Study On The Performance Evolution Of Cut-off Concrete Cementitious Materials Under The Action Of Dissolution

The concrete cut-off belongs to the foundation concealed project.Its safety monitoring equipment is buried deep under water,the working environment is complex,and the reliability is difficult to be guaranteed.In addition,the concrete of the anti-seepage wall is vulnerable to environmental water corrosion damage during the service process,resulting in the anti-seepage wall.The performance is degraded,which is very unfavorable for the long-term safety of the project.Therefore,it is necessary to carry out research on the performance evolution of the cut-off wall concrete under the action of dissolution.Since concrete is a multi-phase composite material and its structure is complicated,many studies have shown that hardened cement gel is the most important factor determining the anti-seepage and anti-corrosion ability of concrete.The hardened cement gel structure is relatively simple and homogeneous,and has good feasibility.Studying the performance evolution of the hardened cement gel under the action of dissolution can provide technical guidance for the design,construction and long-term safety assessment of the anti-seepage concrete.Therefore,this paper intends to carry out research on the performance evolution of concrete anti-seepage wall gel under the action of dissolution.This will have significant theoretical and practical significance for the improvement of concrete material for anti-seepage wall in the future and prolong the service life of the structure.The main contents and conclusions of the paper are as follows:(1)Study on the performance evolution and dissolution mechanism of gel specimens with different water-to-binder ratio and cement fineness under the action of dissolution,and analyze the influence of water-to-binder ratio and cement fineness on the corrosion resistance of specimens.mechanism.The results show that with the dissolution,the calcium ion solubility of the hardened cement gel increases gradually,which leads to the loss of the quality of the test piece.The porosity of the corrosion zone gradually increases,the corrosion depth deepens,the tensile strength decreases gradually,and the impermeability,The corrosion resistance decreases gradually,and the square root of the dissolution depth and the dissolution time are linearly fitted.In the same dissolution environment,the water-gel ratio of the gel is larger,the fineness of the cement particles is lower,the appearance damage,mass loss,calcium ion dissolution The deterioration of the amount,the porosity of the dissolution zone,the depth of dissolution,the loss rate of the tensile strength,and the permeability coefficient are more serious.(2)The calculation method of equivalent porosity is established based on the porosity test data of the dissolution and non-erosion areas.The permeability model of the hardened cement gel capillary porosity and permeability measured by Powers was combined with C Sharp and cubic spline interpolation method to prepare the permeability solver.The test results of the permeability coefficient were found to be: the porosity of the dissolution zone gradually increased.The impermeability of the part has a linear degradation effect;the connectivity of the pores and the porosity opening have a greater influence on the permeability of the hardened gel than the porosity.(3)Based on the ultrasonic non-destructive testing method,the relationship model between dissolution depth,equivalent porosity and relative ultrasonic velocity drop is established.The study shows that the depth of dissolution is linearly proportional to the square root of the relative ultrasonic velocity drop,and the equivalent porosity and linear velocity drop increase linearly.The research results provide a reference for the application of ultrasonic nondestructive testing in concrete performance testing.