Market Status Report:
Recycled Inerts

Table of Contents

Preface

I.  Introduction

• Definitions
• Quantities
• Importance
• Primary Members
• Legislation

II.  Current Supply

• Factors Affecting Supply
  Economics
  Quality
  Demolition/Construction Activity

III.  Projected Supply

IV.  Current Demand

• Factors Affecting Demand
  Aggregate Specifications
  Asphalt Specifications
  Quality of Product
  Negative Perception/Lack of Information
  Construction Activity
  Supply of Virgin Inerts

V.  Projected Demand

• Aggregate
• Asphalt
• Asphalt Roofing
• Drywall

VI.  Primary Barriers to Material Supply/Demand

• Caltrans Aggregate Specifications
• Caltrans Asphalt Specifications
• Asphalt Roofing Specifications
• Negative Perception
• Lack of Information
• Unique Industry Costs

VII.  Strategies to Overcome Barriers

• Specifications
• Negative Perception
• Lack of Information
• Unique Industry Costs

VIII.  Summary

• Major Barriers
• Strategies

I. Introduction

This paper addresses California markets for recycled inert wastes. Topics covered include supply, demand, trends, barriers and recommendations to overcome barriers.

Definitions

The term inerts includes concrete, asphalt, asphalt roofing, aggregate, brick, rubble, and soil. Drywall is often included in this category, though it is not technically an inert. Processor, or recycler, is the person or business that crushes or grinds the inerts. This paper focuses on the following inerts:

• Recycled aggregate, made from crushed concrete and asphalt.
• Recycled asphalt, which is asphalt pavement made with a percentage of reclaimed asphalt pavement.
• Asphalt roofing refers to asphalt composition roofing shingles, which is made of asphalt, small­sized aggregate, and roofing felt made of either fiberglass or cellulose.
• Drywall, which consists of a sheet of gypsum covered with paper and used for interior walls.

Quantities

The most current waste characterization numbers come from the 1990 waste stream composition data reported to the California Integrated Waste Management Board (CIWMB) by local governments. Generation of inertsolidwaste was estimated at 8.9 million tons. The recycling rate for this category was 57 percent. The remainder, 43 percent or 3.5 million tons, was disposed of in 1990; this amount comprised 8.8 percent of the waste stream. Asphalt roofing accounts for approximately 1.1 to 2.2 million tons yearly.

New construction drywall waste is estimated to be from 300,000 to over 500,000 tons per year, depending on the amount of new construction.

Importance

Although inerts recycling is one of California's best success stories, there is the potential to increase the rate much further through education and specification changes. Inerts recycling is important for waste reduction goals due to the material's heavy weight. It has good recycling potential because it is durable, it can be stockpiled, it is easy to keep segregated, and it can often be recycled on the same project, thus avoiding transportation costs. Inerts recycling can be very cost-effective in urban areas where most of the feedstock is produced.

Drywall recycling is important because gypsum can produce hydrogen sulfide gas in certain landfills, particularly in a wet climate. Hydrogen sulfide gas is toxic at high concentrations (~1,000 parts per million) and has a foul, rotten egg odor. Drywall is also a major component of construction waste, and can be used for a variety of purposes.

Primary Members

The primary members of the inerts recycling industry are generators/ purchasers (e.g., Caltrans, municipalities, private developers), landfill operators and haulers, processors and contractors, and pertinent regulatory agencies. Farmers are presently the largest purchaser of recycled drywall.

Legislation

Assembly Bill (AB) 1306, which was enacted into law in 1989, required Caltrans to review and modify all bid specifications for paving materials, and base, subbase, and pervious back fill materials to encourage the maximum use of recycled materials. The bill also requires Caltrans to purchase recycled paving materials, base,etc., if the price is competitive. Although Caltrans has developed some paving specifications allowing recycled material, many of these have not been well publicized, and other specifications still prohibit recycled content. Public Resources Code §42700, enacted in 1990, requires the CIWMB to work with Caltrans to review and develop specifications for using recycled materials in pavement products.

