Experimental Study On Concrete Of Newly Discharged Steel Slag Aggregate Pavement

The rapid development of Chinese steel industry,the increase of steel slag emissions and low utilization rate,a large number of new exhaust steel slag often need to occupy a piece of land aging to the relatively stable slag will be used.Aging or stacking will cause serious pollution to the ecological environment.Moreover,cement concrete pavement still occupies a large proportion in Chinese pavement structure.As a coarse aggregate of traditional mixed cement concrete pavement,gravel has caused great damage to the environment due to its over exploitation.Based on the above two realities,this thesis adheres to the idea of turning waste into treasure.With steel slag coarse aggregate pavement concrete and mineral material steel slag coarse aggregate pavement concrete stability as the premise,the mechanical properties and frost resistance of steel slag pavement concrete are studied,and the microstructure of the interface transition zone and the morphology of hydration products are analyzed using scanning electron microscope.According to the test,the following five conclusions are mainly drawn:1.Prepare steel slag pavement concrete by only mixed with new discharge steel slag coarse aggregate instead of gravel,and the maximum mixing amount meeting the stability requirements is 30%.2.Reasonable admixture of silica ash and fly ash can improve the stability of pavement concrete with a new mixing amount of coarse aggregate of 50%.Under the mixing amount of 10%silica ash,25%fly ash and 15%silica ash,the test block is pressed and steamed and intact,and the corresponding compressive strength retention rate after boiling is 97.9%,96.0%and 95.2%,respectively.It is judged that 10%silica ash has the best improvement effect,followed by 20%fly ash,and 15%silica ash.3.Mixed mineral materials（silica ash,fly ash）can improve the strength of steel slag coarse aggregate pavement concrete.At 28d of age,The mechanical performance of 10%silicon ash on the coarse aggregate pavement concrete is optimal.The compressive strength and tensile strength are higher by 17.3%and 15.5%respectively,and the tensile strength of steel slag pavement concrete mixed with 25%fly ash is not different from 15%when not mixed.4.In the case of single steel slag,the best frost resistance of the coarse aggregate of steel slag is 30%.When the amount of steel slag coarse aggregate mixing is 50%,150times,25%fly ash,10%silicon ash,15%silicon ash,5.8%,5.6%,7.8%respectively,and10%fly ash,50%steel slag coarse aggregate pavement concrete frost improvement effect is similar,which is better than that of 15%silicon ash.5.The incorporation of steel slag optimizes the concrete interface structure,and the degree of binding between the substrate is closer.The incorporation of silica ash and fly ash produces more hydration product C-S-H gel,which improves the performance of steel slag pavement concrete.The improvement effect of silica ash with high Si O₂ content is better than the fly ash.