Preliminary Study on New Alternative Binders through Re-Refined Engine Oil Bottoms (REOBs) and Industrial By-Product Additives

Abstract

Recent studies have worked towards addressing environmental issues such as global warming and greenhouse gas emissions due to the increasing awareness of the depletion of natural resources. The asphalt industry is seeking to implement measures to reduce its carbon footprint and to promote sustainable operations. The reuse of several wastes and by-products is an example of a more eco-friendly activity that fulfils the circular economy principle. Among all possible solutions, the road pavement sector encourages, on one hand, the use of recycled materials as a partial replacement of the virgin lithic skeleton; on the other hand, it promotes the use of recycled materials to substituting for a portion of the petroleum bituminous binder. This study aims to use Re-refined Engine Oil Bottoms (REOBs) as a main substitute and additives from various industrial by-products as a full replacement for virgin bitumen, producing high-performing alternative binders. The REOBs have been improved by utilizing additives in an attempt to improve their specific properties and thus to bridge the gap between REOBs and traditional bituminous binders. An even larger amount of virgin and non-renewable resources can be saved using these new potential alternative binders together with the RAP aggregates. Thus, the reduction in the use of virgin materials is applied at the binder and the asphalt mixture levels. Rheological, spectroscopic, thermogravimetric, and mechanical analysis were used to characterize the properties, composition, and characteristics of the REOBs, REOB-modified binders, and asphalt mixes. Thanks to the rheological investigations of possible alternative binders, 18 blends were selected, since they behaved like an SBS-modified bitumen, and then they were used for producing the corresponding asphalt mixtures. The preliminary mechanical analysis of the asphalt mixtures shows that six mixes have promising responses in terms of stiffness, tensile resistance, and water susceptibility. Nevertheless, the high variability of recycled materials and by-products has to be taken into consideration during the definition of alternative binders and recycled asphalt mixtures. In fact, this study highlights the crucial effects of the chemical composition of the constituents and their compatibility on the behaviour of the final product. This preliminary study represents a first attempt to define alternative binders, which can be used in combination with recycled aggregates for producing more sustainable road materials. However, further analysis is necessary in order to assess the durability and the ageing tendency of the materials.

Development and Evaluation of Vegetable Resin Bio-Binders as Technological Alternatives to Bitumen

“…In contrast, the ITS values were very high (2.28 MPa) in comparison to the ones obtained in this investigation. Porto et al [32] obtained ITS values ranging between 0.8 and 1.1 MPa when considering VR-based bio-binders mixed with 100% RAP, which are comparable to those achieved by the mixture "0.35O/R-4%SBS"; moreover, it must be considered that the presence of RAP usually tends to stiffen the mixture, supporting the findings of the present investigation. Overall, the results may be considered promising and warrant further investigations.…”

“…Espinosa et al [28] noted an increase in the value of the complex modulus, G*, at high frequencies (low temperatures) compared to a traditional bitumen with a penetration grade of 30/45. Similarly, in DTR tests conducted in the same range of temperatures (25-100 • C) by Porto et al [32], blends containing VR exhibited a prevalence of G ′ over G ′′ at intermediate temperatures and up to 50-60…”

Circular Economy Approaches in the Palm Oil Industry: Enhancing Profitability through Waste Reduction and Product Diversification

“…Anaerobic digestion technology has revolutionized the way palm oil mills manage POME, turning it into biogas and contributing to a more sustainable energy landscape [134,135]. The extraction of bioactive compounds from palm oil and its by-products has paved the way for the creation of high-value functional ingredients, while biobased chemicals and green cosmetics have emerged as sustainable alternatives in various industries [136][137][138][139][140][141].…”

The efficiency of bio-char as bitumen modifier

“…In recent years, the increased interest towards natural resources, that can emulate well known properties of synthetic chemical molecules, strongly influenced the scientific research. This goal has driven the research in the direction of reusing of raw materials and an enhancement of waste products [ [1] , [2] , [3] , [4] , [5] , [6] ]. In this perspective, the design of highly performing road pavements allows an extension of the useful life of the asphalt with a consequent impact in environmental and economic terms [ [7] , [8] , [9] ].…”