Study On The Effect Of Steel Slag Powder On The Performance Of Road Concrete

With the rapid development of cement concrete pavement, cement concrete pavement, as a main form of pavement structure, occupies a large proportion in our country. However, various problems, including raw materials, construction level, external environment and vehicle load factors, result in variety of diseases of cement concrete pavement within it use period, and prominent road concrete durability deterioration problem. At the same time, a large number of industrial emissions of steel slag and other industrial waste were produced every year, and occupy a lot of land, and pile up like a mountain hand, which causes serious environmental pollution, destruction of ecological resources. In this paper, steel slag and other industrial wastes were adopted as the road concrete admixtures for improving the quality and service life of cement concrete pavement, and making full use of industrial waste resources. This thesis has a good social and economic benefits and positive significance for promoting the development of the cement concrete pavement, which was in accordance with the national themes of energy-saving emission reduction and sustainable development.Firstly, this thesis studed the gelation of Laiwu steel slag powder and Rizhao steel slag powder, and compared the activity of these two kinds of steel slag. Then we prepared cement based composite cementitious materials through replacing cement with the similar amount of the single mixed steel slag powder, composite mixed steel slag powder and slag powder, and the composite mixed fly ash, steel slag powder and slag powder. Finally, this thesis studies the standard consistency, setting time, fluidity and stability of composite binding material, as well as standard 3d, 7d, 28 d, 90 d mortar flexural-compressive strength. The optimal dosage of composite cementitious materials and mixture ratio was 30% of the composite powder and 70% of cement, and the composite powder was composed by equal mass of Laiwu Steel slag powder, slag powder, fly ash.On the basis of the abovementioned investigation, we designed road concrete mixture ratio for the application in the severe traffic grade and medium grade traffic. Effect of the mass admixture ratio of the composed Laiwu steel slag powder, slag powder and fly ash on the performance of concrete pavement, including work performance of road concrete, mechanical properties and durability(wear resistance, frost resistance, volume stability), were investigated,. The test results show that the composite powder significantly increase the the road performance of the composed concrete under different traffic grade, and thus extend the life of concrete road, indicating the better social and economic benefits of this study.In addition, this thesis used 3D heat of hydration, differential thermal thermal gravimetric analysis, X-ray diffraction analysis, SEM analysis, microscopic pore structure analysis and other testing methods for the comprehensive analysis of the effect of steel slag powder, slag powder and fly ash on hydration mechanism of cement-based composite cementitious materials.