Study On Asphalt Penetration Pre-coated Hot Macadam Mixture

The high temperature stability and anti-cracking performance of asphalt mixture are contradictory to the current design system and the common paving process.The continuous development of economy leads to the continuous increase of traffic volume.In addition,most of the asphalt pavement structures in China are semi-rigid base asphalt pavement or composite pavement with rigid base asphalt pavement.As a result,the damage phenomena such as high-temperature rutting and reflection cracking on the asphalt pavement occur frequently,and it is difficult to reconcile them.How to improve the deformation capacity of asphalt mixture on the premise of ensuring the resistance of rutting has become an urgent problem to be solved.The traditional asphalt penetration type pavement makes full use of the inlay between coarse aggregate and can achieve anti-rutting effect under certain conditions.However,the aggregate in the traditional asphalt penetration type pavement is not heated,which leads to the decrease of fluidity in the process of asphalt filling into the aggregate,and fails to completely wrap the aggregate,resulting in poor bond between the aggregates and easy to loose,peeling and other phenomena.In terms of construction technology,the traditional asphalt penetration pavement adopts the construction method of gradation paving,which makes some of the caulking materials unable to fill the gap of the main stone,resulting in a large gap ratio of the mixture,which cannot reach the compaction state.At the same time,the thickness of the construction layer is also limited.The thickness of the construction layer is the same as the maximum particle size of the main stone,which is usually no more than 5cm.The greater thethickness of the layer,the worse the road performance.The use of asphalt penetration pavement in China has become less and less.In order to overcome the shortcomings of the traditional asphalt penetration type pavement,a new type of asphalt mixture-premix hot gravel penetration type asphalt mixture is proposed in this paper,in order to improve the inherent contradiction between the anti-rutting and anti-cracking of the asphalt pavement and reduce the rutting and cracking of the asphalt pavement.The main work and research results of this paper are as follows:(1)the design method of premium-mix hot crushed stone penetrating asphalt mixture is put forward: 1)the gradation of premium-mix hot crushed stone penetrating asphalt mixture is designed by using the method of graded blending to ensure the formation of the skeleton;2)according to the idea of skeleton void volume filling to determine the penetration of asphalt or asphalt slurry(cement)required amount;3)determine the rotational viscosity of asphalt or slurry at different temperatures,according to the viscosity-temperature curve and asphalt penetration test to determine the penetration temperature of each cement;4)performance verification by rut test.The paper compares the anti-rutting performance of the pre-mixed hot gravel penetration type asphalt mixture prepared by various cementing materials,and selects the suitable cementing materials for the pre-mixed hot gravel penetration type asphalt mixture by comprehensively considering the performance,construction temperature,production cost and other factors of the mixture.(2)laboratory tests show that the premium-mix hot gravel penetration asphalt mixture not only has good high-temperature stability,but also has excellent tensile deformation capacity and crack resistance,and has a strong adhesion to the substrate,which overcomes the disadvantages of traditional asphalt penetration pavement materials and greatly improves its road performance.In particular,its tensile deformation capacity is much better than that of ordinary asphalt or modified asphalt mixture,and its anti-cracking performance is greatly improved.(3)compared with the stress absorption layer(e.g.,STRATA),the deformation capacity,stress dissipation and anti-cracking effect of the premium-mix hot gravel penetration asphalt mixture are better than that of the STRATAT stress absorption layer,and the anti-rutting ability of the premium-mix hot gravel penetration asphalt mixture is much stronger than thatof the STRATAT stress absorption layer,which can be used as the stress absorption structure layer.(4)compared with the casting type asphalt mixture premixed hot rock penetration type deformation of asphalt mixture,and the deformation coordination of steel bridge panel and with basic and casting bonding between the steel bridge deck asphalt mixture is,however,the high temperature stability is greatly better than that of the casting type asphalt mixture,difficult diseases such as rutting,the interlayer deformation,therefore,ready-mixed hot gravel penetration type asphalt mixture is expected to be applied in the steel bridge deck pavement.(5)using digital image processing technology and numerical simulation technology of premixed heat of gravel asphalt mixture mesoscopic analysis penetration type,visible premixed heat of gravel asphalt mixture injection type coarse aggregate is larger,the embedded crowded degree between the contact point is larger,the coarse aggregate distribution uniformity is good,stable skeleton structure,load can be directly through the contacts between the coarse aggregate particles to the grassroots,occurring in the process of stress strain and displacement is small,the ready-mixed hot gravel penetration type asphalt mixture with large ratio of while still have good high temperature stability.(6)according to the characteristics of mixed hot gravel penetration asphalt mixture,the applicable scope of the mixture is given,and the construction technology is discussed.Combined with premixed hot rock penetration the shaping method and characteristics of asphalt mixture with a synchronous paver,and introduces its working principle and operation method,realized the paving and compaction of premixed macadam while pouring the one-time synchronous paving of asphalt mortar,and can effectively meet the premixed macadam and construction temperature of asphalt mortar,improve the construction quality and efficiency.As a new type of asphalt mixture,premium-mix hot gravel penetration asphalt mixture has excellent deformation capacity,strong adhesion to the substrate,good waterproof and anti-cracking effect while ensuring good high temperature stability.The design and construction of thick layer(3～10cm)can be realized by overcoming the shortcomings of the stress absorption layer(such as STRTA,etc.)and the poor anti-rutting performance of castable asphalt concrete applied at high temperature.As the pavement stress absorptionstructure layer or the middle and lower surface layer of the bridge deck,this material has strong vertical resistance to rutting deformation,strong horizontal tensile deformation capacity,waterproof and anti-cracking,good durability,and is expected to be applied to the bridge deck pavement,stress absorption layer,anti-cracking structure layer and other fields,has a good application prospect.