Rutting Resistance of Asphalt Overlay with Multilayer Wheel Tracking Test

The rutting resistance of maltilayer asphalt overlay was researched by using laboratoty wheel tracking test. The effects of loading level and test temperature on rutting resistance of asphalt overlay structure were evahuaed by means of multilayer specimens . In comparison with multilayer tests, standard specimens of various layers were also conducted to evaluate the rutting resistance. Experimental results indicated that the test tempercature and applied load have a significant effect on rutting resistance of asphalt concrete. Higher test tempercature and heavier applied load resulted in higher rut depths. In addition, the mutilayer wheel tracking test has been demonstrated to be a more reasonable solution in evaluation on rutting resistance of asphatt pavement structure beasuse it reflects the cumulative permanent deformation in all of asphalt layers.

Rheological Evaluation of Polymer Modified Asphalt Binders

The microstructure and dynamic rheological characteristics of asphalt containing different polymer modifiers （crumb rubber, styrene-butadiene-styrene and crumb rubber mix with styrene- butadiene-styrene） at mid and high service temperature levels were investigated by using scanning electron microscopy（SEM）, dynamic shear rheometer（DSR） and repeat creep test. The main objective of the investigation was to rank the modifiers based on their effect on performance characteristics of asphalt under service conditions. To evaluate the effect of different modifiers on the viscoelastic response of asphalt, the temperature and frequency dependences of the dynamic viscoelastic properties were compared. The mid-temperature fatigue resistance and high-temperature rutting resistance of three polymer modified asphalts were evaluated to predict their field performance in roads. Based on the current results, an improved rutting factor was proposed to determine the rutting resistance of asphalt pavements. In addition, the viscous stiffness （Gv）, defined as the reciprocal of viscous compliance, was used to evaluate the high-temperature deformation resistance of asphalt mixtures. The experimental results indicate that the asphalt containing crumb rubber only shows superior performance at mid and high service temperatures in all three modified asphalt binders due to the action of the crumb rubber.

Anti-rutting performance evaluation of modified asphalt binders: A review

Asphalt pavement inevitably suffers rutting distress induced by repeated loads under high temperatures, which can be effectively alleviated by the modification of asphalt binders.This paper summarized the asphalt modifiers for enhancing the performance of asphalt pavement at high temperatures in terms of the modifier type, additive amount and improving effect. Then, the anti-rutting performance evaluation methods of asphalt binder were introduced with details, including the ring and ball(R&B) test, the dynamic viscosity test, the zero/low shear viscosity(ZSV/LSV) test, the dynamic shear rheometer(DSR) test,the repeated creep and recovery(RCR) test, and the multiple stress creep and recovery(MSCR) test. Furthermore, the sensitivity of the evaluation method to asphalt modifier was analyzed using the normalization method. It was found that the indicators from the MSCR test could clearly reveal the influence of asphalt modifiers on high temperature performance of asphalt binder. But it still had some limitations affecting the accuracy of evaluation results, such as the number of creep-recovery cycles, the stress level and the recovery time. In addition, according to the rutting resistance improvement ratio(RRIR),the styrene-butadiene-styrene(SBS) modifier performed better in improving the rutting resistance of asphalt binder, compared with other modifiers when added within the usual dosage range.

Evaluation of fatigue and rutting properties of asphalt binderand mastic modified by synthesized polyurethane

Fatigue and rutting phenomena are major distresses in asphalt pavements.Asphalt mixture properties are highly dependent upon the asphalt binder and the mastic behavior.The purpose of this study was to investigate the behavior of the asphalt binder and the mastic,modified by the synthesized polyurethane,at high and intermediate temperatures.The filler/asphalt binder ratio(by weight)was 1.0.The dynamic shear rheometer(DSR)was used to measure fatigue(G^(*)sinδ)and rutting(G^(*)/sinδ)parameters.In this study,the multiple stress creepandrecovery(MSCR)testwasalso utilizedto calculate the ruttingpotential of theasphalt binder and themastic.Parameters of the non-recoverable compliance(Jnr)and the percentage recovery(%)were evaluated at high temperatures.The obtained results indicated that the synthesizedpolyurethaneimproved the ruttingandfatigue properties.Therewasa significant correlation between the asphalt binder and the mastic in terms of the complex modulus(R^(2)=0.9958),rutting(R^(2)=0.9944),and the non-recoverable compliance(R^(2)=0.9707).For the fatigue parameter(R^(2)=0.9852),the complex modulus(R^(2)=0.9855),and the phase angle(R^(2)=0.8262),significant relationships were observed between the asphalt binder and mastic samples at intermediate temperatures.Overall,the chemical reaction between the filler and the asphalt binder could be effective in different behaviors of the mastic and asphalt binder.Therewasa 112%-164%increase in the G^(*)sinδparameter formastics,compared to that of the asphalt binder.The complex modulus was 6 times higher by adding the filler content.

Effect of Active Mineral Filler on Rutting Performance and Fatigue Properties of Granite Asphalt Concrete

Granite is well known as an acid aggregate. An active mineral filler produced in the laboratory is first used as an anti-stripping filler in the granite asphalt concrete. Four aggregate gradations were chosen in this study,and the effects of the active mineral filler and aggregates on the rutting resistance performance and fatigue properties of granite asphalt concrete were investigated by means of rutting test and four-point bending fatigue test. The results indicate that the dynamic stability of granite asphalt concrete increase significantly with the addition of active mineral filler and the fatigue properties can also be improved especially at lower strain level. Meanwhile,the results demonstrate that granite asphalt concrete has better rutting resistance performance and fatigue properties than limestone asphalt concrete.

Development of high stability hot mix asphalt concrete with hybrid binder

Cost reduction of public works projects has been desired due to severe financial circumstances. Therefore, asphalt pavement has been requested to extend its life. Semi-flexible pavement or epoxy asphalt pavement, which has high rutting resistance and oil resistance, may be applied to the place where these performances are demanded. However, special technique is required in manufacturing and construction. In addition, these materials have also raised a problem that they cannot be recycled. Meanwhile, conventional asphalt pavement has several drawbacks. It is vulnerable to rutting caused by traffic load and damage caused by petroleum oils such as gasoline or motor oil. The materials used in asphalt mixtures were studied for improving the durability of asphalt mixture. A high stability asphalt concrete was developed which has equal or superior performance to semi-flexible pavement and epoxy asphalt pavement. In this paper, the process of selecting the substance and the characteristics evaluation of the developed mixtures are described. Furthermore, an inspection result as well as follow- up survey of the performance of the developed mixtures obtained from trial and actual construction is shown.