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Applying foamed warm-mix asphalt in pavement has attracted great attention, but its effects on asphalt mastic are not clear. This research investigated and compared the performance characterization of asphalt mastic prepared by foamed and unfoamed binders. The functional group information, thermal behavior, and rheological characteristics were explored using a series of experiments. Results show that both foamed and unfoamed asphalt mastics have similar function groups, which indicates that foaming process does not change the infrared absorption structure of asphalt mastic. Besides, asphalt foaming seems not affect the thermal stability of mastic, although some foaming water is still present. The high- and low-temperature performances of asphalt mastic were slight weaken by foaming water, but the effect is not significant based on the analysis of variance. The asphalt–aggregate interaction of asphalt mastic is significantly improved by the foaming behavior. This study concluded that foamed asphalt mastic could achieve the similar performances with unfoamed asphalt mastic. [ABSTRACT FROM AUTHOR]

The aim of this research is to evaluate the effect of polyphosphoric acid (PPA) on the mechanical performance of styrene–butadiene–styrene (SBS) and styrene–butadiene–rubber (SBR) modified asphalt. Conventional properties, multiple stress creep recovery (MSCR), bending beam rheometer (BBR), and linear amplitude sweep (LAS) tests were conducted to evaluate the performance characteristics of asphalt at different PPA inclusions. Gel‐permeation chromatography (GPC), saturates, aromatics, resins, and asphaltenes (SARA), and Fourier transform infrared (FTIR) were carried to reveal the molecular weight, component and infrared spectra of asphalt. Results showed that PPA hardened the asphalt, improved the rutting and fatigue performances of polymer modified asphalt (PMA) binder, but weakened the anti‐cracking performances. Besides, storage stability had a significant improvement as the addition of PPA. The addition of PPA brought more macromolecules into asphalt and led to more high‐average molecular weight compounds. Furthermore, PPA changed four component ratios of asphalt. Both PMA with or without PPA have similar absorption peaks. This may be due to absorption peak of PMA covered the changes in PPA modification process as the low content of PPA. 0.8% dosage of PPA may be considered optimum for composite modified binder combining the above experimental results for this binder source. [ABSTRACT FROM AUTHOR]

The objective of this research is to investigate the physiochemical and rheological properties of waste cooking oil (WCO)/styrene‐b‐butadiene‐b‐styrene/ethylene vinyl acetate (SBS/EVA) composite modified asphalt. A petroleum asphalt composite modified with SBS/EVA and oil/SBS/EVA were prepared to undergo the physical, rheological, and microscopic experiments. Comparing these tests results with the properties of unmodified petroleum asphalt, SBS and EVA cause an improvement in pavement performance, but weaken the storage stability. Although the high‐temperature performance undermined by the addition of WCO, the thermal stability, fatigue property, and low temperature crack resistance improved obviously. In addition, WCO mainly composed by low‐weight components, and these can supplement the light components in the polymer‐modified asphalt. EVA could increase the percentage of large molecular size of asphalt, while WCO relieves this trend. The reactions between WCO and these polymers (SBS and EVA) are physical reactions. Atomic force microscopy morphology results reflect that SBS and EVA increase the surface complexity and roughness, and WCO makes the asphalt surface smooth. This indicates WCO increases the dispersion of polymers in asphalt. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48828. [ABSTRACT FROM AUTHOR]

In order to analyze the rationality of evaluation indexes HI1, HI2, HI3, HI4 and HI5 based on rheological properties for self-healing performance of asphalt, DSR (dynamic shear rheometer) is used to test the relationship between the complex modulus and loading times of virgin asphalt, SBS modified asphalt and rubber modified asphalt. Based on four-point bending fatigue test, the fatigue-self-healing properties of virgin asphalt mixture, SBS modified asphalt mixture and rubber modified asphalt mixture are studied. The results demonstrate that evaluate the self-healing performance of asphalt with different indicators may obtain different results, the order of self-healing ability of virgin asphalt, SBS modified asphalt and rubber modified asphalt is inconsistent, and the evaluation result of HI5 index on self-healing ability of three asphalts is consistent with mixtures, the self-healing ability of rubber modified asphalt and SBS modified asphalt is better than virgin asphalt obviously. [ABSTRACT FROM AUTHOR]

