Study On Materials And Mechanical Properties Of Plastic Concrete Diaohraam Wall

Plastic concrete refers to a kind of impervious wall material made of bentonite(or clay),fly ash and other admixtures instead of part of cement.Plastic concrete is widely used in hydraulic engineering because of its good compatibility with foundation deformation and impermeability.Since plastic concrete diaphragm wall was put into use,a series of researches on plastic concrete diaphragmwall have been carried out at home and abroad,but there are still some shortcomings in some aspects.At present,there is no specification for mix design of plastic concrete in China,and the research on age prediction and strength index conversion of plastic concrete is still lagging behind.In view of the above problems,the main research contents of this paper are as follows:(1)In view of the site working conditions of the second stage cofferdam of Datengxia Hydro-junction Project,the relevant performance index requirements of anti-seepage materials are put forward.Based on the previous relevant engineering experience,a reasonable mix ratio test is designed by engineering analogy method,and determines the basic performance of the mix ratio of each group to choose the optimal mix ratio.(2)The permeability and triaxial tests of the specimens satisfying the criteria are carried out and the influence of age on permeability coefficient is analyzed according to the permeability test results,and the related problems of strength parameters and failure shape of plastic concrete are discussed according to the results of triaxial test,and the influence law of age on triaxial compressive strength of plastic concrete is analyzed.(3)The effects of cement content,clay content and bentonite content on the performance(mainly slump and diffusivity),strength,and modulus of elasticity and modulus-to-strength ratio of plastic concrete mixtures were studied through the performance test of plastic concrete mixtures.(4)On the basis of cubic compressive strength tests of 66 cubic specimens of 150 mm x 150 mm x 150 mm and compressive elastic modulus tests of 66 150 mm x 300 mm cylinder specimens,the influence factors of cement content,clay content and bentonite content on the strength,modulus of elasticity and modulus-strength ratio of plastic concrete were studied.(5)On the basis of cubic compressive strength tests of 66 cubic specimens of 150 mm x 150 mm x 150 mm at 7d,28 d and 90 days of age,the influence of age on uniaxial compressive strength of plastic concrete is analyzed,and the relationship between the strength of plastic concrete at 7d～28d～90d and age is further fitted.(6)On the basis of the cube compressive strength test and the cylinder compressive strength test of 22 groups of mixture ratio,the relationship between the cube compressive strength and the cylinder compressive strength is obtained,and the relationship between the cube compressive strength and the cylinder compressive strength is established.