The federal Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991 required research on and use of recycled materials in pavement products. However, these requirements have been repealed, eliminating any federal mandates to reuse inerts.

II. Current Supply

Most inerts are currently generated from road construction and private on-site work, in the form of concrete, asphalt, and aggregate. Most road construction is by Caltrans and local public works projects. Private on­site work generates inerts from sidewalks, curbs and gutters, new development adjacent to existing streets, parking lots, building foundations, and concrete walls. Old asphalt roofing is generated mostly from residential roof replacements, while new asphalt roofing is composed of cut offs from manufacturing plants. Drywall is generated at construction and demolition sites, though the construction scrap is cleaner and has more market potential.

Factors Affecting Supply

Supply is primarily affected by economics, quality, and amount of demolition activity or, in the case of drywall, the amount of construction activity.

Economics

Numerous economics factors affect the supply of inerts for recycling:

• Equipment. Processors must modify or purchase equipment, which also may require additional permits and their costs.
• Tipping fees. The average landfill tipping fee in California is $31. A typical recycler's tipping fee ranges from $4 to $12 per ton.
• Transportation costs. The distance to the processor versus to the landfill must be factored in. Hauling costs approximately $60 per hour.
• Labor costs. Additional labor is required to keep inerts separate at the job site, or to separate it at the recycler's.

• Price of product. The reclaimed aggregate or gypsum price will affect the overall economics; a higher purchase price means the tipping fee can be lowered, thus attracting more feedstock. In southern California, virgin aggregate costs $7 to $11 per ton, and recycled aggregate costs $2.50 to $6 per ton. In northern California, virgin aggregate costs $5 to $7 per ton, and recycled aggregate is competitive with virgin. Mined bulk gypsum costs approximately $30 per ton; reclaimed gypsum costs $15 to $20 per ton. 

Quality

If the quality of the feedstock is low, it may be rejected by the processor. The inerts can be contaminated if not properly separated from other materials at the job site. Common contaminants in aggregate base are organics such as wood, grass, and paper; plastic; metals; and brick, though brick may be acceptable and even desirable in aggregate subbase. Drywall can be contaminated with wood and miscellaneous paper; for some uses, the drywall paper is a contaminant, though in agriculture it assists with water absorption.

Demolition drywall can be contaminated with nails, tape, joint compound, and paint, and should be used for non-agricultural purposes only.

Demolition/Construction Activity

The amount of demolition and construction activity affects the supply. Caltrans projects often require large volumes of aggregate. Some stationary recyclers are too small to supply these large quantities at one time. Without adequate space to stockpile, these smaller processors require steady demolition to replenish supply. Earthquakes and military base demolition can create a large supply of excess concrete and asphalt in specific areas. However, if military bases can landfill at no charge, they have no incentive to pay a recycler's tipping fee, and are likely to landfill it or leave it in place. Construction activity increases the supply of leftover concrete and clean drywall scrap.

III.  Projected Supply

The future supply of inerts will be affected by disasters, base closures, local government policies, and landfill tipping fees.

• Disasters, particularly earthquakes, will continue to create a steady supply of inerts.
• By the year 2000, 29 military bases will be closed or "realigned" in California, with a total land area of 116 square miles. The potential for inerts stockpiling from demolition is enormous.
• Local government recycling policies may require more inerts recycling.
• Landfill tipping fees may rise eventually, making recycling more cost-effective from further distances.
• An increased rate of demolition is expected because as cities continue to grow, there will be less available open space in which to build.

IV.  Current Demand

The current demand for reclaimed concrete and asphalt is primarily as aggregate used as base under roads. It is also used under parking lots, driveways, and building foundations, and as pipe trench structural backfill. Concrete and asphalt can also be crushed to 2 to 6 inches and, along with rubble, brick, and dirt, be buried as construction fill material at the job site, such as that used in the recent residential sink hole in San Francisco. The largest demand for reclaimed gypsum from drywall is as a soil amendment or additive.

