Experimental Study On Durability And Mechanical Properties Of All-light Shale Ceramsite Concrete

Light shale ceramsite concrete is made of shale ceramsite and ceramsite sand as aggregate instead of pebble and river sand in ordinary concrete,so it has light texture and good thermal insulation performance.This paper mainly studies and analyzes the basic mechanical properties and durability of all-light shale ceramsite concrete.The main research contents and innovations are as follows:(1)On the basis of previous studies,a large number of trials are made,and the lightweight shale ceramsite concrete with strength grade of LC20～LC45 is prepared.The basic mechanical properties such as axial compressive strength,cubic compressive strength,elastic modulus and splitting tensile strength are measured.Compared with ordinary concrete,the advantages and engineering application prospects of lightweight shale ceramsite concrete are analyzed.(2)The rapid carbonation test of specimens with four strength grades of LC20-LC45 was carried out.Combined with the test situation and the existing academic research results,the carbonation mechanism and carbonation resistance of all-light shale ceramsite concrete were analyzed,and the carbonation depth prediction model of all-light shale concrete considering the standard value of cube compressive strength and carbonation time was obtained.(3)200 freeze-thaw cycles were carried out on specimens with four strength grades of LC20-LC45,and the test phenomena in the process of freeze-thaw cycles were analyzed.The mass loss rate,dynamic elastic modulus loss rate and compressive strength loss rate of specimens after 200 freeze-thaw cycles were tested.Based on the change value of relative dynamic elastic modulus,the prediction model of relative dynamic elastic modulus of all-light shale ceramsite concrete was proposed,and the life assessment of all-light shale ceramsite concrete structure in northern China was carried out.(4)The resistance to chloride ion penetration of all-light shale ceramsite concrete was studied through the chloride ion penetration test and electrochemical accelerated corrosion test on the specimens with four strength grades of LC20～LC45,and the results were compared with those of ordinary concrete.The influence of concrete strength grade and steel bar diameter on the corrosion rate of steel bars in concrete structures is studied,and the corrosion characteristics of shale ceramsite concrete specimens are analyzed.The influence of concrete strength grade and steel bar diameter on the corrosion rate of steel bars in concrete structures is obtained.Through LC30 plain concrete corrosion test,the calculation model of cube compressive strength of all-light shale ceramsite concrete corroded by chloride salt was proposed.