| With the rapid development of China’s transportation industry and the increase of the total mileage of the highway,there has been a sustained and rapid growth in demand and pressure for road maintenance,to this end,the competent authorities of the country have put forward the conservation policy of "prevention first,prevention and control combined",the conservation concept of "environmental protection,energy conservation,economy,and innovation",and advocate the development of low-input,low-consumption,high-efficiency,and high-quality conservation technologies.Based on these reasons,based on the experience of hot in-place recycling,double-decked paving and thin layer cover,a new technology of heating and laying thin layer cover is put forward,and through indoor and pavement test,the correlation between heating and thin layer mixture and bonding property between layers is analyzed.First of all,through the investigation of related literature,asphalt pavement and traditional maintenance technology,combined with the BISAR3.0 program and grey relational degree theory,it is found that the most common in the traditional thin layer pavement is the pavement disease caused by the interlayer shear stress,such as the lapse,the pack and so on,according to BISAR3.0 analysis,the maximum shear stress between layers decreases with the increase of thin layer thickness,and increases with the increase of friction parameter,load and horizontal force coefficient;the gray correlation degree of all four factors is greater than 0.65,which has a great influence on the interlaminar shear stress of the thin layer,but only the thin layer contact state can be easily improved.Secondly,on the basis of the investigation of the technical standard of asphalt cement used for thin layer mixture,four kinds of common thin layer asphalt(high viscosity asphalt,rubber modified asphalt,SBS modified asphalt and rubber powder/SBS composite modified asphalt)are compared,based on these,the study of rubber powder/high viscosity compound modified asphalt is put forward and carried out,it is concluded that the high-temperature,low-temperature and elastic recovery performance of the rubber/high-viscosity composite modified asphalt obtained by composite modification using 10%of 60 mesh rubber powder and 8%of high-viscosity adhesive exceeds the currently used SBS modified asphalt and rubber modified asphalt,compared with high viscosity asphalt,except for the low temperature performance,the high temperature and elastic recovery performance is close.At the same time,it also fully meets the "Technical Specifications for Highway Asphalt Pavement Construction"(JTG F40-2004)and NovaBinder technical specifications;The mixture ratio of the rubber powder/high viscosity compound modified asphalt in the laboratory was designed for the thin mixture of dense suspension,skeleton space and skeleton dense structure,and the optimum oil stone ratio of AC-10,SMA-10,Novachip-B and OGFC-10 were 5.2%,6.1%,5.4%and 4.8%,respectively.Thirdly,the road performance of four kinds of thin asphalt mixture is compared,the high temperature stability is Novachip-B>SMA-10>OGFC-10>AC-10.the low-temperature anti-crack properties were evaluated from the tensile strain ε b and the stiffness modulus Sb as Novachip-B>SMA-10>AC-10>OGFC-10 and Novachip-B>AC-10>SMA-10>OGFC-10,The anti cracking performance of temperature range from 5 to 25℃ is SMA-10>Novachip-B>AC-10>OGFC-10 by SCB test,and the water stability is AC-10>SMA-10>Novachip-B>OGFC-10.The anti-sliding performance evaluation indexes from the structural depth TD and friction coefficient BPN were OGFC-10>Novachip-B>SMA-10>AC-10 and Novachip-B>OGFC-10>SMA-10>AC-10,respectively.All meet the requirements of standardized technical indicators.Then,the interlayer shear test is done through indoor molding of thin layer rut plate specimens and cutting core samples,the interlaminar shear strength was used as an index to evaluate the effect of the original road surface type,the pavement heating temperature,the original road surface polishing state,the test temperature,and the water environment on the bond performance between layers.lt is found that the bond strength between layers increases with the increase of interlayer heating temperature.When the interlayer heating temperature reaches about 160℃,the bonding property between layers is the best.The interlayer heat treatment thin layer and the original pavement layer are interlocked as a unified whole,and there is a shear angle in the shear surface after the shear test,and the surface is uneven.The interlayer adhesion properties of the four thin pavement composite structures are SMA-13+SMA-10>AC-13+SMA-10>SMA-13+AC-10>AC-13+AC-10 in order;With the increase of the roughness of the original road surface,the adhesion between the layers of the heating overlay gradually increased;The influence of pavement water on interlayer performance is relatively small,while ambient temperature has great influence on interlayer performance.At the same time,the interlayer SCB and interlayer trabecular bending fatigue test are used to verify the interlayer properties of interlayer thermal bonding and interlayer viscous oil bonding,and the interlayer bonding performance is better than that of interlayer viscous oil.Finally,through the test road paving and testing,it is found that the interlayer bonding performance of the test road is lower than that in the laboratory test,but the adhesive performance advantage is larger than that in the best interlayer interlayer,which shows that the bonding strength between the heating and overlaying technology is greatly improved compared with the traditional thin layer technology.This summary puts forward that the recommended value of the interlaminar shear strength index of the heating overlay is more than 1.6MPa,and the other indexes are recommended in accordance with the specifications such as "Highway Asphalt Pavement Construction Specifications" and "Highway Engineering Quality Inspection and Evaluation Standards". |
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