Recycled Materials and Byproducts in Highway Applications—Manufacturing and Construction Byproducts, Volume 8 (2013) / Chapter Skim
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Pages 27-45
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From page 27... ...
27 From the late 1800s to the 1970s roofing shingles were manufactured by saturating a thick organic mat such as cotton, waste paper, and wood fibers with asphalt and topped with protective stone coating (Seattle Roof Broker 2010; Figure 9)
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28 were shredded by large wood chippers with 500 hp, which produced about 50 to 75 tons of RAS per hour. To ensure that the RAS met the ½ inch minus particles size, the material needed to pass through the shredder a second time (Figure 10)
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29 agreed with previously reported data. Newly manufactured fiberglass RAS had a mat content (2%)
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30 engineering properties will depend on the amount, size, and application for the RAS. environMenTAlly relATed properTies There are several possible exposure pathways for RAS contaminates to the environment that are grinding (e.g., inhalation)
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31 shingles. The DNR stated that landfills "are prohibited from accepting any shingle wastes that will be crushed, broken, or ground on-site per federal NESHAP regulations.
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32 between $0.50 and $1.00 per ton of HMA (typical non-RAS HMA cost $30/ton in Minnesota) , which translated into a savings of between 1.5% and 3.3% in cost.
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33 Question: Manufacturing or Misc. Construction Byproducts: Is your state using, or has ever used, these byproducts in highway applications?
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34 shingle, which was attributed to the RAS being easier to compact and the filler effect from the RAS. The optimum asphalt content was reduced by 0.5% asphalt at 1% of shingle content.
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35 State Comment AL Roofing shingles (manufacturing waste) is routinely used in HMA.
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36 Mix Percentage Material Source RAP Mix 42 78M Vulcan Materials, Skippers, Va. 10 Fine RAP Rose Brothers, Murfreesboro, N.C.
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37 After Maupin (2008)
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38 TABlE 52 CHANGE IN PG GRADE REPORTED IN OHIO AND MINNESOTA RESEARCH Mixture RAP, % RAS, % Change in High Temp Grade Change in Low Temp Grade Resulting PG Grade Ohio DOT Study 10 5 (tear-offs) 0 0 -- 20 5 (tear-offs)
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From page 39... ...
39 study included two sizes of ground RAS: maximum size of the 75 mm and 40% passing the 4.75 mm, 100% passing the 4.75 mm sieve. The five types of aggregates used were crushed limestone, crushed natural gravel with 72% crushed particles, and three recycled concrete aggregates (RCA)
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40 of shingle significantly increased the time needed for a given height of capillary rise. After 60 min, the larger the shingle size the slower the rise.
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41 7. limit lighter material such as paper, plastic, and wood to a maximum of 1.5%, by weight, of the stockpiled RAS as determined on material retained on the 4.75 mm (No.
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42 Where: Fc = initial estimate of percentage of asphalt in blended mix; Pvav = design binder content of virgin HMA without RAS; and Pvar = design binder content of HMA with RAS. The practice noted that this estimate will result in an overestimate of the critical design temperature of the virgin asphalt.
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43 the specification from "job-by-job approval" to "use unless explicitly prohibited" significantly increased the use of shingle byproducts. Once contractors started using RAS, the higher RAS binder percentage in the total binder resulted in premature cracking of one project, hence the 2006 amendment.
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44 suMMAry of roofing shingle inforMATion list of candidate byproducts The list of the most commonly researched and used byproducts included: • Roofing manufacturer, • Tear-off shingles, and • Built-up roofing. Test procedures The test methods found in the literature and survey responses are shown in Table 58.
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45 design Adaptations The following points needed to be considered during the design processes: • Any sand added to the RAS during grinding needed to be considered in mix designs. • Moisture contents of RAS stockpiles needed to be accounted for when used to stabilize soils.
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