Study On Storage Stability Of SBS/REOB Composite Modified Reclaimed Asphalt And Its Effect On Performance Of Mixture

By the end of 2022,the total number of motor vehicles in China would reach 412 million and the Recycled Engine Oil Bottom(REOB)would be recycled 2.9 million tons annually,of which 20%-30% would be recycled engine oil bottom(Re OB).The effective utilization of waste oil residue has become the key content to save resources and protect environment.With the support of "Study on the Influence and Mechanism of Waste Oil Residue on Asphalt Modification Properties"(ZR2016EEM42)of Natural Science Foundation of Shandong Province,it was found that waste oil residue(REOB)can realize the recycling of aging asphalt,but its low temperature crack resistance and fatigue properties need to be further improved.Therefore,based on "Study on Preparation and Pavement Performance of SBS/REOB Composite Modified Reclaimed Asphalt"(2021B11),a REOB/SBS composite modified reclaimed asphalt technology was proposed in this paper,and the storage stability and mechanism of SBS/REOB composite modified reclaimed asphalt were studied in combination with the advantages of SBS modifier.The influence of storage stability on the pavement performance of the mixture was analyzed,and storage suggestions were given.The results are as follows:First,the storage timeliness of SBS modified asphalt and SBS/REOB composite modified asphalt was investigated with the segregation time of one week.The macroscopic properties of the upper and lower samples were characterized by the penetration degree and softening point,and the attenuation of the network structure of SBS modified asphalt and SBS/REOB composite modified asphalt was characterized by shear stress curve.Fluorescence micrograph was used to characterize the change of polymer phase state,and differential scanning calorimetry(DSC curve)was used to characterize the change of heat absorption.The results show that with the increasing segregation days,the SBS content in the upper sample of SBS modified asphalt and SBS/REOB composite modified asphalt increases first and then flattens,while the SBS content in the lower sample decreases first and then becomes stable.During a storage procedure,the upper and lower network strength increases first and then decreases.Therefore,to avoid performance degradation affecting the road performance,the storage duration should not exceed three days.Secondly,the thermal stability of SBS modified asphalt and SBS/REOB composite modified asphalt was studied by adding stabilizer.From the macro level,the performance changes of SBS+W(W refers to stabilizer)and SBS/REOB+W in the thermal storage process under different storage time and temperature are discussed.From the microscopic level,the change of SBS phase distribution was analyzed by fluorescence micrograph,and the curve fluctuation of heat absorption was analyzed by DSC map measured by differential scanning calorimeter.The results show that the stability of SBS+W and SBS/REOB+W is improved by the stabilizer under the condition of prolonged time,but it does not improve the stability under the condition of increasing temperature.Finally,the stability of asphalt mixture matrix,REOB,SBS,SBS+W,SBS/REOB and SBS/REOB+W at high temperature,low temperature and water were evaluated and analyzed by rut test,low temperature bending test and freeze-thaw splitting test.The results show that the addition of stabilizer makes SBS/REOB+W less sensitive to high temperature and better stable at high temperature.It can be seen from the low temperature trabecular bending test that the cracking resistance of the modified asphalt mixture mixed with stabilizer is better at low temperature,but the cracking resistance of SBS/REOB and SBS/REOB +W is poor.According to the analysis of freeze-thaw splitting test,the stabilizer also improves the water stability of single modified asphalt mixture or compound modified reclaimed asphalt mixture without stabilizer to some extent.