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The large-scale application of bamboo has led to the production of enormous amounts of waste in the form of bamboo residue. In order to reuse the bamboo residue, three types of bamboo fiber (sinocalamus affinis fiber (SAF), green bamboo fiber (GBF), and phyllostachys pubescens fiber (PPF)) extracted from bamboo residues were studied. The properties of bamboo fiber modified asphalt were evaluated by ductility test, cone penetration test, rheological test, and low-field nuclear magnetic resonance (LF-NMR) test. Furthermore, the dispersion properties of bamboo fiber were analyzed by dispersion uniformity test. The results show that the mechanical and high-temperature properties of the bamboo fiber modified asphalt are obviously improved while the low-temperature crack resistance is only slightly weakened. Meanwhile, the signal intensities of SAF modified asphalt and GBF modified asphalt are basically the same before and after aging. It proved the viscosity is not changed much, which verified the good anti-aging properties of SAF modified asphalt and GBF modified asphalt. However, PPF is the best dispersed uniformly in the asphalt. The maximum allowable length and dosage of bamboo fibers is recommended as follows: SAF (9 mm, 2.0%), GBF (6 mm, 1.5%), and PPF (6 mm, 2.0%). The application of bamboo residue in asphalt not only emphasizes the recycling value of bamboo residue waste but also provides an optional natural fiber material for asphalt pavement construction, which meets the requirements of sustainable development. [ABSTRACT FROM AUTHOR]

The comprehensive utilization of waste cooking oil (WCO) and waste engine oil (WEO) is of great significance to build a sustainable society because recycling WCO and WEO to develop a rejuvenator for asphalt pavement not only aids the reduction of environmental pollution, but also brings about significant benefits to the Earth's sustainable development. With a clear aim to contribute to a more efficient reuse of the waste oils and recycled asphalt mixtures, this paper develops a high-efficiency compound rejuvenator and determines the optimal combination of its main constituents (WCO and WEO) through orthogonal tests. Furthermore, the performance of the rejuvenator is verified by means of the four-fraction test and the traditional asphalt performance tests (penetration, ductility, softening point). These tests confirm the regeneration efficiency of the compound rejuvenator, and the optimum dosage of the compound rejuvenator is found of 7%. Subsequently, the mechanism of the compound rejuvenator in aged asphalt is examined, and following the application of the compound rejuvenator, it was concluded that the reclaimed asphalt pavement (RAP) could be maximized by 45%. Consequentially, the results of this research promote the recycling of WEO, WCO, and waste asphalt pavement materials, ultimately advocating the sustainability of pavement construction. [ABSTRACT FROM AUTHOR]

To enhance the performance of bio-asphalt, an attempt was made to modify bio-asphalt using graphene oxide (GO). Two bio-asphalts were prepared and modified with different GO dosage levels of 0 to 0.08% to obtain GO-modified bio-asphalts (GOMBA). The two GOMBA were tested in the conventional properties (penetration, softening point, and ductility), high- and low-temperature rheological properties, and aging properties. The results showed that the penetration decreases and the ductility increases slightly with the increase in the dosage of GO, while the softening point increases stably to the maximum by 17.84%, and 15.99% for the two GOMBA, respectively. GO is beneficial to improve the high temperature performance and the recovery after the deformation of the GOMBA; on the contrary, it does not significantly affect the low temperature cracking resistance of those. The maximum residual penetration ratio is 10.58% and 8.84%, respectively, and the maximum residual ductility is 10.79% and 27.51%, respectively, for the two GOMBA after short-term aging. GO modification plays a role in the change of carbonyl index (CI) and sulfoxide index (SI) of the GOMBA before and after aging based on the FT-IR spectra, indicating that the GO can effectively improve the antiaging performance of bio-asphalt. [ABSTRACT FROM AUTHOR]

In order to reuse waste resources (waste engine oil and waste asphalt mixture), the regeneration process of waste oil on aged asphalt is systematically explained. The BA was treated by aging test, and the basic mechanical properties, molecular dynamics simulation, and infrared spectrum test were carried out on this basis. The results showed that the WEO can restore the physical properties of the aged asphalt, and the recommended amount of WEO is 3%. The density of the asphalt model corresponds to the actual situation of the asphalt. The aged asphalt components are more aggregated. After the WEO was added, the components of asphalt aggregation were reduced and the diffusion ability was improved. Finally, infrared spectroscopy tests were conducted on asphalt specimens, and the results showed that the process of rejuvenated asphalt was dominated by physical reactions. Consequentially, the results of this study build a bridge between the performance and simulation of aged asphalt rejuvenated by WEO. Consequentially, the results of this research promote the recycling of WEO and waste asphalt pavement materials, ultimately advocating the sustainability of pavement construction. [ABSTRACT FROM AUTHOR]

Styrene-butadiene-styrene (SBS) modified asphalt used in road engineering is a complicated mixture of various compositions. The present study was undertaken to evaluate the influence of different raw materials and their content on the moisture stability of SBS copolymer modified asphalt mixture. A total of 18 different combinations of base asphalt, SBS, furfural extract oil (FEO), and stabilizer were considered to prepare different SBS modified asphalt samples, and the contact angle test was carried out to determine the work of adhesion and the work of debonding of SBS modified asphalt with aggregate. Moreover, a multi-factor Analysis of Variance (ANOVA) was conducted to investigate the statistical effects of the material composition factors. The results show that the bond strength between SBS modified asphalt and aggregate is significantly affected by the source of base asphalt, but it is insensitive to the change of SBS type under dry and wet conditions. Besides, the moisture damage resistance of SBS modified asphalt improves firstly and then reduces with the rising storage of SBS, FEO, and stabilizer. Furthermore, linear regression analysis suggests that the work of adhesion under dry condition has excellent correlation with the work of debonding under wet condition. [ABSTRACT FROM AUTHOR]

