Experimental Research On Alkali-activated Slag Concrete With Recycled Aggregate

Slag is a by-product of metallurgical industry,which has a large amount of emissions in China,and the application of it is still very limited.Nowadays slag is mainly use for producing slag cement or being a admixture in concrete in our country.Some researches have found that it was a environmental friendly material,which has excellent performance and the consumption of it was less than other material,by using alkali-activated the activity of slag.With the acceleration of urbanization in China,there are much solid waste has been accumulated,most of which was wasted concrete.And then more and more researches are made on the production of recycled aggregate concrete.The combination of alkali-activated slag cement and recycled aggregate is a new idea,which is still in a blank in our country.The study of this new material have great significance to the sustainable development strategy of saving resources and protecting environment.The topic have done some experiments in alkali-activated slag concrete with recycled aggregate,which used the slag produced by Yunnan Kunming Jiahua cement co.,Ltd.The experiment was designed to a orthogonal experiment,and utilized the methods of range analysis and variance analysis to analysis the degree of the effect on the performance of alkali-activated cement like setting time,fluidity and strength of mortar by adjusting three major factors included the modulus of water glass,concentration of alkali solution,and ratio of solution and slag’s quality,and found a better proportion(the modulus of water glass was 1.0,the concentration of alkali solution was 6%,and ratio of solution and slag’s quality was 0.55)of alkali-activated cement,used the SEM(scanning electron microscope)to analysis the hydration product of alkali-activated cement with better proportion.On the basis of previous experiments,used the alkali-activated slag cement which was prepared to manufacture alkali-activated slag concrete with recycled aggregate,and analysis the impact law of the working performance,drying shrinkage,compressive strength and elastic modulus of alkali-activated slag concrete with recycled aggregate,by adjusting substitution rate of recycled aggregate(0,20%,40%,60%,80%,100%)and two different methods of mixing additional water(once added,twice added).When the admixtures of recycled aggregate lower than 60%,the addition of recycled aggregate has little effect on the working performance,drying shrinkage,compressive strength,elastic modulus of alkali-activated slag concrete with recycled aggregate.This research,not only found a new way to popularize and apply the ground granulated blast furnace slag,and also laid a foundation to the application of alkali-activated slag concrete with recycled aggregate in engineering.