The Research On Performance Of Complex-modified Asphalt Patching Material With SBS-rubber Powder-nano SiO₂

To the asphalt pavement of high-grade highways especially of the express way inour country，it is urgent to improve the performance of asphalt binder，the servicelever and the using-age of the road because of the increasing traffic flow，heavy-loadvehicles and over-loading trucks．Using polymer to modify asphalt has been a validmethod and a developing direction to rnend the application performance of asphalt．In this thesis， modified asphalt was modified by four modifiers （Waste rubberpowder，SBS，SBR and nano-SiO₂），and waste rubber powder modified asphalt，waste rubber powder，SBS and nano-SiO₂complex-modified asphalt，waste rubberpowder, SBS and nano-SiO₂complex-modified asphalt and SBS/SBR modifiedasphalt were prepared．Through the traditional tests，such as penetration，soften pointand ductility，and thermal weight loss test，microstructure of modified asphalt wascharacterized by microscope．Effect of polymer modifiers to the modified asphaltwere investigated．（1） A waste rubber powder modified asphalt were prepared，and after the effectsof amount and size of waste rubber powder were been discussed，we have set up：WithContent of rubber powder increase，low temperature penetration degree of asphaltincreases，the asphalt’s softening point has improved obviously，and the penetrationdegree reduces．The test proves that the content of the rubber powder is relativelygood in25%，and the better size of the rubber powder is in0.18mm．（2） Waste rubber powder，SBS and nano-SiO₂complex-modified asphalt wereprepared by direct shear．The effects of shearing time，temperature and amount ofmodifying agent on the morphology，softening temperature，penetration degree andductility of modified asphalt were discussed．Their common technical performancewere tested．The results show that the modified asphalt containing25wt.%of wasterubber powder，5wt.%SBS and0.05wt.%nano-SiO₂achieve optimal performancewhen the mixing temperature is at180℃，the mixing time is6h．The softening pointincreased63%，ductility at5℃increased by600%in comparison with originalasphalt．（3） Waste rubber powder，SBS and nano-SiO₂complex-modified asphalt andwaste rubber powder，SBS and nano-SiO₂complex-modified asphalt were prepared byadd to different variety SBS and SBR dosage．The effects of different variety SBS andSBR dosage to the modified asphalt were been discussed．The test results show that with the content of polymer modifiers increased，both of the performance of modifiedasphalts were improved. The SBS modified asphalt has a better performance insoftening point，and the SBR is better than the one using SBS in low temperaturepenetration degree．...