Preparation And Performance Of 3D Printable TPSiV/SBS/CR Composite Modified Asphalt Sealant

Due to the fact that the modified asphalt sealing material has a good repair effect and low production cost,it has been widely used in pavement crack repair.However,when it is used for1-2 years,it often cracks again due to aging,so there are still problems such as insufficient adhesion,flexibility,and durability.3D printing technology,with its advantages of automation,precision,and speed,has been initially applied in the field of road engineering.With the increasing maturity of 3D printing technology,the time,cost,manpower and workers’safety risks of asphalt pavement maintenance will be reduced.Therefore,the development of high-performance sealing materials with excellent resistance to high and low temperatures,adhesion,and aging resistance to reduce pavement disease and extend the service life of the road is of great significance.Due to the characteristics of thermoplastic vulcanized silicone rubber（TPSiV）with stable structure,good weather resistance,high strength and elasticity of thermoplastic polyurethane,in this study,firstly,TPSiV as the main modification component,together with other modifiers to prepare the composite modified asphalt sealing material.At the same time,its related properties and modification mechanism were studied in detail.Secondly,3D printability is preliminarily discussed.Finally,the use effect of sealing materials is verified through solid engineering.The specific research contents are as follows:（1）Adopt 90#asphalt as the base asphalt,TPSiV,styrene-butadiene-styrene block copolymer（SBS）,and waste rubber powder（CR）as modifiers,TPSiV/SBS/CR composite modified bitumen crack sealant was prepared by the high-speed shear method.The influence of the preparation process and modifier content on the performance of modified asphalt was studied by controlling variable methods.The pavement performance indexes such as softening point,penetration,elastic recovery rate,and fluidity of sealant were taken as the criteria to determine the best preparation process and optimal admixing quantity of sealing materials.At the same time,the appropriate mesh number of waste rubber powder is optimized.Based on all pavement index tests of heating sealing materials,the formula of sealing material satisfying the index was determined,including high-temperature type and ordinary type.The optimal mass ratio of the formula was TPSiV:SBS:CR:CaCO₃:FEO=3:5:22:3:5.（2）Based on the above optimum formula sealing materials,the effects of SBS,CR,TPSiV,and their dosage on the rheological properties at high and low temperatures and the anti-aging properties of sealing materials were researched.The rheological properties of sealant were researched by temperature scanning,frequency scanning,and multiple stress creep tests utilizing a dynamic shear rheometer.The low-temperature features of sealant were investigated by a low-temperature bending beam rheometer.The anti-aging features were studied by rotating film,pressure aging,and ultraviolet aging tests.The results show that the use of TPSiV could improve the rutting factor and recovery rate of the modified pitch,and reduce the temperature and pressure sensitivity of the modified pitch.At the same time,it also improves the low-temperature performance and anti-aging performance of the sealing material.Compared with anti-ultraviolet aging,the anti-thermal oxygen aging property is more prominent.（3）The modification mechanism of the sealant was studied by fluorescence microscopy,scanning electron microscopy（SEM）,infrared spectroscopy（IR）,and thermogravimetric analysis（TG）.Fluorescence microscopy and SEM images showed that TPSiV,SBS,and CR were uniformly dispersed in the composite-modified asphalt and formed a stable structure.The IR results showed that the characteristic absorption peak of TPSiV modifier C=O at 1717 cm^-1disappeared after modification,but the characteristic absorption peak of SBS and rubber powder still existed,indicating that chemical modification and physical modification existed simultaneously in the TPSiV/CR/SBS modified asphalt sealing material.TG results showed that the decomposition temperature of all modified asphalt experience an improvement and is higher than that of matrix asphalt.This trend increases with the increase of TPSiV content,indicating that the modification of TPSiV is beneficial to improving the thermal stability of sealing materials.（4）The printability of sealing materials is preliminarily studied by using 3D printing technology,and the repair effect of 3D printing technology is studied by simulating crack repair.The results show that the sealing material can be extruded and has certain strength at a printing temperature of 130℃and printing speed of 300mm/min,and can be printed into strip shape and round shapes,indicating that the sealing material has certain printability.The crack repair results show that the adhesive effect between the repair material and the crack surface is good after the spraying of silane coupling agent KH550.（5）Finally,the sealing material is applied to the solid project in Taizhou,Zhejiang Province,and the optimal construction technology is proposed through the detailed study of the influence of each process on the final repair performance.The repairing effect of sealing materials was verified by combining it with the field detection index,and the sealing effect of sealing materials was tracked and detected after 6 months.The results showed that the sealing material prepared in this work has good pavement performance and meets the actual demand of pavement maintenance.