Research On The Hot-bonding Technique In Waterproof Of Asphalt Concrete Bridge Deck

Rational treatment of the bridge deck surface before the waterproof adhesivelayer construction can improve the bonding properties of the bridge deck pavementthat plays an important role to improve bridge durability.The existing highwayasphalt pavement design specifications only have a vague description to deal withthe bridge deck surface, and not yet to develop appropriate evaluation criteria, thebridge deck surface treatment problems are urgently to be solved. Combination oftheoretical analysis and experimental verification to explore the laws of the bridgedeck surface moisture content and temperature on the performance of thewaterproof adhesive layer, at last put forward the method of hot-bonding betweenasphalt concrete and cement concrete bridge deck.In order to analysis the adhesion between asphalt and grass-roots concrete,surface energy theory was used to obtain parameters of SBS asphalt andgrass-roots concrete under difference moisture content by the column wickingtechnique and Sessile drop method. Sessile drop method was used to measurecontact angle between cement concrete and SBS asphalt under the circumstancesof different temperatures, and then the adhesion work was calculated. The resultsindicate that with moisture content’s decrease, the pullout test performance ofwaterproof adhesive layer on bridge deck is enhanced, but when moisture contentin the [0%,0.5%] range, the adhesion work on the moisture content is not sensitive;with the rise of concrete temperature, the adhesion work increases.On the basis of surface energy theory, the bonding properties between cementconcrete and SBS asphalt were verified at different temperatures and differentmoisture content. With moisture content’s decrease, the pullout test performanceof waterproof adhesive layer on bridge deck is enhanced, when the moisturecontent was0.5%, interlamination adhesive performance of bridge deck hit thebest condition of SBS hot asphalt. With temperature’s increase and moisturecontent’s decrease, the shear strength of waterproof adhesive layer on bridge deckis also enhanced, but it is not obvious after moisture content is under1.0%. As theconcrete temperature increases, the bonding properties of the waterproof layerimproves, but when the temperature hits to60℃, the bonding properties betweenlayers are not sensitive to temperature; as the concrete temperature increases,waterproof layer anti-shear property has been improved, but when the temperaturehits to50℃, the magnitude of improvement decreases.To sum up, the bridge deck surface moisture content and temperature on thewaterproof adhesive layer properties have a certain influence, the law obtained by the two analysis methods of conventional test and surface energy theory had aexcellent consistency.Because of the theoretical analysis ignores the impact of Thebridge deck surface roughness and the combined effect of temperature andhumidity,so a single evaluation method had certain limitations, proposedcombination of the two methods to the evaluation of the bridge deck surfaceproperties of waterproof adhesive layer performance impact. Experimental andtheoretical analysis showed that, before construction of SBS modified bitumenadhesive layer, heat the bridge deck to reduce the surface moisture and improvetemperature of deck, to achieve thermal bridge deck waterproofing adhesive layerbonding process, that can improve the bonding properties between waterproofadhesive layer and concrete bridge deck to improve the performance and durabilityof the bridge deck pavement.