Study On Mechanical Properties Of Calcareous Sand Concrete

It is normal to carry out infrastructure construction on calcareous islands and reefs,Most of the island reefs are far from the mainland,and the inorganic materials needed for construction will greatly increase their construction costs if they are transported from the mainland.Such as the use of calcareous sand as fine aggregate in concrete,its drawing easy and low cost,can greatly save costs,save construction period.Calcareous sand has the characteristics of low strength and easy to break,which will inevitably make the mechanical properties of calcareous sand concrete different from conventional concrete.Therefore,In this paper,calcareous sand was used as a test sample to test the basic mechanical properties of calcareous sand,conventional triaxial test of calcareous sand concrete and fiber reinforcement effect,and the deterioration effect of dry and wet cycle on the mechanical properties of calcareous sand concrete.It has important theoretical significance and application value for the construction of calcium project.This paper mainly studies the following aspects:(1)Calcareous sand compaction test carried out to obtain the maximum dry density and optimum water content.Further study on the crushing of calcareous sand after compaction;Conduct a direct shear test to investigate the effect of dry density and moisture content on shear properties.Tests were studied Bearing Ratio(CBR)and other,The test results show that there are different sizes of cohesion in calcareous sand.This is mainly caused by the different surface morphology of calcareous sand,the formation of bite force,the capillary action of water in sand and the cementation phenomenon of cementation between particles.The cohesive force of calcareous sand decreases linearly with the increase of water content,and increases with the increase of dry density.The internal friction angle increases slowly with the increase of the dry density,and fluctuates slightly with the increase of the water content.Through these experiments,we will have a deeper understanding of the engineering properties of calcareous sand.Thereby providing reference for engineering practice such as island facility construction.(2)Preparing calcareous sand as fine aggregate and adding basalt fiber concrete,The standard curing concrete have been polished like a standard drill soil sample,a triaxial different confining pressures and compression tests of different Basalt fiber content.The results showed that: Under the same confining pressure,with the increase of fiber content,the peak stress of calcareous sand concrete first increased and then decreased,and the peak strain increased with different degrees.With the same fiber content,the peak stress and peak strain of calcareous sand concrete increased with different degrees with the increase of confining pressure.(3)Making basalt fiber reinforced calcareous sand concrete into standard triaxial specimens,Dry and wet cycles in artificial seawater,The results obtained are compared with ordinary triaxial tests.The effect of dry-wet cycle on the compressive strength of basalt fiber-reinforced calcareous sand concrete,And as the number of dry and wet cycles increases,the peak stress of calcareous sand concrete decreases to varying degrees.The deterioration effect of dry and wet circulation on calcareous sand concrete is obvious under low confining pressure.