TY - JOUR
T1 - Rheological behavior of a low crystallinity polyolefin-modified asphalt binder for flexible pavements
AU - Zhao, Xiaofei
AU - Rahman, Minhaz Ur
AU - Dissanayaka, Tharanga
AU - Gharagheizi, Farhad
AU - Lacerda, Carla
AU - Senadheera, Sanjaya
AU - Hedden, Ronald C.
AU - Christopher, Gordon F.
N1 - Funding Information:
We gratefully acknowledge the support of the Texas Dept. of Transportation through Project 0-6868, " Novel Material Systems for the Next Generation of Flexible Pavement Systems .".
Publisher Copyright:
© 2021 The Authors
PY - 2021/12
Y1 - 2021/12
N2 - An asphalt binder (PG 64−22) is modified with a crystallizable copolymer of polypropylene (PP) and polyethylene (PE) to enhance its ability to resist rutting in flexible pavements during periods of warm weather. After cooling of binders from the mixing temperature at a controlled rate of 3 °C/min, their microstructure and rheological behavior are characterized. The modified asphalts exhibit two-phase morphology with droplets of a maltene-rich polymer phase less than 50 μm in size dispersed in an asphaltene-rich, continuous phase. X-ray diffraction patterns and optical birefringence microscopy indicate that the PP/PE copolymer segregates from the matrix during cooling, forming a network of interconnected, crystalline fibrils. At temperatures of (50–80) °C, at which rutting is an issue in pavements, addition of PP/PE copolymer substantially increases the rutting factor by a factor of 2–6, depending on temperature and concentration. At temperatures of (―20 to 0) °C, addition of 5 wt.% or less of the PP/PE modifier has a minimal impact on performance based on both s-value and m-value. The modified asphalts are s-controlled, with ΔTc less than about 6.4 °C, suggesting that the PP/PE copolymer is an effective modifier for reducing rutting in flexible pavements.
AB - An asphalt binder (PG 64−22) is modified with a crystallizable copolymer of polypropylene (PP) and polyethylene (PE) to enhance its ability to resist rutting in flexible pavements during periods of warm weather. After cooling of binders from the mixing temperature at a controlled rate of 3 °C/min, their microstructure and rheological behavior are characterized. The modified asphalts exhibit two-phase morphology with droplets of a maltene-rich polymer phase less than 50 μm in size dispersed in an asphaltene-rich, continuous phase. X-ray diffraction patterns and optical birefringence microscopy indicate that the PP/PE copolymer segregates from the matrix during cooling, forming a network of interconnected, crystalline fibrils. At temperatures of (50–80) °C, at which rutting is an issue in pavements, addition of PP/PE copolymer substantially increases the rutting factor by a factor of 2–6, depending on temperature and concentration. At temperatures of (―20 to 0) °C, addition of 5 wt.% or less of the PP/PE modifier has a minimal impact on performance based on both s-value and m-value. The modified asphalts are s-controlled, with ΔTc less than about 6.4 °C, suggesting that the PP/PE copolymer is an effective modifier for reducing rutting in flexible pavements.
KW - Asphalt binder
KW - Crystallinit
KW - Polymer
KW - Rheology
UR - http://www.scopus.com/inward/record.url?scp=85111532291&partnerID=8YFLogxK
U2 - 10.1016/j.cscm.2021.e00640
DO - 10.1016/j.cscm.2021.e00640
M3 - Article
AN - SCOPUS:85111532291
VL - 15
JO - Case Studies in Construction Materials
JF - Case Studies in Construction Materials
SN - 2214-5095
M1 - e00640
ER -