Y. Zhang
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6 records found
1
Lignin, one of the most abundant natural polymers, has been extensively studied as liquid or solid additive in bituminous binders. Despite the fact the organosolv lignin in bitumen improves the overall resistance against oxidative aging, lignin could lead to binders of high thermal cracking sensitivity. In this study, a bio-based oil is implemented in a lignin modified bitumen to ameliorate characteristics, such as fatigue and thermal cracking resistance. Pressure aging vessel conditioning was applied to new binders formulated by different proportions of bio-oil to simulate the long-term aging. A series of rheological tests were performed. Based on the linear amplitude sweep test results, fatigue damage of lignin-bitumen could be reduced by increasing the oil content. According to relaxation test results, the addition of oil significantly decreased the ratio of residual stress and relaxation time. This study has shown preliminary conclusions on the use of bio-oil to improve the low-intermediate temperature performance of lignin-bitumen binders.
Lignin, as a bio-based waste, has been utilized in the asphalt industry due to various advantages. This study aimed to investigate the effects of two lignin products (lignin powder and lignin fiber) on the mechanical properties of asphalt mixtures. The raveling, rutting, thermal and fatigue cracking resistance, and moisture susceptibility of different asphalt mixtures were respectively evaluated by the Cantabro test, wheel loading tracking test, semicircular bending test, four-point beam bending test, and freezing-thaw cyclic test. Results show that asphalt mixture with lignin powder-modified asphalt improved the overall mechanical performance. However, lignin fiber showed contradictory effects on certain mechanical properties, i.e., improved rutting resistance and thermal cracking resistance of asphalt mixture, degraded abrasion resistance, fatigue performance, and moisture stability. Therefore, cautions need to be taken when incorporating lignin fiber into asphalt mixture.