Ellie H. Fini

Synthesis and Characterization of Biomodified Rubber Asphalt: Sustainable Waste Management Solution for Scrap Tire and Swine Manure

This paper investigates the feasibility of the application of scrap tire and swine manure to produce a sustainable alternative for bituminous asphalt used in pavement construction. Biobinder is produced from swine manure by using a thermochemical conversion process; biobinder is then blended with crumb rubber and asphalt binder (PG 64-22) to produce biomodified rubber (BMR) asphalt. In addition to offering a renewable alternative for petroleum-based binder, BMR can be a hybrid environmental solution for the management of swine manure and scrap tire. To study the merit of application of BMR in the asphalt industry, this paper compares the rheological properties of BMR with a crumb rubber–modified (CRM) binder commonly being used in the United States. The authors found that BMR has comparable properties with the CRM binder. In addition, the authors found that the introduction of the biobinder to the CRM binder was beneficial in improving the low temperature property of the CRM binder while also reducing the CRM binder’s overall viscosity. In turn, this would allow for lower mixing and compaction temperatures of CRM asphalt while alleviating crumb rubber’s stiffening effect and enhancing the CRM asphalt’s pumpability. A lower mixing and compaction temperature will reduce the greenhouse gas emission during application of the CRM binder in pavement construction.

Effect of introduction of furfural on asphalt binder ageing characteristics

Asphalt oxidative ageing and excessive hardening are known causes of premature pavement cracking. Asphalt ageing occurs mainly due to the oxidation of certain functional groups in asphalt as well as the loss of the maltene phase disturbing colloidal stability and increasing micellisation concentration. This in turn can cause large non-soluble asphaltene aggregates which are typically suspended in the maltene solution and are stabilised by resin molecules to flocculate. Flocculation can cause the asphalt to become stiffer and more brittle. It should be noted that excessive hardening and brittleness of asphalt caused by oxidation during pavement production and service life increase the susceptibility of asphalt pavements to cracking. Therefore, reducing the extent of asphalt oxidation could increase pavement service life. Therefore, it is imperative to reduce/delay asphalt oxidation in asphalt binder. There have been several studies on delaying asphalt oxidation by introducing modifiers and anti-ageing additives. Furfural, an organic compound derived from a variety of agricultural by-products, has been shown to be a promising modifier for petroleum asphalt binders used in asphalt pavement. Accordingly, this paper investigates the effect of introducing furfural as an antioxidant for asphalt by evaluating the extent of oxidation ageing in asphalt specimens modified by 1%, 2% and 5% furfural. To do so, furfural was introduced to asphalt and the level of change in physiochemical and rheological properties of asphalt after specimens were exposed to short- and long-term ageing was examined. Accordingly, performance characteristics of the base asphalt were compared with those of furfural-modified asphalts using a rotational viscometer, Fourier transform infrared spectroscopy and a dynamic shear rheometer to evaluate the rheological properties of asphalt modified with furfural at different percentages. The study results showed that the addition of furfural helped reduce the extent of oxidative ageing while enhancing high-temperature performance of asphalt binder. Specifically, it was found that the 2% furfural modification had the lowest ageing index after ageing, indicating an improvement in binder oxidative ageing.

Highway and Transportation Implications on Environmental Sustainability: Urban Planning, Construction, and Operation Counter Measures

This paper addresses the alarming consequences of high emission rates of greenhouse gases and the significant transportation contribution. It outlines pavement construction impacts on the urban setting and environment. Urban planning options to reduce congestion are explored, including more reliance on public transportation to make it more affordable and attractive for commuters. Furthermore, encouraging environmentally friendly modes of transport, such as walking and bicycling, is essential. Finally, including carbon tax to encourage the transportation sector to promote green technology and low carbon footprint products is another viable consideration.