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Asphalt Mixtures
Published in M. Rashad Islam, Civil Engineering Materials, 2020
Recycled (or reclaimed) asphalt shingles (RAS) are collected from roof tear-offs, processed, and re-used for pavement. Shingles can contain between 20% and 36% of asphalt, by weight. This asphalt can be used to bind aggregates like the conventional asphalt, or other similar materials. Shingle waste can be collected from two sources. The first source is the manufacturer waste shingles, directly from manufacturers of asphalt shingles. This waste is highly appreciated, as the composition of the material is fairly well known. The other type of waste shingle is known as tear-off from re-roofing or roof removal projects. Literature shows that RAS is beneficial for pavement in terms of increased rutting resistance, reduced cracking, and less compaction effort required (Roque et al. 2018). RAS is also economical and environmentally friendlier, as it saves virgin aggregate, virgin asphalt binder, and reduces landfill demands.
Exterior Enclosure Components
Published in Kathleen Hess-Kosa, Building Materials, 2017
Beyond single as opposed to double thickness, asphalt shingles are organic or fiberglass. Organic asphalt shingles are comprised of asphalt-impregnated organic wood fibers, coated with colored inorganic mineral granules, whereas fiberglass asphalt shingles consist of asphalt-impregnated inorganic fiberglass mats, coated with colored inorganic granules. Organic asphalt shingles are slightly more expensive than inorganic; organic shingles are thicker, heavier, and more durable than inorganic; organic shingles require more asphalt than inorganic; organic shingles have a poor fire rating as compared to inorganic; and organic shingles perform better in cold climates than inorganic.
Mechanical Considerations
Published in Roger Messenger, Homayoon “Amir” Abtahi, Photovoltaic Systems Engineering, 2017
Roger Messenger, Homayoon “Amir” Abtahi
Life-cycle costing is used in economic analyses of renewable energy technologies because these technologies realize their value over time. They are usually characterized by high capital costs and low operating costs. For PV systems on buildings, the combined array-roof configuration is a major contributor to the life-cycle cost. It is important that these configurations last 20–30 years. However, this is not always achieved without unexpected added cost. For example, asphalt shingles often have to be replaced about every 10 years in warm, humid climates. The life-cycle cost analysis should include the added cost of removing and reinstalling the PV array when reroofing.
Rheological multi-scale evaluation of RAP and RAS binders mobilisation in hot mix asphalt
Published in Road Materials and Pavement Design, 2023
Abdeldjalil Daoudi, Anne Dony, Daniel Perraton, Alan Carter
Both for environmental and economic concerns, the use of recycled material in pavement is more and more important for companies and road owners. Reclaimed Asphalt Pavement (RAP) is now a commonly used material. It consists of about 95%wt of aggregates and 5%wt of bituminous binder aged during its life on the road (mechanical + thermal ageing). Post-consumer Recycled Asphalt Shingles (RAS), initially used as roofing materials, especially in North America, can also be reused for road construction in combination with virgin materials. These RAS can contain 25% to 40%wt of bituminous binder combined with fine aggregates and fibres. At the end of their life cycle, they are recovered and shredded to be combined with new materials in the manufacture of Hot Mix Asphalt (HMA). The combined use of RAP and RAS seems to be a good way to reduce costs and reuse non-renewable natural resources (bitumen and aggregates), while reducing energy and emission associated with the extraction and transportation of the new material. However, it is important to consider the different natures of materials, in particular the recycled bitumen, to understand their influence on the final material to ensure good behaviour under traffic and climatic conditions throughout its service life.
The use of the semi-circular bending method to assess the intermediate-temperature fracture toughness of asphalt concrete mixes with reclaimed asphalt shingles
Published in Road Materials and Pavement Design, 2023
In the era of sustainable development, it is necessary to manage resources efficiently, which can be achieved by, among other strategies, increasing the use of recycled materials (Pouranian & Shishehbor, 2019). Of great potential in the production of asphalt mixtures is the use of reclaimed asphalt shingles (RAS), which contain approx. 20–50% of bitumen, as well as mineral sand, load-bearing mat (e.g. glass), fillers or as polypropylene film (as a layer of preventing the asphalt shingles from sticking together). Research on the use of RAS as an HMA ingredient has been conducted for over thirty years (Paulsen et al., 1986). Depending on the origin of RAS, we distinguish between post-production waste, e.g. cuttings from the production of bituminous shingles (MWAS) and used materials stripped from roofing (TOAS). The results of studies show, first of all, the potential to improve the properties of the mixture associated with its operation at high service temperatures, i.e. improved resistance to the formation of permanent deformations (Foxlow et al., 2011; Zhou et al., 2013; Darnell & Bell, 2015; West et al., 2018). On the other hand, mixtures with RAS addition may be more susceptible to the formation of cracks, associated with both low temperatures of pavement use (Zhou et al., 2013) and the phenomenon of its fatigue (Foxlow et al., 2011).
The crossover temperature: significance and application towards engineering balanced recycled binder blends
Published in Road Materials and Pavement Design, 2019
Lorena Garcia Cucalon, Fawaz Kaseer, Edith Arámbula-Mercado, Amy Epps Martin, Nathan Morian, Sara Pournoman, Elie Hajj
The use of reclaimed asphalt pavements (RAP) and recycled asphalt shingles (RAS) in asphalt pavements has become a common practice due to prevailing economic and environmental benefits. RAS can be classified as manufactured waste asphalt shingles (MWAS) or tear-off asphalt shingles (TOAS) depending on their source. Regardless, both types of RAS are heavily oxidised, with TOAS being further aged due to its exposure to the environment in–service. Since recycled binders contained in RAP and RAS materials are extremely oxidised and brittle, the primary concern when employing these materials in asphalt mixtures is susceptibility to cracking.