TY - JOUR
T1 - Physicochemical and quantum chemical studies of the thermal-oxidative aging resistance of bitumen modified with isocyanate-based reactive additive
AU - Li, Tianshuai
AU - Luo, Sang
AU - Lin, Jiao
AU - Lu, Guoyang
AU - Liang, Dong
AU - Oeser, Markus
AU - Wang, Dawei
PY - 2023/12/8
Y1 - 2023/12/8
N2 - The use of methylene diphenyl diisocyanate (MDI)-based additives to prepare isocyanate-modified bitumen (IMB) provides an effective solution for achieving energy savings and performance improvements. However, the thermal-oxidative aging properties of bitumen modified with isocyanate additive have not been well discussed, which limits the fundamental understanding of its durability-related performance. To promote the understanding of the aging mechanism of IMB, experimental investigations and quantum chemical calculations were conducted to investigate the aging properties of IMB. IMB samples were prepared and aged under controlled laboratory conditions. The evolutions of aging behaviors were examined through physical and chemical approaches. The role of noncovalent intermolecular interactions in delaying oxidation was interpreted through density functional theory (DFT)-based theoretical calculation. The results revealed that amide-related bonds can be generated due to the chemical interactions between isocyanate and bitumen compounds. Chemical reactions tend to reduce the potential sites for oxidative attacks, thereby inducing delayed oxidation of IMB. Consequently, lower chemical and rheological aging indexes can be observed in IMB, and chemical crosslinking can provide effective support for the elastic response after aging. In addition, the noncovalent interactions between isocyanate and bitumen molecules can result in a lower tendency towards oxidation, which provides a cooperative effect on the inhibition of aging. The findings of this study offer insights into the aging behaviors of IMB and provide references for the design of chemically modified bitumen. © 2023 Elsevier Ltd
AB - The use of methylene diphenyl diisocyanate (MDI)-based additives to prepare isocyanate-modified bitumen (IMB) provides an effective solution for achieving energy savings and performance improvements. However, the thermal-oxidative aging properties of bitumen modified with isocyanate additive have not been well discussed, which limits the fundamental understanding of its durability-related performance. To promote the understanding of the aging mechanism of IMB, experimental investigations and quantum chemical calculations were conducted to investigate the aging properties of IMB. IMB samples were prepared and aged under controlled laboratory conditions. The evolutions of aging behaviors were examined through physical and chemical approaches. The role of noncovalent intermolecular interactions in delaying oxidation was interpreted through density functional theory (DFT)-based theoretical calculation. The results revealed that amide-related bonds can be generated due to the chemical interactions between isocyanate and bitumen compounds. Chemical reactions tend to reduce the potential sites for oxidative attacks, thereby inducing delayed oxidation of IMB. Consequently, lower chemical and rheological aging indexes can be observed in IMB, and chemical crosslinking can provide effective support for the elastic response after aging. In addition, the noncovalent interactions between isocyanate and bitumen molecules can result in a lower tendency towards oxidation, which provides a cooperative effect on the inhibition of aging. The findings of this study offer insights into the aging behaviors of IMB and provide references for the design of chemically modified bitumen. © 2023 Elsevier Ltd
KW - Aging mechanism
KW - Bitumen
KW - Isocyanate modification
KW - Physicochemical analysis
KW - Quantum chemical calculation
KW - Thermal-oxidative aging
UR - http://www.scopus.com/inward/record.url?scp=85173610971&partnerID=8YFLogxK
UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-85173610971&origin=recordpage
U2 - 10.1016/j.conbuildmat.2023.133427
DO - 10.1016/j.conbuildmat.2023.133427
M3 - RGC 21 - Publication in refereed journal
SN - 0950-0618
VL - 408
JO - Construction and Building Materials
JF - Construction and Building Materials
M1 - 133427
ER -