Primary purchasers of aggregate include Caltrans contractors, local public works agencies, and private developers; while farmers are the primary purchasers of reclaimed gypsum.

Recycled asphalt pavement (15 percent recycled) is also currently used on non-Caltrans projects, primarily in southern California.

Factors Affecting Demand

Demand is primarily affected by specifications, quality of product, negative perception/lack of information, amount of construction activity, and supply of virgin inerts.

Aggregate Specifications

Greenbook

The Greenbook is the common name for the Standard Specifications for Public Works Construction, which is published by southern California chapters of the American Public Works Association and the Associated General Contractors of California. Most municipalities in southern California depend on the Greenbook for roadway specifications. The Greenbook allows crushed asphalt, concrete, and aggregate in its "Crushed Miscellaneous Base" (CMB), "Processed Miscellaneous Base" (PMB), and Select Subbase. However, many contractors habitually specify "Crushed Aggregate Base" (CAB) which does not allow recycled aggregate.

Caltrans

Most municipalities in northern California depend on Caltrans' Standard Specifications, July 1992. In Caltrans ' terminology, aggregate base (AB) is the layer that supports the pavement, and aggregate subbase (ASB) is the layer that supports the AB. The specifications do not mention recycled inerts in Class 2 or 3 AB or in Class 1, 2, or 3 ASB. However, Caltrans ' Standard Special Provisions (SSP) amends these specifications to allow "reclaimed" asphalt and concrete in Class 2 and 3 AB and Class 1, 2, and 3 ASB. SSPs are methods that have been used successfully for a period of time, and are approved by Caltrans for general use. Some purchasers are not aware of this.

Asphalt Specifications

Greenbook

The Greenbook provides specifications for 15 percent recycled asphalt and is widely used in southern California.

Caltrans

There is currently little demand for recycled asphalt in Caltrans projects, as Caltrans is still in the process of developing recycled asphalt specifications.

Most municipalities and private developers in northern California will not use recycled asphalt until Caltrans develops specifications. Even if local governments used other specifications, there is little supply because the asphalt recycling industry requires large volume markets before investing in equipment. However, one company in the East Bay, Gallager & Burke, has purchased a plant and sells 15 percent recycled asphalt to several area agencies, while another company routinely adds 5 percent recycled to all new asphalt.

Quality of Product

Demand for recycled inerts is dependent on the materials' quality. Contaminated inerts might contain clay, metal, brick, or wood. Clean construction drywall contains certain additives from the manufacturing process, such as boron. Boron can be a detriment or a benefit depending on the amount of boron already in the soil and the type of crops being grown.

Negative Perception/Lack of Information

Many city/county engineers are unlikely to specify recycled aggregate base because they are accustomed to virgin materials and lack experience with recycled. Some hear rumors of problems, but are not aware of the success stories. Many farmers already use mined gypsum and are reluctant to switch to reclaimed gypsum for fear of contamination.

Construction Activity

Demand for aggregate and asphalt depends on the amount of construction, particularly roadway construction, which is determined in part by economic cycles, State and local policies, and transportation bond election results.

Supply of Virgin Inerts

Reserves of aggregate are diminishing at quarries that are convenient to urban areas. Some existing quarries have a five- to ten-year projected life, and it is becoming more difficult to permit new quarries near urban areas.

V.  Projected Demand

Demand will probably increase for recycled aggregate, asphalt, and asphalt roofing by Caltrans and municipal projects, as discussed below.

Aggregate

Municipalities are expected to use more recycled aggregate as they learn of Caltrans' SSPs and gain confidence with local processors. The Board has begun a variety of efforts to promote the SSPs and the use of recycled aggregate, including the publication of two fact sheets, Recycled Aggregate and Asphalt Pavement Recycling, which are being distributed to local government recycling coordinators. Other outreach appears beneficial.

