Study On The Carbonation Resistance Of High Performance Concrete With Rompound Admixtures

In recent years, serious damages of buildings often occur because of carbonation ofconcrete. The carbonation of concrete as an important part of the concrete durability researchhas drawn more and more attention. Researching the law of concrete Carbonation has importanttheoretical and practicalsignificance to improve durability of reinforced concrete structures.Thisarticle created High-performance concretes by replacing part of the cement with a complexadmixture made from super-fine steel slag powder, fly ash, mineral powder and wollastonitepowder. Based on experiment and the analysis for carbonization of the High performanceconcrete.This article researched on various factors and microstucture of its carbonization, andhave reached an proportion plan for concrete which has carbonation resistance requirements.The main conclusions are as following:(1) When mixing single species admixture, the influence of the quantity and replacementtype on the carbonation of High performance concrete has been researched, the result showsthat the carbonation resistance of concrete mixed with mineral admixture is lower than thereference concrete, the carbonation resistance of concrete mixed with wollastonite powder isbetter than the concrete mixed with other admixtures.(2) The steel slag and wollastonite powder admixtures make concrete carbonationresistance improved, the High performance concrete which adoped0.35water binder ratio and20%replacement has good carbonation resistance.(3) The concrete carbonation resistance of three ternary compound admixtures is moreimproved. The combination of super-fine steel slag, fly ash and wollastonite combination is thebest; super-fine steel slag powder, fly ash and mineral powder comes second; super-fine steelslag powder, mineral powder and the wollastonite combination is the worst.(4)Adding the hydrated lime plays a significant role to reduce the depth of concretecarbonation14days ago, concrete carbonation depth decreases with increasing the amount ofhydrated lime.(5) The mercury pressure test shows that water binder ratio is the major factor of porestructure. It can make full use of its micro aggregate filling effect by adding mineral admixturesso as to increase the compaction of the concrete structure. Three ternary compound admixturesconcrete structure is better than benchmark concrete.