The rheological properties of the bituminous components （bitumen and bituminous mastic） within asphalt mixtures contribute significantly to the major distresses of flexible pavements （i.e. rutting, fatigue and low ...The rheological properties of the bituminous components （bitumen and bituminous mastic） within asphalt mixtures contribute significantly to the major distresses of flexible pavements （i.e. rutting, fatigue and low temperature cracking）. Asphalt mixtures are usually composed of mastic-coated aggregates rather than pure bitumen-coated aggre- gates. The purpose of this study is to investigate the effects of mineral fillers on the theological behaviour of several polymer-modified bitumens （PMBs） through laboratory mixing. A neat bitumen and two types of polymers （elastomeric and plastomeric） were used to produce PMBs, and two fillers with different minerals （limestone and basalt） were selected to obtain mastics. The dynamic shear rheometer （DSR） and bending beam rheometer （BBR） were used to characterize the theological properties of PMBs and mastics. In particular, multiple stress creep recovery （MSCR） tests were performed to evaluate the rutting potential at high temperatures, whereas BBR tests were carried out to investigate the low temperature behaviour of these materials. BBR results for unmodified mastics show that the increase of stiffness is similar regardless of the filler type, whereas results for polymer-modified mastics indicate that the degree of stiffening depends on the combi- nation of filler/polymer types. MSCR results show that adding filler leads to a reduced susceptibility of permanent deformation and an enhanced elastic response, depending on the combination of filler/polymer types. Overall results suggest that a physical-chemical interaction between the filler and bitumen occurs, and that the interaction level is highly dependent on the type of polymer modification.展开更多
基金supported by the Ministry of EducationUniversities and Research project"Damage and healing of innovative nano-structured and polymer-modified bituminous materials"(Grant RBFR10JOWO)under the"FIRB-Futuro in Ricerca 2010"funding program
文摘The rheological properties of the bituminous components （bitumen and bituminous mastic） within asphalt mixtures contribute significantly to the major distresses of flexible pavements （i.e. rutting, fatigue and low temperature cracking）. Asphalt mixtures are usually composed of mastic-coated aggregates rather than pure bitumen-coated aggre- gates. The purpose of this study is to investigate the effects of mineral fillers on the theological behaviour of several polymer-modified bitumens （PMBs） through laboratory mixing. A neat bitumen and two types of polymers （elastomeric and plastomeric） were used to produce PMBs, and two fillers with different minerals （limestone and basalt） were selected to obtain mastics. The dynamic shear rheometer （DSR） and bending beam rheometer （BBR） were used to characterize the theological properties of PMBs and mastics. In particular, multiple stress creep recovery （MSCR） tests were performed to evaluate the rutting potential at high temperatures, whereas BBR tests were carried out to investigate the low temperature behaviour of these materials. BBR results for unmodified mastics show that the increase of stiffness is similar regardless of the filler type, whereas results for polymer-modified mastics indicate that the degree of stiffening depends on the combi- nation of filler/polymer types. MSCR results show that adding filler leads to a reduced susceptibility of permanent deformation and an enhanced elastic response, depending on the combination of filler/polymer types. Overall results suggest that a physical-chemical interaction between the filler and bitumen occurs, and that the interaction level is highly dependent on the type of polymer modification.