To determine and compare the fracture properties of different asphalt mixtures, single-edge notched beam (SENB) tests using three types of asphalt mixtures were applied in this study under the conditions of different notched depths and different temperatures. The effects of notched depths and temperatures on the fracture toughness and fracture energy were analyzed. The results indicate that the notch depth has no significant effects on the fracture toughness and the fracture energy, but the gradation has relatively obvious effects on the fracture energy, which the larger contents of course aggregate leads to increase the discreteness of the fracture energy of the specimen. The temperature has significant effects on the ultimate loads, fracture energy, and fracture toughness. The ultimate loads of the SENBs reach the peak value at 0°C, which could be resulted in that viscoelastic properties of asphalt mixture depend with temperatures. The fracture toughness at −20°C of continuously graded asphalt mixtures are higher than those of gap-graded asphalt mixtures. On the contrary, the fracture toughness of gap-graded asphalt mixtures is higher at temperatures from −10°C to 20°C. The fracture energy increases with temperatures, and the fracture energy of SMA-13 is significantly larger than those of AC-13 and AC-16. [ABSTRACT FROM AUTHOR]

To observe the micro-morphology of high modulus asphalt binders (HMABs), a scanning electron microscope (SEM) and a fluorescence microscope were employed. To evaluate the performance characteristics of mixtures using these binders, laboratory mixture tests were conducted. The binder morphology showed that the particle size of high modulus modifiers, PR PLAST S® (PRS) and PR PLAST Module® (PRM), and the relative viscosity of modified asphalt increased with time; PRS modifier droplets tended to form a network. The test results of the mixtures indicated that compared with the original asphalt mixture and the styrene–butadiene–styrene (SBS) mixture, the HMABs significantly improved the high temperature performance, water stability, moisture–heat synthesis property, and dynamic modulus of mixtures. The investigation results of test sections showed that the average rut depth and surface deflection observed in the test sections using the high modulus asphalt concretes (HMACs) were much smaller than those in the test sections using the SBS mixture after one year of service. Based on the colloidal system equilibrium and the lowest energy principle, the modification mechanism of the HMABs modified by PRS and PRM was analyzed in this paper by using the effects of swelling and interface layer. The effects of the HMABs on the performance of HMACs were evaluated. The test results of the mixtures confirmed the correctness of the analysis associated with the modification mechanism. [ABSTRACT FROM AUTHOR]

Bamboo fiber (BF) is a type of plant fiber obtained directly from bamboo plants or from waste bamboo residue, which can be used as an asphalt modifier. Rational planning and regular cutting of bamboo forest will promote its growth, thus improving the effect of carbon sequestration and absorption. The use of bamboo products is now widespread, and the reuse of waste bamboo residue will reduce smoke pollution from incineration. This paper outlines the preparation method and surface treatment of bamboo fiber, its characteristics, preparation parameters, basic and rheological properties and ageing resistance of it modified asphalt and conventional engineering properties of bamboo fiber modified asphalt mixtures. Cost analysis and molecular dynamics (MD) simulation attempts were then carried out. Lignin fiber (LF) and polyester fiber (PF) are chosen for comparative study and suggestions for further research were made. The results showed that BF modified bitumen has significant mechanical and oil absorption properties compared to LF and PF modified bitumen. However, its low temperature properties varied with the type of base asphalt. In addition, for bamboo fiber modified asphalt, BF significantly increased its low-temperature cracking resistance and moisture sensitivity, but limited its high-temperature stability, and its fatigue properties need to be further investigated. It is suggested that future research should also improve the dispersion uniformity and interfacial bonding of asphalt with BF, and deeply analyze the modification mechanism of BF on asphalt through micro tests and MD simulation. Through the analysis of economic and environmental benefits, bamboo fiber asphalt mixture can effectively reduce project cost and improve global warming and human hazards, etc. The application of BF in asphalt pavements can enrich the variety of road fibers, which is of great significance to the society, economy, and environment. • The effects of bamboo fiber (BF), lignin fiber (LF) and polyester fiber (PF) on the performance of asphalt were reviewed. • The effects of BF, LF and PF on the performance of asphalt mixture were summarized. • BF modified asphalt pavement has better economic and environmental benefits. • The future research direction of BF in modified asphalt and mixture was proposed. [ABSTRACT FROM AUTHOR]

• Provide solutions to alleviate waste oil pollution. • Recommend the optimal dosage of WEO and WCO to recover performance of aged asphalt. • The basic performance of aged asphalt was improved by addition of WEO and WCO. • Regenerant with WEO and WCO enhanced the RAP utilization. This paper studies the effects that varying amounts of waste cooking oil (WCO) and waste engine oil (WEO) have on the rejuvenation effect of aged asphalt, and the road performance of the 7% compound regenerant to different contents of RAP. The basic performance tests demonstrated the regeneration effect of waste oil, while the microscopic test and chemical composition analysis revealed the regeneration mechanism, after which the road performance was then tested using RAP. Moreover, the study outcome demonstrates that adding appropriate waste oil dosage can effectively increase the conventional physical properties. Furthermore, it was revealed that due to the addition of waste oil supplementing the light components of the aged asphalt, the basic performance of asphalt at different aged degrees can be restored to the standard. Meanwhile, the addition of waste oil will not cause other chemical reactions, but excessive waste oil addition will lead to undesirable reduction in the viscosity of the asphalt, so the recommended waste oil dosage is 1%~4%. In the end, subsequent road performance tests showed that the compound regenerant can achieve 45% RAP application. [ABSTRACT FROM AUTHOR]