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Bayesian economic analyses of including reclaimed asphalt pavements in flexible pavement rehabilitation
Published in John Harvey, Imad L. Al-Qadi, Hasan Ozer, Gerardo Flintsch, Pavement, Roadway, and Bridge Life Cycle Assessment 2020, 2020
Hongren Gong, Miaomiao Zhang, Wei Hu, Baoshan Huang*
Recycling used asphalt pavement materials into new or rehabilitative pavement construction activities have been gaining ever-growing efforts for both of its economic and environmental benefits. Enormous laboratory studies have been performed to investigate the short-term and long-term performance of adding reclaimed asphalt pavement (RAP) into new materials, developing new mixture design methods in considering the impacts of the aged binder in the RAP on the resulting mixtures, examine the blending and mixing status of the aged and virgin binder using both macro and micro techniques (Gong et al., 2018; Huang et al., 2005; Shu et al., 2012). Extensive studies have been focusing on evaluating the field performance of the asphalt mixtures containing RAP along with other techniques in promoting more environmental advantages (Aurangzeb & Al-Qadi, 2014; Shu et al., 2012).
Sustainability in Materials
Published in M. Rashad Islam, Civil Engineering Materials, 2020
Asphalt material is typically produced by removing the lighter hydrocarbon molecules through a combination of vacuum and heat, or by mixing with a solvent, such as propane. The source of crude oil can have a significant effect on the energy and environmental impact of a specific asphalt material, as the processes needed to extract, process, transport, and refine it to produce asphalt material, and other products vary with the source. All these steps are costly and have social impacts. Although asphalt is used primarily in roadways and parking lots, the volume of other materials used for these applications in the United States is still great. For example, the United States used approximately 130 million barrels (23 million tons) of asphalt binder and road oil in 2011, costing $7.7 billion (EIA 2011). The value of asphalt paving mixtures produced in the United States was estimated at $11.5 billion in 2007 (United States Census Bureau 2007a).
Asphalt Equipment
Published in John E. Schaufelberger, Giovanni C. Migliaccio, Construction Equipment Management, 2019
John E. Schaufelberger, Giovanni C. Migliaccio
Asphalt pavements are made by mixing asphalt with aggregate, spreading the mixture over the surface to be paved, compacting the mixture to the desired density, and finishing the pavement surface. Once the subgrade and base have been placed and compacted, the base is primed with a coat of liquid asphalt and allowed to cure for about 24 hours. The application rate generally is between 0.1 and 0.5 gallons per square yard. The purpose of this prime coat is to seal the surface of the base and provide a bond between the base and the pavement. Once the prime coat has cured, plant mix is transported to the construction site in trucks that dump the hot mixture into an asphalt paving machine that spreads the mixture across the surface to be paved, provides an initial compaction, and grades the surface. The paving machine is followed immediately by heavy smooth steel-drum or pneumatic-tire compactors to compact the pavement mix to the desired density before it cools. After the pavement has been compacted, it is finished with a smooth steel-drum compactor to provide a smooth wearing surface. Mixed-in-place asphalt pavement is mixed either with graders or rotary mixers. Once the desired mix has been achieved, the mix is spread with a grader. Smooth steel-drum or pneumatic-tire compactors are used to compact the mix, and a smooth steel-drum compactor is used to finish the pavement.
Physico-chemical and mechanical properties of asphalt binders blended with waste bio-shell powder
Published in International Journal of Pavement Engineering, 2023
Yuchen Guo, Guanyu Ji, Xuancang Wang, Beisi Tian, Yi Zhang
Asphalt is an excellent viscoelastic material and an important raw material in highway engineering, it is widely used in pavement construction worldwide (Behera et al. 2021). However, the production process consumes large amounts of energy such as coal, electricity and gasoline and produces large amounts of greenhouse gases such as methane and carbon dioxide (Ma et al. 2021, Ma et al. 2022). The European Asphalt Association publishes information on the production cycle of asphalt, which shows that the production of 1 tonne of asphalt releases 182.12 kg of greenhouse gases such as carbon dioxide (Eurobitumen 2020). And asphalt is a non-renewable resource, and excessive consumption will cause many environmental problems (Zahoor et al. 2021). Road industry researchers adhere to concepts of energy saving, environmental protection, and renewable and sustainable development, actively seeking new materials that can replace asphalt bonding materials to ensure sustainable road project development (Dong et al. 2020, Nizamuddin et al. 2022). Therefore, developing renewable asphalt modifiers with good cost-effectiveness is urgently required.
Waste chicken fat oil as a biomass regenerator to restore the performance of aged asphalt: rheological properties and regeneration mechanism
Published in Road Materials and Pavement Design, 2023
Ke Shi, Zhen Fu, Rui-meng Song, Feng-liang Liu, Feng Ma, Jia-sheng Dai
Asphalt pavement is of paramount importance for the social and economic development of the world. However, pavement construction requires high energy demands, consumes large amounts of raw materials (asphalt binder and aggregate), and is responsible for a high level of greenhouse gas (GHG) emissions (Ma et al., 2021; Xu et al., 2020). Furthermore, asphalt binder is extracted from crude oil, which is a nonrenewable resource (Zhao et al., 2021). Affected by the increased costs of extraction and war, crude oil faces a long-term shortage. Similarly, aggregate faces a shortage over the long term. Additionally, many countries strictly control the extraction of aggregates to protect the environment, which further aggravates the problem of aggregate shortages. Nevertheless, despite dire resource shortages, the amount of waste asphalt mixture is increasing year by year. Affected by asphalt aging and traffic load, asphalt pavement is prone to cracking and other problems after long periods of use. At present, highways are being overhauled, resulting in large quantities of waste asphalt mixtures. Waste asphalt mixtures have a highly negative effect on the environment and constitute a waste of resources. As a result, in the context of sustainable development, concern has arisen regarding the application of new technologies to minimise the adverse impact of waste asphalt mixtures on the environment (Ding, 2008). Thus, researchers have studied and designed processes for recycling waste materials, and reclaimed asphalt pavement (RAP) technology has been developed (Plati, 2019; Wei et al., 2020).
Asphalt pavement coated by hot-pressed hydrated lime
Published in International Journal of Pavement Engineering, 2021
Huang Man, Hongliang Zhang, Liu Jifa
Moreover, the lifetime of HL coating (about 7 years) (Emery et al.2014) is longer than that of heat-reflective coating (about 3–6 months) (Feng 2010, Cao et al.2016). High-temperature weather generally lasts for about three months in most areas. Consequently, the heat-reflective coating will be coated once per year. At present, the lifetime of asphalt pavement is about 15 years. Therefore, the heat-reflective coating would be required 15 times during the lifetime of asphalt pavement. HL coating can only be coated immediately after the construction of asphalt pavement, and therefore, it only requires coating once within the entire life-cycle of the asphalt pavement due to the involved construction technology. After HL coating is worn out, the hot-reflective coating might be considered to be applied heat-reflective coating on the surface of asphalt pavement to reduce the temperature of asphalt pavement continuously. So, the cost difference between HL and the heat-reflective coating is mainly evident within the first seven years when HL coating has not been worn out. During the remaining lifetime (8 years) of both asphalt pavement types, the heat-reflective coating will be coated eight times, and the cost remains the same.