Research To Anti-sulfate Corrosion Resistance Of High Content Mineral Admixture Concrete

In recent years,high content mineral admixture concrete has been paid more and more attention because of its economical and environmental efficiency.With the addition of mineral admixtures,concrete is able to improve the anti-sulfate corrosion resistance,which is closely related to the fineness of mineral admixtures.Through putting into the mineral admixture,the interparticle gap is filled and then the internal pore structure of concrete is improved.Based on the point that mineral admixture can fill the interparticle gap with cement,two kinds of slag and fly ash with different fineness were used to achieve the optimization of particle matching,so as to prepare concrete with good anti-sulfate corrosion resistance.By analyzing the influence law of mineral admixtures on anti-sulfate corrosion resistance of concrete,summarized the optimal proportion.The main research object of this paper is high content mineral admixture concrete and the research content includes :(1)The effects on particle matching of cementitious materials with high content of mineral admixtures in different mixing methods,different total admixtures and different proportions of two mineral admixtures.(2)On the basis of particle matching and optimum design,prepared the concrete samples and evaluated the water-reducing performance and mechanical property of high content mineral admixture concrete.(3)Determination of sulfate corrosion degree under various blends mineral admixtures and comprehensive influence of sulfate corrosion to high content mineral admixture concrete.(4)Summarized and evaluated the optimal blend of high content mineral admixture concrete,and established the relation between the optimization of particle matching and anti-sulfate corrosion resistance of concrete.By the slurry fluidity test and sulfate corrosion test,the results show the following points.(1)The properties of cement slurry and concrete are mainly affected by fine mineral admixture when mixed with fly ash and slag with different fineness.(2)The improvement of particle matching by mineral admixtures does not only change the gradation of the particles,but also is closely related to the morphologyeffect of the mineral admixtures.By comparing two different ways of mixing S95 slag with fine fly ash,secondary fly ash with S115 slag,it is concluded that the former is better than the latter in terms of economical efficiency.(3)Concrete under optimization design of the cementitious material particle matching has good working performance,late mechanical performance and anti-sulfate corrosion resistance.(4)In terms of total content of mineral admixture,with the increase of total content of mineral admixture,the advantages of water reduction will be further expanded.The strength will increase first and then decrease,and the anti-sulfate corrosion resistance will reduce slightly.(5)In terms of mineral admixture and material admixture ratio,when blended with fine fly ash and S95 slag,the anti-sulfate corrosion resistance of concrete will be improved with the increase of slag content.At the same time,the capacity of reducing-water decreases slightly with the decrease of fly ash content.Based on the analysis of the reasons above and the conclusion of all levels,gived the optimal proportion scheme of cementitious materials for concrete with large amount of mineral admixture.Finally,the influence coefficient of the optimum mixture ratio and particle matching on the anti-sulfate corrosion resistance of concrete was quantified by building a mathematical model.