Interlayer Adhesive Materials And Anti-shearing Performance Of Asphalt Pavement On Steep Slope Sections In Seasonal Frozen Soil Region

The construction of asphalt pavement on highways'steep slope sections has faced enormous challenges under the influence of comprehensive factors,such as topography,landform,and climate in seasonal frozen soil region.The degradation in asphalt pavement's asphalt binder and anti-shearing performance on steep slope sections have caused many urgent problems as cutting,slippage,folding,and U-shaped cracking.In this study,the variation in the dynamic viscoelastic shear parameters depending on the number of freeze-thaw cycles was investigated through DSR test on the asphalt binders after multiple freeze-thaw cycles,and the theoretical model for an asphalt mixture's dynamic modulus prediction considering bonded materials'dynamic viscoelastic shear parameters was established.The FTIR spectra of different brands of asphalt binders with different aging cycles were calculated quantitatively,and a reliable FTIR quantification analytical method was proposed.Based on the mathematical model of grey relational entropy analysis,the influence of different functional group content changes on the pavement performance of asphalt binders was discussed.The prediction equation of complex shear modulus was predicted by the characteristic functional group content.Mechanics calculation,software programme exploitation,and laboratory tests were combined to study the interlayer adhesive materials and anti-shearing performance of asphalt pavement,and the characteristics of the interlayer stress-strain change of asphalt pavement structures under different interlayer contact conditions were analyzed.Based on the shear fatigue life prediction equation under different shear stress levels,the interlayer shear fatigue life prediction equation considering freeze-thaw cycles was established.The results can provide the theoretical basis and technical support for asphalt pavement material selection and structural design on steep slope sections.The conclusions of the study are as follows:?1?The Han curve can be used to describe the asphalt binders'phase structure.Both the loss elastic modulus and the storage elastic modulus decrease with the temperature increase under the same number of freeze-thaw cycles,and the complex shear modulus increase linearly with the number of freeze-thaw cycles increase.SBS modifier can promote asphalt binders'resistance to water-temperature aging,which can slow the linear growth trend of their complex shear modulus with freeze-thaw cycles.Further,the modified Vogel-Fulcher-Tammann equation can be used to characterize asphalt binders'complex viscosity with temperature during multiple freeze-thaw cycles.With an increase in temperature,the viscosity component of SBS modified asphalt binder increases,and the elastic component decreases.With an increase in the number of freeze-thaw cycles,the SBS modified asphalt binder material's%R_0.1.1 and%R_3.2under different stress levels show a decreasing trend,J_nr increase with an increase in the number of freeze-thaw cycles,and the SBS modified asphalt binder's stress sensitivity become stronger.?2?The 1700cm^-1 carbonyl group can be considered a characteristic marker peak of the KL-90 asphalt binder material that distinguishes other base asphalt binders.The infrared spectrum of SBS modified asphalt binder is a simple superposition of the spectrum of SBS modifier and base asphalt binders.The absorption peak area of the FTIR spectrum is calculated by taking the tangent of the lowest point on both sides of the absorption peak as the calibration baseline,and the reference peak range of 2000cm^-1650cm^-1 absorption peak area sum can be used as the FTIR quantitative method to analyze the adhesive material.The difference is obvious in asphalt binder material's chemical composition and characteristic functional group index in different rheological property parameters.The asphalt binder's complex shear modulus exhibite a multivariate linear relation with the change in the characteristic functional group index after multiple freeze-thaw cycles.?3?When the interlayer is completely continuous,the maximum shear stress-strain is mainly concentrated in the upper and middle layers,and tends to increase first and then decrease as the depth of the road increases.When the interlayer is completely smooth,the maximum shear stress-strain is at the interlayer sliding layer position,and when the interlayer is semi-continuous and semi-sliding,the slope of the longitudinal slope affects it under pressure-shear load combined.When the pavement's surface is in the upper,middle and lower layers,the shear stress-strain maximum appears in the pavement structure's depth at approximately 8cm¹0cm,while when the pavement's surface is in the upper and lower layers,the maximum shear stress-strain appears in the vicinity of the pavement structure's depth at approximately 6cm⁸cm.When the vehicle overload increases from 30%to 100%,the maximum shear stress peak increases nearly 2 times,and shows an increasing trend with the temperature increase.?4?When the number of hidden layer nodes in the shear strength prediction model is set to20,the number of network training iterations is 39,the sample error curve does not decrease for 6 consecutive iterations,and the model training completed has higher precision.In the entire network training,verification,and test data samples,the input and output value errors do not exceed±0.5.SBS modified asphalt is recommended as the adhesive layer,and the optimum amount determined is 1.2kg/m².With the temperature increase,different types of sample's interlayer shear strength decrease continuously,and the trend of the quadratic polynomial change.Further,different types of samples'interlayer shear strength decrease continuously and show a linear trend with an increase in the number of freeze-thaw cycles.?5?The shear fatigue failure life of the same adhesive layer sample decrease with an increase in the stress ratio,and the fatigue failure life is very sensitive to changed in the stress level.The shear fatigue failure life and stress level are related linearly in the double logarithmic coordinates.The interlayer shear fatigue failure life and loading frequency show an exponential change trend,the higher the loading frequency,the greater the sample's interlayer shear fatigue failure.The interlayer shear fatigue failure life of different types of samples decrease with the increase in the number of freeze-thaw cycles,and exhibite a linear trend.