C&D Recycling Program Recycled Aggregate Introduction This fact sheet is an overview of recycled aggregate, which is produced by crushing concrete, and sometimes asphalt, to reclaim the aggregate. Recycled aggregate can be used for many purposes. The primary market is road base. Benefits of Recycled Aggregate The use of recycled aggregate can save money for local governments and other purchasers, create additional business opportunities, save energy when recycling is done on site, conserve diminishing resources of urban aggregates, and help local governments meet the goal of reducing disposal by 50 percent by the year 2000. What About Recycling Asphalt into New Asphalt Pavement? This fact sheet is NOT about recycling asphalt pavement into new asphalt pavement. See Asphalt Pavement Recycling, CIWMB Pub. #431-95-067. Quantities Source The 1990 waste stream composition data were reported to the California Integrated Waste Management Board (CIWMB) by local governments, in response to the Integrated Waste Management Act of 1989. These reports supplied the following information: Construction and Demolition (C&D) C&D materials made up about 28 percent of California's waste stream, or approximately 11 million tons. Asphalt and Concrete While asphalt and concrete were not reported separately in these data, generation of "inert solid waste," which consists of concrete, asphalt, dirt, brick, and other rubble, was conservatively estimated at 8.2 million tons. The estimated recycling rate for inert solid wastes was 57 percent; the remainder was disposed of. Materials/Definitions Aggregate consists of hard, graduated fragments of inert mineral materials, including sand, gravel, crushed stone, slag, rock dust, or powder. Inert solid waste is concrete, asphalt, dirt, brick, and other rubble. Portland cement concrete (PCC) and asphalt concrete (AC) consist primarily of aggregate. The cement and asphalt serve as binders. Some PCC contains steel reinforcement bars, or "rebar," such as a bridge deck or tilt-up slabs. When a road or structure is demolished, the rebar can often be seen protruding from the broken chunks of PCC. Recycled aggregate comes primarily from PCC and AC from road rehabilitation and maintenance, demolition, and leftover batches of AC and PCC. After processing, the rocks retain bits of cement or asphalt. A roadway is built in several layers: pavement, base, and sometimes subbase. The pavement is the surface layer, and is made of PCC or AC. The base layer supports the pavement, and is made of aggregate base (AB). The subbase layer supports the base and is made of aggregate subbase (ASB). The subbase layer allows more sand, silt and clay than the AB layer; the subbase layer has less strength, but is used because it is more economical when bringing the road up to grade. Equipment The AC and PCC generally arrive at the processor in chunks. Heavy crushing equipment is required to break up the chunks into aggregate. Some equipment is portable and can be set up on site for immediate use of product. A crushing plant may include a hopper to receive the material, a jaw to break it into more manageable pieces, a cone or impact crusher to further reduce its size, a vibrating screen to sort to the required specification, and a conveyor belt with a rotating magnet to remove metal contamination such as rebar.
