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Volatile organic compound (VOC) emissions are becoming an increasingly significant issue because of the increasing demand for bitumen in road engineering. This study attempted to develop a type of fume-suppressed bitumen with good comprehensive performance. Initially, 1, 2, and 3% organic montmorillonite and 2, 3, and 4% waxy warm-mix agents were utilised to modify bitumen. Subsequently, the fume suppression and physical and construction performances of the modified bitumen were evaluated, and the modified bitumen with the best comprehensive performance was determined. On this basis, constant- and variable-temperature heating modes were designed to verify the fuel suppression performance of the modified bitumen thoroughly. Finally, the modification mechanism of modified bitumen was investigated via atomic force microscopy. The results indicate that the modifier had the greatest impact on the ductility of the modified bitumen in terms of its physical performance. Although waxy warm mixed agents increase VOC emissions, organic montmorillonite can inhibit this effect. The modified bitumen, composed of 2% organic montmorillonite and 2% waxy warm mix agent, has the best comprehensive performance, with a 40.6% emission reduction rate under constant temperature heating mode and 46.4–28% range from 200 ℃ to 120 ℃ under another mode. The waxy warm mix agents and organic montmorillonite-modified bitumen developed into continuous and dispersed phase systems, respectively, leading to variations in the modified bitumen's physical performance and VOC emission capacity. In contrast, the composite-modified bitumen exhibited a two-phase structure with the surface morphology of an 'egg tray'. This unique structure enhances the heating surface area and facilitates heat conduction, improving the bitumen performance during construction. [Display omitted] • Consideration was given to the VOC emission reduction effect caused by the decrease in viscosity of bitumen. • The efficacy of fume suppression asphalt was verified in two heating modes. • A fume suppression asphalt with commendable comprehensive performance was designed. [ABSTRACT FROM AUTHOR]

• A laboratory characterization of fully recycled asphalt concretes for utility cuts and potholes repairs is presented. • Two different reclaimed asphalt pavements stockpiles were analysed and characterized. • Chemical additives were used in substitution of virgin bitumen for the production of fully recycled hot asphalt concretes. • The use of chemical additives does no reduce the workability of the fully recycled hot mixtures. • The experimental mixtures performed similar to traditional asphalt concretes. The reuse of recycled materials, such as Reclaimed Asphalt Pavement (RAP), is one of the most widespread and sustainable alternatives to continuous exploitation of raw materials in the road pavements sector. Over the years, numerous studies have been conducted on the use of RAP in the production of Hot Mix Asphalt (HMAs) in different percentages and with several bituminous binders and additives. At the same time, little attention was paid to the possibility of using this recycled material as HMA for small road maintenance interventions. Cold Mix Asphalt (CMA) is still the material widely adopted for potholes repairs and patch pavement rehabilitations, despite its lower performance if compared to HMA. The idea developed in the present research is the possibility of using the hot recycling technology for the production of patch asphalt for potholes and utility cuts repairs. In particular, the focus of the study was the development of an HMA produced with 100% RAP and without the addition of bituminous binders. Thus, three different chemical additives were tested for the experimental recycled HMAs. Promising results have been obtained in the laboratory characterization, showing that the recycled materials can have physical and mechanical performances comparable to HMA produced with virgin aggregates and bitumen. [ABSTRACT FROM AUTHOR]

• Use of RCA in bituminous mixes have several advantages and some disadvantages. • Physical, chemical and microscopic properties of RCA depends upon adhered mortar. • RCA's quantity and quality highly affect the properties of RCA incorporated mixes. • Different methods can be used to improve performance of RCA incorporated mixes. Utilizing Recycled concrete aggregates (RCA) in bituminous mixes contains several environmental and economic benefits however the poor physical properties of RCA in some cases results in inferior mix properties as compared to mixtures comprised of virgin aggregates. Due to these drawbacks, field utilization of RCA in bituminous mixes is very low. This paper presents a detailed review associated with different stages included in the utilization of RCA in bituminous mixes. The paper discusses different stages and treatment methods used to produce RCA. It also talks about RCA's conventional characteristics i.e. physical and chemical and microscopic characteristics and how they affect the performance of RCA incorporated bituminous mix in terms of stability, indirect tensile strength, rutting, fatigue, resilient modulus, moisture damage potential, and low-temperature performance with the help of reviewing available literature. The available approaches for enhancing the RCA's physical properties and the performance of RCA incorporated bituminous mixes are also explored. [ABSTRACT FROM AUTHOR]

