Study On The Storage Efficiency Of SBS Modified Asphalt And The Improvement Measures Based On Carbon Nanotubes

SBS modified asphalt is currently the most widely used polymer modified asphalt in asphalt pavement construction.Its microstructure is composed of asphaltene-rich asphalt phase and polymer-rich SBS phase.The incompatibility of the two-phase structure As a result,SBS modified asphalt is prone to phase separation during storage and transportation,that is,segregation.Especially in the case of long storage time and high temperature in the mixing station,the segregation induces the rapid deterioration of the performance of SBS modified asphalt,which seriously affects the durability of SBS modified asphalt pavement.At present,most studies focus on the thermal stability of SBS modified asphalt,ignoring the effect of storage aging and micro phase on its macro performance.In view of this,based on the research on the storage timeliness of SBS modified asphalt and the mechanism of thermal storage stability,this paper puts forward measures to improve the thermal stability of SBS modified asphalt,understand the performance attenuation law of SBS modified asphalt and give storage suggestions,for SBS modified Provide technical support for the development of natural asphalt technology.This article firstly explores the storage timeliness of SBS modified asphalt in actual engineering with a 10-day segregation test.The penetration characteristics,softening point,and ductility are used to characterize the change of its macroscopic characteristics,the shear stress curve is used to characterize the attenuation of the SBS network structure,the fluorescence micrograph is used to characterize the change of the polymer phase state,and the infrared spectrum is used to estimate the relative content of SBS.Variety.Studies have shown that there are many factors that affect the storage timeliness of SBS modified asphalt,including two-phase segregation,aging,and SBS degradation;with the increase of storagetime,the SBS content of the upper part of the stored asphalt first increases and then stabilizes,and the lower SBS content first After the reduction,it tends to be stable;during the storage process,although the strength of the upper network will increase first and then decrease,on the whole,the strength of the network will slowly decay,and the strength of the lower network will gradually decrease.Therefore,in order to avoid its performance degradation,the road performance will change.Poor,the storage time should be reduced as much as possible,and the storage time should not be more than 4 days.Secondly,the thermal storage stability mechanism of SBS modified asphalt was studied by combining macro and micro methods.At the macro level,the effects of storage temperature,storage time and matrix asphalt oil source on the performance attenuation of SBS modified asphalt during thermal storage were discussed;at the micro level,the changes in the relative content of SBS were analyzed by infrared spectroscopy and analyzed by means of atomic force microscopy Interface characteristics of modified asphalt.Studies have shown that: the longer the storage time,the more severe the separation of the SBS phase and the asphalt phase,the more obvious the performance attenuation of SBS modified asphalt;the higher the storage temperature,the greater the Brownian motion will accelerate the performance degradation of SBS modified asphalt;from the storage time 1.From the perspective of storage temperature,storage at low temperature and short time is beneficial to slow down the phase separation of SBS modified asphalt;different matrix asphalt oil sources have different components and different sensitivity to sulfur stabilizers.When modifying asphalt,the amount of external admixture should be determined according to the actual situation;the interface between SBS and asphalt is relatively smooth,while Carbon Nanotubes(CNTs for short)are significant in enhancing and improving the interface and adhesion of polymer asphalt The effect helps to enhance the storage stability of polymer modified asphalt.Finally,the thermal stability of SBS modified asphalt was improved by adding CNTs.Type I CNTs(untreated CNTs)and type II CNTs(polymer particles rich in CNTs)were selected to modify SBS modified asphalt.The optimal content of CNTs in CNTs / SBS composite modified asphalt was determined,and the improvement effect of CNTs on the thermal stability of SBS used asphalt during the ten-day separation process was analyzed.Studies have shown that both type I CNTs and type II CNTs can significantly improve thestorage stability of SBS modified asphalt.When the amount of type I CNTs is 0.5% and the amount of type II CNTs is 1.5%,the improvement effect of thermal stability The most obvious;in terms of improving performance degradation during storage,type II CNTs are superior to type I CNTs,and in improving internal molecular flow during storage,type I CNTs are superior to type ? CNTs.