Recyclers According to the Board's current information, there are approximately 100 producers of recycled aggregate in California. Some receive PCC and/or AC at the plant; others have mobile equipment for in-place recycling. Aggregate recyclers are included in two databases: Construction/Demolition Recyclers Processors & Receivers and Recycled-Content Construction Products, which can be searched at the Board's C&D web site, http://www.ciwmb.ca.gov/ mrt/cnstdemo/default.htm. Hard copies of the lists can be ordered from the CIWMB (see p. 4). Markets Uses Recycled aggregate can be used: In paved roads as aggregate base, aggregate subbase, and shoulders. In gravel roads as surfacing. As base for building foundations. As fill for utility trenches. At this time, the primary market is aggregate base and subbase in road projects. Local Governments Local governments can help promote markets for recycled aggregate because they are large purchasers of aggregate and other road construction products. Some communities are taking steps to promote recycled aggregate, including the following: Los Angeles. In March 1995, the City of Los Angeles passed a motion requiring that road-base in all city projects include "crushed miscellaneous base (CMB) with 100 percent recycled asphalt, concrete, and other inerts, except when site conditions or standards require another specification." (See discussion of CMB under Greenbook Specifications below.) Modesto. The City of Modesto has a purchasing practice for on-site street recycling that includes recycled aggregate. Palo Alto. The City of Palo Alto requires that concrete and asphalt in city projects is recycled. Butte County. Butte County does not require recycling of inerts; however, the local landfill does use clean loads of inerts on site as roadbase or wet weather pads. Specifications Many local jurisdictions use Caltrans specifications. In Southern California, the Greenbook is commonly used. (See Greenbook discussion below.) Where recycled aggregate is allowed, it must also, of course, meet the same grading and quality specifications as virgin aggregate. Caltrans Specifications Procedures Caltrans takes a new specification through three stages: 1. Special Provision (SP). First it is an SP where it is used initially on a number of projects. 2. Standard Special Provision (SSP). After the SP has been used successfully for a period of time, it usually becomes an SSP which means that it is a method approved by Caltrans. 3. Standard Specification. After the SSP has been used successfully for a period of time, then it usually becomes a Standard Specification, and is included in Caltrans Standard Specifications, which is published every four years. The latest edition using English measurements is dated July 1992. A metric edition was published July 1995; all subsequent editions will be metric. The next edition is anticipated in 1998 or 1999. Caltrans Specifications Existing Caltrans' Standard Specifications, July 1995 covers aggregate base and aggregate subbase in Sections 25 and 26. These sections do not mention recycled aggregate. However, Caltrans SSPs do allow "reclaimed asphalt concrete, portland cement concrete, lean concrete base, cement treated base," or "glass" in Class 2 and 3 aggregate base, and also in Class 1, 2, and 3 aggregate subbases. There are two ways to obtain SSPs: Internet. To download SSPs via the Caltrans web site, you must have a computer, a modem, and a web browser to access the Internet. 1. Go to the web site: ftp://trescftp.dot.ca.gov/ pub/specifications/ssps/92- SSPs/Sec_10/22-42/.
2. Select the desired file(s) from among the following: Subbase, "25-010" Base, "26-010," "26-030," "26-080," and "26-100" If a message appears requesting a log-on as anonymous or user, click on cancel. CIWMB. If you don't have access to the Internet, contact Casey Robb at CIWMB (916) 341-6308 to request hard copies or e-mailed copies. Greenbook Specifications What is the Greenbook? The Greenbook, or Standard Specifications for Public Works Construction, is used by the city and county of Los Angeles and 200 other local governments and agencies in the Los Angeles area. Who Publishes It? It is published by the Joint Cooperative Committee of the Southern California Chapter of the American Public Works, and the Southern California Districts of the Associated General Contractors of California. How Often? It is updated and republished every three years. Supplements are published yearly. Where Can I Get It? The 1997 Greenbook includes both English and metric units, and is available for $49.95 through: BNI Building News 1612 S. Clementine St. Anaheim, CA 92802 (714) 517-0970. Aggregate Base Specifications. In Section 200-2, "Untreated Base Materials," the Greenbook includes four categories of aggregate base that are of interest here: 1. Crushed Aggregate Base (CAB) does NOT include recycled aggregate. CAB may sometimes be specified where recycled base (CMB or PMB) would also meet requirements. 