• The addition of Maleic anhydride grafted waste leather can greatly improve various properties of asphalt binder. • The storage stability of modified asphalt is greatly enhanced after grafting waste leather with Maleic anhydride. • Chemical reaction occurred between the grafting activated waste leather powder and base asphalt during modification process. The objective of this study is to seek a methodology to recycle the waste leather in an efficient and eco-friendly way. In this study, modified asphalts samples containing 9% and 12% waste leather powder (WL) and Maleic anhydride grafted waste leather (MAH-WL), as well as base asphalt sample, were prepared. In addition, these tests of penetration, softening point, ductility, DSR, MSCR, fluorescence microscope, FTIR and SEM were applied to investigate the conventional physical performance, high-temperature rheological characteristic and storage stability of asphalt samples. The results indicated that under the same content of waste leather powder, grafting activation could reduce the penetration of asphalt and greatly improve the softening point and the ductility. Furthermore, the high-temperature rheological characteristic of MAH-WLMA was improved compared with base asphalt and WLMA. The storage stability of modified asphalt was also greatly enhanced after grafting Maleic anhydride to waste leather. The result of FTIR manifested that chemical reaction was occurred between the grafting activated waste leather powder and base asphalt, while the modification of waste leather without grafting was merely a physical process. Overall, using grafting activated waste leather as a bio-modifier of asphalt is feasible and promising, while some limits do exist. To comprehensively master the modification mechanism and apply MAH-WLMA to practical projects, further experiments need to be conducted. A range of performance of grafting activated waste leather asphalt mixture should also be investigated in the future. [ABSTRACT FROM AUTHOR]

• Two resources of LCAs were applied to prepare the LCAs-MA. • Physical and rheological properties of LCAs-MA were investigated. • LCAs can obviously reduce viscosities and increase the workability of LCAs-MA. • LCAs will not decrease the rutting resistance of asphalt with limited dosages. • LCAs can obviously increase anti-fatigue and anti-crack properties of asphalt. Decreasing the viscosity of asphalt binder is a widely applied and successful mechanism to reduce the construction temperature of asphalt mixture. Depending on this case, the waste rubber and plastic are applied to produce low-temperature construction additives (LCAs), in an attempt to reduce the construction temperature of asphalt mixture. The LCAs modified asphalt (LCAs-MA) were manufactured with different dosage of LCAs at varied temperatures, and it is to determine the manufacturing parameters such as LCAs dosages and blending temperature of LCAs-MA. After this, viscosities of LCAs-MA with various contents of LCAs were tested to investigate the LCAs and its dosage effects in the construction temperature of asphalt mixture. In addition, the physical and rheological properties of asphalt binders were studied as well, which is used to assess the technical performance of LCAs-MA. The content of LCAs-1 and LCAs-2 in the LCAs-MA should be not less than 8.6%–10% and 11.5%−13% respectively. The changing tendency of physical and rheological performance of LCAs-MA indicates that a reduction in the high-temperature performance of LCAs-MA, and a dramatic increase in its low-temperature performance. The failure temperature of asphalt at a G*sinδ Value of 5000 kPa is reduced after addition of LCAs, indicating that LCAs can improve the fatigue crack resistance of asphalt. Comparatively, the same amount of LCAs-1 has a more significant impact on the technical performance of asphalt than LCAs-2. [ABSTRACT FROM AUTHOR]