Research On The Improvement Of The Adhesion Between Granite And Asphalt And The Road Performance Of The Mixture

With the rapid development of China's transportation infrastructure and the impro vement of environmental protection awareness,high-quality medium alkaline aggrega tes and other non renewable resources are becoming increasingly scarce.In China,gra nite and other acid aggregates have the advantages of hard texture,wear resistance,ski d resistance,high mechanical strength,rich reserves and wide distribution.If granite is applied to the engineering construction of asphalt concrete pavement,it can not only a lleviate the shortage of medium alkaline stone resources,but also effectively reduce th e project cost and drive the local economic development.However,due to the hydroph ilicity and hydrophobicity of granite,the adhesion between asphalt and granite aggreg ate is insufficient,and the water stability of granite asphalt mixture is poor,which seri ously affects the application and promotion of granite asphalt mixture in road engineer ing.Therefore,how to improve the adhesion between granite aggregate and asphalt an d maintain or improve the road performance of granite asphalt mixture has become an important issue to be solved urgently.Based on the key transportation science and technology plan project of Shandong Province "Research on modification and application technology of granite in typical a sphalt pavement structure in Weihai area"(Project No.2017b12),this thesis selects Qi ng chuan rock asphalt,acyl amine anti stripping agent kh5 and fatty amine anti strippi ng agent aj-1 to modify the matrix asphalt.The influence of anti stripping agent on asp halt performance is studied through three indexes of asphalt.The blending technology of Qing chuan rock asphalt and amine anti stripping agent is proposed,and the optima l content of composite anti stripping agent is determined based on response surface me thod.Finally,the modification schemes of two groups of composite anti stripping agen t modified asphalt and three groups of single anti stripping agent modified asphalt are determined,compared with the matrix asphalt,and the effects of five groups of anti str ipping measures on the rheological properties and adhesion properties of asphalt are e valuated.The shear modulus,shear modulus and flexural fatigue properties of asphalt beam s before and after adding different asphalt rheometer,and the dynamic shear modulus and shear modulus of asphalt beams at high temperature were studied by using the fre quency domain rheometer.The test results show that for the modified asphalt with a si ngle anti stripping agent,the rock asphalt significantly improves the high-temperature properties of the base asphalt,but the low-temperature rheological properties are reduc ed;The improvement effect of acyl and fatty amine anti stripping agents is different fr om that of rock asphalt.Kh5 and aj-1 increase the viscosity of asphalt and improve the low-temperature performance of asphalt,but reduce the high-temperature performanc e.The composite modified asphalt has excellent high and low temperature performanc e,which makes up for the poor low temperature performance of rock asphalt and the l ack of heat resistance of amine anti stripping modified asphalt.In the wide frequency domain,five groups of anti stripping agents can improve the fatigue performance of m atrix asphalt,and the fatigue performance of composite modified asphalt is the largest.The order of high temperature deformation resistance is RAMA > AJ / RAMA > KH /RAMA > 70-A > AJMA > KHMA,the order of Low Temperature Rheological Proper ties of asphalt is KHMA > AJMA > KH / RAMA > AJ / RAMA > 70-A > RAMA,and the order of fatigue resistance is KH / RAMA > AJ / RAMA > RAMA > KHMA > AJ MA.Based on the surface free energy theory,the surface energy parameters of base as phalt and modified asphalt were measured by lying drop method,and the effects of dif ferent anti stripping agents on the surface free energy,dispersion component and polar ity component of asphalt were analyzed.The test results show that the five groups of a nti stripping agents can improve the surface energy of matrix asphalt,acyl and fatty a mine anti stripping agents can effectively improve the polarity component of surface e nergy parameters of matrix asphalt,rock asphalt can improve the dispersion componen t of surface energy parameters of matrix asphalt,and the polarity component and dispe rsion component of composite modified asphalt are greatly increased.At the same tim e,the surface energy parameters of aggregate are measured by cylindrical wick metho d.According to the surface energy theory,the cohesion work of asphalt material and th e adhesion work between asphalt and aggregate surface under dry and wet conditions are calculated,and the improvement effects of different anti stripping agents on the co hesion failure of asphalt and the adhesion failure between asphalt and aggregate are an alyzed.The water stability index between asphalt and aggregate is calculated accordin g to the adhesion work and peeling work of asphalt material.The order of adhesion im provement is KH / RAMA > AJ / RAMA > KHMA > RAMA > AJMA > 70-a.Using hydrated lime powder instead of some mineral powder filler,the effects of different anti stripping agents on the water stability,low-temperature crack resistance and high-temperature performance of granite asphalt mixture are studied through the f reeze-thaw splitting test,low-temperature bending test and rutting test of AC-13 granit e asphalt mixture.The test results show that hydrated lime powder can greatly improv e the water stability and high temperature stability of granite asphalt mixture,but there is still a large room for improvement.Hydrated lime powder replaces some mineral p owder fillers,which has little or reduced improvement on the low-temperature crack r esistance of granite asphalt mixture,and the low-temperature performance of granite a sphalt mixture composed of rock asphalt and hydrated lime powder is lower than the s pecification requirements.The addition of anti stripping agent improves the water stab ility and durability of granite asphalt mixture.The order of improvement effect is com posite modified asphalt > rock asphalt modified asphalt > acylamine anti stripping age nt > fatty amine anti stripping agent.