2. Crushed Miscellaneous Base (CMB) allows recycled aggregate. The Greenbook states that CMB "shall consist of broken and crushed AC or PCC and may contain crushed aggregate base or other rock." 3. Processed Miscellaneous Base (PMB) also allows recycled aggregate. The Greenbook states that PMB "shall consist of broken or crushed AC, PCC, railroad ballast, glass, crushed rock, rock dust, or natural material." 4. Select Subbase is the Greenbook 's only aggregate subbase category. It allows recycled aggregate. Siting Setting up a new concrete and asphalt recycling plant requires certain State and local permits, such as air and water, and zoning. Where Can I Get Help? Businesses starting or expanding into recycling activities may get financial, technical, marketing, business and permitting assistance from the "R-Team" at CIWMB, at (916) 341-6526. Air Permits The local air districts may be concerned about nuisance odors and various emissions, and may require processors to spray materials with water to control dust. Locate your local air district by calling the Air Resources Board at (916) 322-2990 or by checking their web site at http://arbis.arb.ca.gov/capcoa/roster.htm. Water Permits The Regional Water Quality Control Board may need to permit the facility depending on feedstock and location. Look up your regional board in a local phone book under State Government, Water Quality Control Board or check their web site at http://www.swrcb.ca.gov/loc_link.htm. Solid Waste Permits The CIWMB is currently developing a tiered permitting system for solid waste facilities. However, processors that accept segregated C&D debris should not require a solid waste facilities permit. Contact your Local Enforcement Agency (LEA) for updates. To find out who the LEA is for the project area, call the CIWMB LEA/EA Branch at (916) 341-6333 or check the web site at http://www/ciwmb.ca.gov/pe/lea/directry.htm. Related Organizations Aggregate Producers of Northern California 400 Capitol Mall, Suite 900 (916) 443-5353
Central Valley Rock, Sand, and Gravel P. O. Box 1464 Southern California Rock Producers P. O. Box 40 South Pasadena, CA 91030 (818) 441-3107 San Diego County Rock Products 2831 Camino Del Rio South, Suite 110 San Diego, CA 92108 (619) 260-8316 American Public Works 2345 Grand, Suite 500 Kansas City, MO 64105 (816) 472-6100 California Mining 1 Capitol Mall, Suite 220 (916) 447-1977 (represents mining companies, including some aggregate) National Aggregates 900 Spring St. Silver Springs, MD 20910 (301) 587-1400 Department of Conservation Division of Mines and Geology 801 K St. (916) 445-5716 Los Banos, CA 93635 (209) 826-5955 You can view, print, or download most publications, and search the databases. Publications Free CIWMB Publications CIWMB has published a series of fact sheets, case studies, and resource lists on construction and demolition recycling. CIWMB publications can be obtained in two ways: Mail. To order through the mail, call the CIWMB Recycling Hotline (800) 553-2962, or (916) 341-6308 from outside California. To find out what is available, request the four-page summary of the C&D program and publications, Construction & Demolition Recycling Program (Pub #431-97- 030). Internet. Visit the CIWMB Internet web site at http://www.ciwmb.ca.gov. To locate the C&D page, select Waste Management Programs and Construction & Demolition Debris Recycling.
Related CIWMB Publications C&D Recyclers Processors & Receivers. A 10-page list of ~500 sites in California that receive construction and/or demolition materials for recycling or reuse, including concrete, asphalt and brick. (Pub. #431-96-017) Recycled-Content Construction Products. An 8-page list of ~450 manufacturers of recycled construction products sold in California, including aggregate. (Pub. #431-96-018) Asphalt Roofing Shingles in Aggregate Base. A 2-page overview of recycling ground asphalt roofing shingles into aggregate base. (Pub. #431-97-032) Resource Guide for Recycling-Based Businesses. A 57-page directory of information from the public and private sectors, including business development, technical, financial and feedstock assistance. (Pub. #412-97-028) Market Status Report: Recycled Inerts (October 1996). An 11-page report discussing recycled aggregate, asphalt pavement, asphalt roofing shingles, and drywall. (Pub #431-96-063) Free Directory of Construction Industry The Blue Book Building & Construction PO Box 500 Jefferson Valley, NY 10535-0500 (800) 431-2584 (916) 485-3832 (Sacramento rep) Web site: www.thebluebook.com Free Magazine Subscription C&D Debris Recycling Intertech Publishing 9800 Metcalf Overland Park, Kansas 66212 (800) 441-0294 Reports A Study of the Use of Recycled Paving Material, Report to Congress as specified in the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA), Report No. FHWA-RD-93-147, EPA/600/R-93/095. CIWMB Contact For more information about recycled aggregate, contact CIWMB at (916) 341-6308 or by e-mail at crobb@ciwmb.ca.gov. Publication #431-95-052 Revised April 1998 The Integrated Waste Management Board (IWMB) does not discriminate on the basis of disability in access to its programs. IWMB publications are available in accessible formats upon request by calling the Public Affairs Office at (916) 341-6300. Persons with hearing impairments can reach the IWMB through the California Relay Service, 1-800-735-2929.