Study On Preparation Technology Of SBS Modified Emulsified Asphalt

Styrene-butadiene-styrene copolymer(SBS)modified emulsified asphalt has the advantages of environmental protection,energy saving and high performance,which plays an important role in the maintenance of highway.However,in the preparation of SBS modified asphalt with high SBS content and its emulsion,there are many problems such as difficulty in emulsification and poor storage stability of the emulsion.In this paper,SK70#asphalt was selected as raw asphalt,SBS modified asphalt samples with different SBS content were prepared.The basic performance analyses and rheological performance tests were carried out.It was found when the SBS content was 6 wt.%,the macro-properties of modified asphalt were significantly improved,the softening point,ductility and penetration of the SBS modified asphalt were 82.7℃,25.6 cm and 56.9(0.1 mm)respectively.The microscope observation showed that the distribution of SBS in asphalt changed from the "island" structure to the network structure under that content.This network structure limited the viscous deformation of the SBS modified asphalt,and improved its viscoelasticity.So,the performance of the SBS modified asphalt was greatly improved.Fluid dynamics test results showed that the phase angle of the SBS modified asphalt was smaller,and it still satisfied G*/Sinδ≥1.0kPa at 90℃.More,the anti-rutting performance of the SBS modified asphalt was excellent,and the loss factor was close to 1 in the test frequency range,and the storage modulus was large.At the same time,it also had good resistance to creep,the creep recovery under 3.2 kPa was higher than 80%.Subsequently,the influence of four viscosity reducers on the performance of SBS modified asphalt was investigated.The viscosity reducer DV-4 can reduce the viscosity of the mixed system at high temperature and improve the rutting resistance of modified asphalt,which is an ideal modification additive for improving the propertiy of the the SBS modified asphalt.Then,after determining the composition of raw material,this paper further optimized the emulsification conditions.Under the optimized conditions,a modified asphalt emulsion with a solid content of 59.9%can be obtained.The results of particle size and distribution showed that the proportion of 1-10 μm particles in emulsified asphalt reached 88%,and the distribution was steady.The storage stability after 1 day and 5 days were 0.8%and 4.7%.The road test results showed that SBS modified asphalt emulsion has good sealing performance,and the recommended spraying amount is 0.2 kg/m2.