The waste engine oil (WEO) on the rheological characteristics of asphalt were studied. Two types of asphalt binders and five WEO contents (2%, 4%, 6%, 8%, and 10% wt. %) were selected to prepare WEO modified asphalt samples. Results indicated that both WEO modified asphalt had lower elastic portion, thermal susceptibility, Zero shear viscosity (ZSV), and rutting resistance, but had higher fatigue resistance and temperature sensitivity. Moreover, the effect of waste engine oil on pure asphalt is more significant than SBS modified asphalt. [ABSTRACT FROM PUBLISHER]

Although foamed warm mix asphalt (FWMA) offers several benefits, concerns exist regarding the potential moisture damage that can be produced within it. Boiling water tests, the surface free energy (SFE), the binder bond strength (BBS), and atomic force microscopy (AFM) morphologies are all used to analyse the moisture damage of asphalt. These methods were evaluated and compared in this study. The results indicate that some residual moisture remains trapped in asphalt after foaming and that the foaming states for base asphalt and SBS modified asphalt attain stability after 6 min and 15 min, respectively. Boiling water tests are unsuitable for evaluating the adhesion of FWMA. SFE and BBS tests demonstrated that the residual foaming water undermines the bond strength of FWMA by reducing the cohesion energy. The Scanning Electron Microscope (SEM) and AFM methods were used to identify differences between morphologies by investigating the various foaming water contents. The results of SFE, BBS, and AFM morphologies were observed to be in agreement. Although cohesive failure modes were observed in the BBS experiment, foaming water aggravates the adhesion failure and causes moisture damage owing to the participation of external water. Furthermore, the results indicate that less water damage resistance is associated with substantial amounts of foaming water. These findings provide a clearer understanding of the moisture susceptibility of FWMA. [ABSTRACT FROM AUTHOR]

• The performances of foamed warm mix binders and mixtures containing reclaimed asphalt pavements were evaluated. • Foamed asphalt and mixture have a better low- temperature performances and fatigue life than those of unfoamed ones at the same RAP content, but have a worse high-temperature performances and water stability. • Asphalt foaming relieves the effects of RAP on asphalt and mixture performance. • Foamed asphalt mixture contains RAP could meet the standard requirements when RAP does not exceed 30%. Concerns exist regarding whether residual foaming water will be unfavourable for the performance of asphalt and mixtures when foamed warm mix asphalt (FWMA) binders are combined with reclaimed asphalt pavement (RAP). A series of experimental methods was utilised to evaluate the performance of FWMA–RAP binders and mixtures. It was found that the FWMA–RAP binder performance was consistent with that of the mixtures. Foamed asphalts and mixtures exhibited better low-temperature performance and had longer fatigue lives than their unfoamed counterparts did at the same RAP content, but exhibited worse high-temperature performance and lower water stability. The RAP content had a significant influence on the asphalt and mixture performances and appeared to aggravate the effect of asphalt foaming. Foamed asphalt mixtures containing RAP were able to satisfy the standard requirements when the RAP content did not exceed 30%. [ABSTRACT FROM AUTHOR]

• The ageing behaviors of WEO-modified asphalt binders were evaluated. • Asphalt binders modified with WEO were aged in RTFOT, PAV and double PAV process. • Conventional test, rheological test, FTIR and AFM were conducted on the asphalt samples at different ageing levels. • WEO could significantly improve the ageing resistance of WEO- modified asphalt. • WEO decreases the "bee-like" structures and reduces the maximum lengths of "bee-like" structures. The aim of this research is to evaluate the ageing behaviour of waste engine oil (WEO)-modified asphalt binders. Conventional properties, rheological characteristics and microscopic features were tested on the aged residues through rolling thin film oven, pressure ageing vessel and double PAV test. Results demonstrate reveal that ageing improves the high temperature performance, reduces the low temperature and fatigue performances of asphalt, while introducing WEO into asphalt significantly improves its ageing resistance. Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) results further reveal that WEO can efficiently reduce the oxygen ageing effect by supplying lightweight components. [ABSTRACT FROM AUTHOR]