Experimental Study On Deterioration Law Of Pile Foundation Concrete Under Axial Compressive Loading In Sulfuric Acid Environment

The erosion of concrete by acid media is a complex reaction process.Most of the existing studies on the degradation law of concrete in acid environment do not consider the effect of load,which is inconsistent with the situation of concrete structure bearing load in actual engineering.Most of the current study was in carbonation,chloride ion,sulfate corrosion environment and load,under the action of the acid environment and load combination of the research(such as sulfuric acid,etc.)are lack of,if you ignore the influence of load,may cause the deviation of the test results bring potential safety hazard to engineering structures.In this paper,the durability of concrete specimens under the coupling action of sulfuric acid environment and axial compression load is studied.A charge device was designed to simulate the actual engineering of concrete specimen under pressure,in the p H = 0.85 dilute sulphuric acid environment of stress levels respectively 0 fc,0.15 fc,0.30 fc of ordinary concrete block on accelerated corrosion test,through the exterior appearance,durability evaluation index,the phenomenon of the chemical composition of the corrosion process observation records,etc.The main research contents include:(1)At home and abroad to consult the related documents,the existing environment and load coupling test method,this paper summarizes loading device,and combining the characteristics of the test requirements and all kinds of loading device,the related device design innovation,to create suitable for this topic of loading device,at the same time design conforms to the situation of the test plan;(2)By means of self-designed load-holding device,the compressive condition of concrete piles in actual engineering is simulated.By measuring the corrosion depth,mass loss,dynamic elastic modulus,dry water absorption rate of saturated surface and other mechanical properties and evaluation indexes,the macro damage phenomenon and mechanism of concrete piles under the coupling action of sulfuric acid environment and axial compression load are analyzed.(3)Using high precision 3D scanning apparent morphology of the specimens,through the data obtained,using MATLAB software according to the cube overlay method to calculate the fractal dimension of the specimen surface,the fractal dimension of fitting curve relationship with age,and relationship;By comparing the data of displacement sensor and strain gage in uniaxial compressive test,the accuracy of the technology in stress-strain test was verified.Meanwhile,relative strain data were obtained and stress-strain curves were drawn.(4)Using XRF(X-ray Fluorescence Spectrometry)equipment as an auxiliary means,from the aspect of chemical composition to study the concrete under the sulfuric acid environment-axial compression load coupling action of erosion mechanism,failure mode.