Asphalt

Recycled asphalt is expected to increase on Caltrans and local road projects after Caltrans completes test projects. Caltrans is presently testing several processes for asphalt recycling. Specifications for two processes, "hot recycling at a central plant" (25-50 percent recycled), and "cold, in-place" (100 percent recycled). These specifications were supposed to be ready by mid-1996 in the form of SSPs, according to Caltrans. They are also testing recycled asphalt from multisource stockpiles (15 percent recycled), a microwave process (70 percent recycled), and a "hot, in-place" process (100 percent recycled).

Asphalt Roofing

Asphalt roofing can be used to produce a road-patch material, and can be ground and added to hot-mix asphalt (primarily new shingles) or aggregate base (primarily old shingles). Asphalt roofing has been recycled in numerous projects outside California, including New Jersey, Minnesota, Ontario, North Carolina and Massachusetts. There are currently no recyclers of asphalt roofing in California to Board staff's knowledge; however, there is growing interest. In the spring of 1996, Caltrans tested the use of old asphalt roofing as 10 percent of Class 2 aggregate base, with favorable results. Board staff will be discussing with Caltrans the possibility of a pilot project. A prospective recycler claims that asphalt roofing will lower the cost of aggregate base, which will increase the demand for old asphalt roofing.

Drywall

Recycled drywall prices compete favorably with virgin gypsum. With additional studies to verify its purity, more farmers should be willing to purchase reclaimed gypsum. 

VI.  Primary Barriers to Material Supply/Demand

The primary barriers to supply and demand are specifications, negative perception/lack of information, and unique industry costs.

Caltrans Aggregate Specifications

As noted earlier, Caltrans has developed Standard Special Provisions (SSP) that allow recycled asphalt and concrete in Class 2 and 3 AB and Class 1, 2, and 3 ASB. However, they are not included in Caltrans' Standard Specifications, July 1992, the book that contractors and city/county engineers routinely use.

Caltrans Asphalt Specifications

Caltrans' Standard Specifications, July 1992 does not mention reclaimed asphalt for use in asphalt pavement. Caltrans is presently testing five processes of asphalt recycling. Development of these specifications is long overdue, and has been repeatedly postponed due to Caltrans' other priorities.

Asphalt Roofing Specifications

Neither the Greenbook, Caltrans' Standard Specifications, July 1992, nor Caltrans' SSPs mention ground asphalt roofing shingles in aggregate base, sub-base, or asphalt.

Negative Perception

Some purchasers, particularly city and county engineers, are leery of using recycled inerts because they assume their quality is inferior to virgin. Some local governments have long-standing relationships with quarries, and no longer even test the products delivered to the work site. They are reluctant to change to an unknown product. Some engineers have had, or heard of, bad experiences with recycled inerts, so refuse to specify or allow them on their projects.

Lack of Information

Aggregate

The inerts recycling industry is multi-faceted, and communication is often not as effective as it could be. As noted earlier, Caltrans has developed Standard Special Provisions (SSP) that specifically allow recycled asphalt and concrete in Class 2 and 3 AB and Class 1, 2, and 3 ASB. These SSPs, however, are not in the standard specification book, and therefore not as easily accessible. Recycled inerts are relatively new products, and require new skills. Many processors, contractors, and users (such as local governments), lack the experience necessary to work with recycled materials testing procedures and markets, and do not have the time to research successful recycled projects.

Drywall

More information is needed about drywall's use in agriculture. Two studies provide some positive feedback, but more studies are needed that target California agriculture. In one study, ground drywall was compared with agricultural gypsum and limestone on a corn field in upstate New York, with positive results. The study recommended further research by applying ground drywall to a variety of soil types, deforested lands, and roadside soils with high concentrations of sodium from de-icing salts. (De-icing salts are used in two Caltrans districts, but the soil is monitored and apparently does not need treatment.) In the second study, an analysis was made of the chemical suitability of new drywall for agricultural use in California's Central Valley, with positive results.

