Research On The Structure And Material Composition Of Color Composite Cement Concrete Pavement

With the rapid development of China’s transportation industry,colored cement concrete pavement has now been widely used in ETC lanes,high-speed service areas and other specific highway sections.In this paper,with the characteristics of composite pavement into layers,only the upper layer is designed as colored pavement,and the lower layer is still ordinary concrete pavement.Compared with traditional colored concrete pavement,the upper layer of colored pavement and the lower layer of ordinary concrete pavement jointly bear the vehicle load.On the one hand: the amount of colored concrete is less,which reduces the project cost;on the other hand: it can give full play to the respective advantages of different strength pavements,reduce pavement diseases,and improve the strength and service life of cement concrete pavements.For the current problems of low strength and dull color of colored concrete pavement,this paper proposes to use three kinds of stains,such as silver pearl red,ultramarine blue and fine art green,instead of the traditional iron oxide series of stains through a series of tests such as color durability test,mechanical performance test and frost resistance test.The color parameters of the specimens were collected using a color difference meter,which proved that the new stains were generally better than the traditional stains,and the color recession curve was drawn,and it was found that among the three colors,the fading of the red specimens was the most serious,followed by blue,and green was the lightest.Through the compressive and flexural tests,it was proved that the specimens with ultramarine blue and art green stains were better than traditional iron oxide stains in terms of mechanical properties,and it was determined that 6% of ultramarine blue and 4% of art green were the best dose of the stain,and its frost resistance was studied.There are few studies on composite concrete pavements and lack of research on the effect of structural form changes on layer bottom stress.In this paper,the effects of structural combination form,surface layer thickness and interlayer contact conditions of composite concrete pavement on layer bottom load stress and temperature stress are studied,and it is found that the effect of the change of the strength or thickness of the layer below is more obvious for the layer bottom stress compared with the change of the strength or thickness of the layer above;when the interlayer friction coefficient increases,the layer bottom stress of different structures all decrease with it,and the magnitude of the decrease is similar,for For temperature stress and coupling stress,the decrease of stress is inversely proportional to the thickness of the surface layer.In order to meet the requirements of composite concrete pavement under heavy traffic,two kinds of pavement structures,"poor concrete base layer + composite concrete surface layer" or "water-stabilized gravel base layer + reinforced concrete surface layer",are designed,and through the analysis of the mechanical response of the pavement structure,it is found that When the modulus of the poor concrete is larger,the load stress at the bottom of the layer is smaller,but the temperature stress does not change significantly;when the reinforcement mesh is located at 1/3-1/2 of the surface layer thickness and near 1/3,the stress at the bottom of the layer is the smallest.According to the load stress and temperature stress calculated by the finite element software,combined with the formula of fatigue stress and ultimate stress in the specification,the type of pavement structure under different traffic load levels is recommended.