Performance Study Of Anti-freezing Ice Semi-flexible Pavement On Concrete Bridge Deck

In the high mountain area of Yunnan,Guizhou,Sichuan,due to the influence of the environment,the bridge deck is frozen before the road surface.When vehicles are from ice-free pavement to frozen bridge deck,drivers can not deal with sudden changes in time.At the same time,the bridge is located at the key node of the route,and can not flexibly adjust and increase the traffic conditions,which can easily lead to traffic accidents,reduce the operational efficiency and cause huge economic losses.Daily deicing of bridge deck mostly adopts the method of spreading industrial salt.Although this method can effectively deicing,it consumes a lot of manpower,material and financial resources,and industrial salt has a corrosive effect on bridge and surrounding environment.In view of this problem,this paper innovatively proposes the use of anti-freezing ice semi-flexible pavement,in order to alleviate the problem of concrete deck ice,ensure the safety of vehicles and reduce the occurrence of traffic accidents.In addition,due to the lack of research on this technology at home and abroad,this paper will evaluate the durability of this deicing method.In this paper,through single factor analysis of material proportion,the range of each component of anti-freezing ice mortar is determined by experimental study,and the performance of the mortar meets the requirements of Technical Guidelines for the Application of Semi-flexible Pavement.It is found that the addition of anticoagulant ice agent can improve the mechanical properties of the mortar.From the SEM images,it can be seen that the mortar with appropriate amount of anticoagulant ice agent fills more hydration products in the pore space of the mortar than that without anticoagulant ice agent,which improves the mechanical properties of the hardened mortar.Through conductivity test,it is proved that anticoagulant can be precipitated from the specimens of anticoagulant ice slurry under the action of concentration gradient.Through five factors and four levels orthogonal test of cement,F:G(ratio of fly ash to blast furnace slag),calcium hydroxide,water and anticoagulant,the optimum mix ratio of orthogonal test is obtained.The final mix ratio of the anti-freezing ice mortar is obtained by adjusting the amount of anti-freezing ice agent,and the mix ratio can meet the technical requirements of Technical Guidelines for the Application of Semi-flexible Pavement.Through the experimental study on pavement performance and interlayer performance of anti-freezing ice semi-flexible bridge deck pavement,the high temperature stability,water stability and shear strength are improved with the increase of void fraction and grouting volume of parent asphalt mixture,and are better than AC-13 performance.In terms of low temperature performance,the best is 17.75% voidage,21.45% voidage,and finally AC-13 and 24.51% voidage.In terms of interlayer performance,17.75% voidage<21.45% voidage< 24.51% voidage.In a word,the properties of anti-freezing ice semi-flexible mixtures formed by grouting under different void fractions meet the requirements of specifications.Finally,the anti-freezing performance of semi-flexible pavement with anti-freezing ice is evaluated by three test methods.It is proved that the anti-freezing performance of upper 24.51% voidage> 21.45% voidage > 17.75% voidage.The more the grouting amount,the better the anti-freezing performance.The best anticoagulant ice effect is 24.51% voidage rutting plate,which can ensure the effective temperature is-3? and has anticoagulant ice effect within 3 hours at-4?.In terms of the effective time of anticoagulant ice,combined with the annual rainfall of 1000 mm in the humid area of Yunnan,Guizhou,Sichuan,the effective time of anticoagulant ice of three kinds of graded rut boards was estimated by data fitting with Origin 2017 software through wheel rolling test.The effective time of anticoagulant ice of three kinds of graded rut boards was respectively: void ratio 17.75%:2.06 years,void ratio 21.45%:2.22 years,void ratio 24.51%:2.54 years.Based on the above experimental study,the semi-flexible deck pavement with anti-freezing ice has been successfully developed in this paper,which can alleviate a series of problems caused by deicing with salt spraying method.The durability evaluation shows that the longest effective time of anti-freezing ice is 2.54 years,but it can alleviate the problem of deck icing in two winters,help to ensure traffic safety and improve transport efficiency.Compared with the manpower,material and financial resources consumed by frequent artificial salt spraying and deicing every year and the damage to the environment,it has more social and economic value.In addition,it provides a basis for further research on semi-flexible pavement with anticoagulant ice.