Study On The Rheological Properties Of Instant High Viscosity Asphalt Used For Deck Pavement Of Large Steel Concrete Composite Beam Bridges

Large steel concrete composite beam bridges are a common structural form in the construction of transportation infrastructure such as highways and railways.Their bearing capacity and service life are important factors in ensuring traffic safety and economic benefits.As the pavement material for large-scale steel-concrete composite beam bridges,asphalt mixture has attracted widespread attention due to its excellent performance and application.In practical use,the adhesion,stability,and durability of asphalt mixtures are crucial for ensuring the long-term safe use of the bridge.Traditional asphalt mixtures require heating and extended waiting periods during construction before the asphalt binder achieves the necessary adhesion and flowability.This construction method has many problems,such as low efficiency,high time costs,and environmental pollution.Therefore,developing a soluble and high-viscosity asphalt is an effective way to solve these problems.However,there is still relatively little research on the rheological properties of soluble and high-viscosity asphalt used for engineering applications,and further research and exploration are needed to meet the requirements of steel-concrete composite beam bridge pavement and improve pavement quality and service life.Therefore,this thesis aims to study the rheological properties of soluble and high-viscosity asphalt used for pavement on large-scale steel-concrete composite beam bridges,in order to improve pavement quality and service life,and to provide support and guarantee for the construction of transportation infrastructure such as highways.In response to the above-mentioned issues,this thesis used self-made fast-dissolving high-viscosity modifiers with little difference in molecular weight,and adopted a given preparation process for preparing modified asphalt.Two dosages were designed for the pavement layer,and one dosage was designed for the bonding layer.Firstly,based on the penetration grade and the Superpave performance grade(PG)system,a comparison with SBS modified asphalt was made to evaluate the high and low temperature performance of the instant high viscosity asphalt.Then,microscopic performance tests were carried out on the instant high viscosity asphalt to observe and analyze the distribution of modifiers and functional groups,and the effect of modifier dosage and molecular weight changes on the surface characteristics and aging degree of asphalt.The above-mentioned research has found that instantaneously soluble high-viscosity modified asphalt exhibits superior high and lowtemperature performance compared to SBS-modified asphalt.Furthermore,increasing the dosage and molecular weight of the modifier can optimize the high and low-temperature performance as well as the anti-aging properties of instantaneously soluble high-viscosity modified asphalt.Additionally,the instantaneously soluble high-viscosity modifier can be uniformly dispersed and fully swollen in the base asphalt,and the preparation process of instantaneously soluble high-viscosity modified asphalt involves physical and chemical blending.The main rheological tests in this article are conducted on the instant high viscosity asphalt,including rotational viscosity tests,temperature scanning tests,MSCR tests,frequency scanning tests,and time scanning tests,which are compared with SBS-modified asphalt to obtain corresponding trends and regularities.The rotational viscosity test is used to analyze the Brookfield viscosity and plot the viscosity-temperature curve to observe the changes in viscosity with temperature,modifier content,and molecular weight.The research findings indicate that instantaneously soluble high-viscosity asphalt outperforms SBS-modified asphalt in terms of both viscosity and temperature sensitivity.Moreover,increasing the dosage and molecular weight of the modifier can optimize the viscosity and temperature sensitivity of instantaneously soluble high-viscosity asphalt.The temperature scanning test is used to analyze the changes in δ,tanδ,G*,and G*/sinδ of high-viscosity quick-setting asphalt with temperature,modifier content,and molecular weight.The research indicates that the aforementioned indicators of instantaneously soluble high-viscosity asphalt are higher than those of SBS-modified asphalt.Furthermore,as the dosage of the modifier increases and the molecular weight becomes larger,the modified asphalt exhibits greater resistance to rutting.The MSCR test is used to analyze the elastic recovery ability of modified high-viscosity quick-setting asphalt under light and heavy loads with changes in temperature,modifier content,and molecular weight.The research shows that the elastic recovery capability of modified asphalt is compromised after aging.However,with an increase in the dosage and molecular weight of the modifier,the corresponding modified asphalt exhibits an enhanced elastic recovery capability and resistance to permanent deformation to some extent.The main curve obtained from the frequency scanning test is used to analyze the anti-aging performance of the modified high-viscosity quick-setting asphalt.The research findings indicate that higher dosage and molecular weight of the modifier result in a higher proportion of asphalt viscosity after PAV pressure aging,making the asphalt softer and exhibiting less severe aging.This demonstrates a stronger anti-aging ability.The time scanning test is used to analyze the fatigue life and anti-aging performance of modified asphalt with changes in modifier content and molecular weight.The research indicates that with the increase in dosage and molecular weight of the modifier,the fatigue life of asphalt and its resistance to aging gradually improve.The comprehensive designed experiments indicate that the instant high viscosity asphalt can improve the high and low temperature performance,fatigue resistance performance,and anti-aging performance of the asphalt,and optimize the two dosages in the paving layer.For the bonding layer,this article uses a shear-pull test to compare data from five designed application rates and selects the optimal application rate.