Unique Industry Costs

Inerts recycling is a new industry. A new recycler must modify or purchase equipment; obtain additional permits, such as local land use permits; and pay additional labor costs. Air pollution control equipment is required at mobile sites, which makes many smaller jobs cost-prohibitive. Recyclers have more wear and tear on equipment, and locate in higher rent areas. Recyclers must charge tipping fees to cover costs, and these fees, together with transportation costs, must compete with landfilling. The final product also must compete with the virgin product. In addition, new products or procedures must be tested before specifications can be developed. Loan programs do not cover this type of expense.

VII.  Strategies to Overcome Barriers

Specifications

• Establish an MOU with Caltrans to develop and promote specifications for recycled-content road products.
• Identify a Caltrans liaison to work with CIWMB staff.
• Review existing Caltrans procurement requirements, including purchase orders, and give recommendations.
• Review existing Caltrans specifications and standards for possible barriers, and make recommendations for revisions.
• Work with Caltrans to identify the recycled-content products that are most feasible for them to encourage, identify Caltrans projects for pilot studies, and develop engineering data and specifications.
• Investigate, with Caltrans, the possibility of incorporating aggregate-base SSPs into the next version of Caltrans' Standard Specifications, due possibly in 1998 or 1999.
• Encourage Caltrans to finish testing recycled asphalt specifications, e.g. hot recycling and cold, in-place (SSPs were expected by mid-1996), multisource stockpiles, microwave process, and hot, in-place. Get Caltrans' commitment for specific completion dates for these specifications.
• Encourage Caltrans to finish testing ground asphalt roofing shingles in AB and ASB this spring for possible inclusion in the SSPs.
• Investigate, with Caltrans, options for testing and developing specifications for asphalt roofing shingles in aggregate base and asphalt. Options might include seeking outside sources of funding for testing.
• Investigate, with Caltrans, the feasibility of allowing the use of leftover batches of liquid concrete in new concrete, with appropriate safeguards for lower quality batches.
• Work with local governments to promote local testing and specification development for recycled-content road products.

Negative Perception

Disseminate information as outlined in the next section.

Lack of Information

Hold regional workshops for inerts recyclers, city/county engineers, and others for education and problem solving.

Collect and disseminate the following information to appropriate State and local governments, businesses, and organizations:

• Summaries of technical reports, existing specifications, Caltrans' SSPs, guidelines, case studies (including money saved, life-cycle cost comparisons, Caltrans projects, local recycling policies, and local landfill bans, etc.); fact sheets, databases, sample contract language, etc.
• Instructions for accessing electronic versions of Caltrans SSPs from the World Wide Web.
• Examples of local policies. For example, local policies may require contractors to submit a waste management plan, or to source separate recyclables, in order to obtain building and demolition permits. To assist the contractor, helpful information can be attached to permits, such as a local processors list, and an economics worksheet (to determine economic viability of recycling on a project).
• The State Water Resources Control Board's consideration of old asphalt as an inert.

Write a joint fact sheet with Caltrans, CalTrans Product Approval Process, to distribute to local governments and manufacturers.

Estimate tonnages potentially diverted with Caltrans' use of specific road products.

Place inerts recycling fact sheets and databases on CIWMB home page on the World Wide Web.

Promote recycled inerts through professional organizations, by writing articles for their publications, and sending them fact sheets, case studies, etc. Example organizations are the American Public Works Association (national and chapter), the American Society of Civil Engineers (national and chapter), the League of California Cities, Local Government Commission, County Supervisors Association of California, and other organizations as appropriate.

Work with local governments to promote recycling of construction and demolition waste.

