Research On The Performance Of Resistance To Chloride Ion Erosion Of The Concrete With High Volume Mineral Admixtures

Chloride erosion is the main cause of the durability damage of the concrete structure in chloride environment.Currently,mineral admixtures are gradually used in the preparation of concrete because of its environmental friendlinss and pozzolanic activity,which can reduce the environmental burden and improve the durability of concrete.Meanwhile,mineral admixtures have been also widely used in the engineering structures under chloride environment such as seaport wharf,cross-sea bridges and so on.In this paper,the high volume mineral admixtures concrete(total content of the mineral admixtures is from 50%to 70%,both of the fly ash and slag content are from 15%to 55%)was studied.The concrete compressive strength test,6h electric flux test and rapid chloride migration test were carried out at the same time.Besides,the mechanical properties and the resistance to chloride ion erosion of the high volume mineral admixtures concrete were analyzed,which can establish the multi-factor models for the anti-chlorine erosion performance of high volume mineral admixtures concrete.The main research contents and conclusions of this paper are shown as follows:1.Based on the test methods of orthogonal design and full range design,15 groups of high volume mineral admixtures concrete were prepared.The compressive strength,6h electric flux and chloride diffusion coefficient of the concrete were tested to analyze the influence of the water-binder ratio,fly ash content,slag content and mineral admixtures' combination on the compressive strength in 28d and the anti-chlorine erosion performance both of 28d and 56d.It has been proved in the research that with the increase of water-binder ratio,compressive strength of the high volume mineral admixtures concrete in 28d decreases.With the fly ash content and slag content increasd,the compressive strength would also reduced.And under the same total content of mineral admixtures and water-binder ratio,the compressive strength of 28d decreases with the increasing fly ash content.Furthermore,with the increase of the total content of mineral admixtures(from 50%to 70%),the performance of resistance to chloride ion erosion has been improved.When the total content is constant,the concrete whose fly ash and slag has the same content possess the best performance of resistance to chloride ion erosion.2.According to the statistical analysis,the correlation between the chloride diffusion coefficient and the electric flux of the high volume mineral admixtures concrete was studied.The result has indicated that there is a good linear relationship between the 6h electric flux and the chloride diffusion coefficient.Besides,the performance of resistance to chloride ion erosion of the high volume mineral admixtures concrete for the age of 28d and 56d also has a linear correlation.3.Range analysis and variance analysis for the compressive strength and the anti-chlorine erosion test results of the 9 groups concrete which are based on the orthogonal design have been studied.The results show that the influence of the priority and the significant degree on the compressive strength and the resistance to chloride ion erosion follows the order:water-binder ratio>total content of mineral admixtures>content ratio of fly ash and slag.4.Based on the least square method and the 9 groups of orthogonal experimental datas,the multi-factor models of the electric flux and the chloride diffusion coefficient for the high volume mineral admixtures concrete were established.In addition,the significance test and correlation analysis have been used to prove a high goodness of fit between the prediction models and the experimental datas.Furthermore,comparing the measured value of electric flux and chloride diffusion coefficient of the other 6 groups concrete with the model predicted vaule,it has turned out that the multi-factor models is accurate and reasonable.Compared with the linear model,the established multi-factor coupled model has a higher goodness of fit and can reflect the relationship between the chloride ion corrosion and the factors better.