 30 samples in each group and the population was estimated.The conclusion is that the strength of the concrete prepared from sea sand and seawater is about 2% lower than that of conventional concrete.-12%;Test sea-sand-water-salt concrete short column 28 d and 56 d in-situ stress-strain curves,curve shape no difference with ordinary concrete,but at the same age,the strength,elastic modulus,peak strain of traditional ordinary concrete are Slightly larger than sea-contaminated sea-water concrete;as the age increases,the difference between strengths continues to increase,and the difference in elastic modulus and peak strain no longer change.(3)The FRP confined sea-contaminated sea-water concrete experimental study was carried out: the influence of the number of FRP enveloping layers on the ultimate performance of sea-sand-contained seawater concrete was analyzed: the ultimate strength improvement of sea-sand-seawater concrete under FRP confinement was 43% to 105%.The ultimate strain increase ranged from 388% to 776%.The ultimate strength model,ultimate strain model and stress-strain constitutive model of CFRP confined sea-contaminated seawater concrete were established.The experimental data were used to test the prediction results of the model.It was found that the fit was high.