Continue to give customized assistance to businesses via the "California Recycling Business Assistance Team," or "R-Team," which is a Board program funded in part by a U.S. EPA grant.

Consider contracting (on a temporary basis) an expert from the construction industry to network and promote recycled inerts within industry.

Supply local recycling coordinators with lists of construction and demolition recyclers to distribute to local construction-related businesses, such as building materials distributors and concrete sawing companies.

Fund joint government/private studies on the use of ground drywall in compost, on agricultural soil, and on deforested land.

Unique Industry Costs

Establish an MOU with Caltrans to cosponsor legislation or set policies to encourage use of recycled-content road products.

Establish an MOU with Caltrans to study the economics of recycling road products.

Facilitate permitting of inerts recycling operations by:

a. Assigning concrete, asphalt, roofing shingles, and other inerts into the lowest tier or as an exemption in the solid waste facilities' tiered permitting system, to allow long term storage and processing.

b. Working with other permitting agencies such as the Air Resources Board and State Water Resources Control Board to develop consistent policies.

Investigate, with the Air Resources Board, the idea of pollution control credits, so that processing solid waste will offset restrictions on other areas.

Investigate backhauling possibilities for drywall recyclers. For example, drywall scraps can be hauled from urban generation sites in agricultural trucks that are otherwise returning empty to rural areas where agricultural gypsum markets are.

Distribute the Board's disaster plan (currently in draft), which discusses inerts recycling and the selection of storage sites before a disaster occurs.

VIII.  Summary

Major Barriers

The primary barriers to inerts recycling are lack of specifications, negative perception, lack of information, and unique industry costs.

Lack of Specifications

Caltrans is the most important agency for development of road construction specifications because Caltrans projects require large volumes of inerts, and because most local governments use Caltrans specifications. Caltrans' existing specifications for recycled road base are not included in their specification book. Caltrans' recycled asphalt specifications are long overdue, and have been repeatedly postponed due to their other priorities. Caltrans does not have specifications for ground asphalt roofing shingles in road base or asphalt.

Negative Perception

Many city and county engineers are leery of using recycled inerts because they assume its quality is inferior to virgin, and are reluctant to change to an unknown product due to liability concerns.

Lack of Information

When setting up new operations, potential recyclers often need guidance in permitting requirements, markets, and technology. Many city and county engineers are reluctant to try a new recycled product because they lack experience with recycled materials testing procedures. Many farmers are reluctant to use reclaimed drywall on their fields because they lack information about its quality.

Unique Industry Costs

Inerts recyclers have costs that are unique to the industry, such as modifying equipment, obtaining additional permits, additional labor costs, and higher land costs. 

Strategies

Recommended actions are summarized below.

Lack of Specifications

The Board should establish an MOU with Caltrans to develop and promote specifications for recycled-content road products. Assist Caltrans in testing and give encouragement and funding where necessary, particularly for the use of asphalt roofing shingles in asphalt pavement and aggregate base, and reclaimed asphalt pavement (RAP) in asphalt. Work with local governments to promote local testing and specification development for recycled-content road products.

Negative Perceptions/ Lack of Information

Collect and disseminate information on inerts recycling to industry, local governments, and the public via workshops, mailings, and Internet, and through professional organizations. Give customized assistance to individual businesses via R-Team. Consider hiring construction experts to promote recycled inerts within industry. Consider funding studies on the use of ground drywall in soil enhancement applications.

Unique Industry Costs

Direct CIWMB staff to enter into an MOU with Caltrans to investigate the economics of recycling road products, and investigate co-sponsoring legislation or setting policies, to encourage use of recycled-content road products. Assign inerts into the lowest solid waste facilities tier in the solid waste facilities' tiered permitting system to allow long term storage and processing; distribute the Board's disaster plan (when complete) which discusses the selection of storage sites; and help create consistent policies by coordinating with other State permitting agencies.

1996 Market Development Plan

Last updated: November 01, 2007