Study On Carbonization Resistance And Resistance To Chloride Ion Permeability Of Desert Sand Concrete

The main cause of concrete damage is corrosion of steel bars,which are caused by chlorine salt and carbonization.Sand is an indispensable part of concrete preparation,desert sand is mixed with sand instead of concrete,which is of great significance for reducing the cost,rationally utilizing new energy,and protecting the environment.This paper mainly studies the carbonation resistance and resistance to chloride ion permeability of desert sand concrete.The desert sand concrete with single fly ash,desert sand mixed with fly ash and desert sand was designed to analyze the effect of desert sand concrete on compressive strength,carbonation resistance,and chloride ion permeability.Four factors and three levels of orthogonal test were designed to analyze the effects of water binder ratio,fly ash dosage,sand ratio and desert sand replacement ratio on the compressive strength,carbonation resistance,and chloride ion permeability of desert sand concrete.The main research contents are as follows:1)The carbonation resistance test of concrete with single fly ash,single desert sand,and mixed fly ash and desert sand concrete was conducted.The influence of fly ash and desert sand on the carbonation performance of concrete was analyzed.The research shows that:in single fly ash concrete,the content of fly ash increases from 0-30%,the depth of carbonation increases,and the carbonation resistance of fly ash concrete decreases.For single desert sand concrete,the desert sand content increased from 0-80%,and the carbonation depth of desert sand concrete first decreased and then increased.That is to say,desert sand concrete had the smallest carbonization depth and was resistant to carbonization when the desert sand content was 20%.Optimal performance;The age of carbonation increased from 3d to 56d,and the carbonation depth of the mixed admixture concrete increased continuously.When the desertification sand concrete had the smallest carbonization depth,the fly ash content was 10%,and the replacement rate of desert sand was 20%.A prediction model for the carbonation depth of concrete with 28d mixed admixture was established.2)Orthogonal test was designed to test the carbonization resistance performance of desert sand concrete of 3d,7d,14d,28d,56d with water binder ratio,fly ash dosage,sand ratio and desert sand replacement ratio.The effects of four factors on the carbonization resistance of desert sand concrete are analyzed.Research shows:with the increasing of the age of carbonization,the carbonization depth increases,and the carbonization resistance performance of desert sand concrete is reduced.the influence of various factors on the carbonation resistance of desert sand concrete at carbonization age 3d is that fly ash dosage is the strongest,water-binder ratio is second,sand ratio is third and desert sand replacement ratio is the weakest.The influence of various factors on the carbonation resistance of desert sand concrete at carbonization age 7 d and 14d is that fly ash dosage is the strongest,water-binder ratio is second,desert sand replacement ratio is third and sand ratio is the weakest.The influence of various factors on the carbonation resistance of desert sand concrete at carbonization age 28 d and 56 d is that water-binder ratio is the strongest,fly ash dosage is second,desert sand replacement ratio is third and sand ratio is the weakest.3)Experiments on resistance to chloride ion permeability of single fly ash,single desert sand,mixture of fly ash and desert sand concrete were carried out.The influence of fly ash and desert sand on resistance to chloride ion permeability of concrete was analyzed.Research shows:for single fly ash concrete,with the increase of fly ash content,enhance the chloride resistance of concrete;for single desert sand concrete,with the increase of desert sand replacement rate,the performance of concrete resistance to chloride ion was first increased and then decreased trend,the best performance of concrete resistance to chloride ion of desert sand replacement rate is 60%;for fly ash and desert sand concrete,fly ash 30%,desert sand replacement rate of 60%when the resistance of concrete to chloride the best performance of ion.4)Orthogonal test was designed to chloride ion permeability performance of desert sand concrete with water binder ratio,fly ash dosage,sand ratio and desert sand replacement ratio.The effects of four factors on the chloride ion permeability performance of desert sand concrete are analyzed.Research shows:The importance of the influence of fly ash dosage on the 28d electric flux of desert sand concrete is first.Water binder ratio is second.Sand ratio and desert sand replacement ratio are third and last,with the increase of the concentration of sodium chloride,the electrical capacity of sand concrete in desert sand increases.