Research On Waterproof-bonding Layer Of Cement Concrete Pavement

The performance of cement concrete pavement under repeated loading ofexternal environment and vehicles load is getting worse year by year, and appears avariety of types of damage. The nature of damage can be divided into functionaldamage and structural damage. The imperfect contact between the cement concretepavement and the base layer, poor ability of erosion resistance of the semi-rigid basehave become main reasons for the pavement surface damage. Through the analysis ofthe traditional pavement structure, a pavement structure that set a waterproof-bondinglayer between cement concrete pavement and semi-rigid base was proposed. Thispaper analyzed the effect of different modulus and thickness of waterproof-bondinglayer under load and temperature on the concrete slab stress. Thereby the appropriatethickness of context layer is2cm and the threshold value of modulus is1000MPa.At present, synthetic fibers, modified asphalt and other materials are usuallyused to improve the high temperature stability of bituminous concrete, while usingcement substitute slag powder for reducing the water damage of asphalt mixture. It isknown that the waterproof-bonding layer of hot mix asphalt using modified bitumenor synthetic fibers to improve its high temperature stability is very expensive, and theusing of cement is not very effective and environmentally friendly. Research showsthat steel slag powder replacing slag powder can improve the water stability and hightemperatures stability of asphalt mixture which can reduce the consumption ofresources and is environment friendly. In this paper, the laboratory test about sand-size asphalt mixture layer with the steel slag powder was carried out, and the effectof total or partial replacement of mineral powder with steel slag powder onperformance of asphalt mixture was studied. By Marshall stability test, the influenceof different quantity mixes of steel slag powder on the asphalt concrete hightemperature stability was evaluated, and by freezing and thawing splitting test, theinfluence of different quantity mixes of steel slag powder on the bituminous mixturewater stability was evaluated, respectively. By three indicators trials of asphalt masticand asphalt mixture, the results indicated that water stability and high temperaturestability of asphalt mixture can be improved markedly when the steel slag powderwas used to substitute mineral powder. And the influence of the steel slag powderaddition on the anti-cracking performance of asphalt mixture was little. In this paper, the optimum asphalt content of asphalt mixture in accordance with the relevant testand calculation is7.5%. The most optimum dosage of steel slag powder in aggregateis6%. The improvement of bituminous mixture performance mechanism lied in thesteel slag alkalinity and the relative surface accumulates in a certain way. This paperstudied the various properties of asphalt concrete mixed with steel slag powder as thewaterproof-bonding layer.