Environmental Purchasing Bulletin #65:
Low-VOC Cold-Patch

• Introduction
• Cold-Patch Use in King County
  • Cold-Patch Producer joins Linkup Program
• For More Information
• Environmental Purchasing Program

Introduction

When potholes need a temporary repair, both "hot-mix" asphalt and "cold-patch" are used to repair the surface until the roadway can be re-surfaced. Most street repairs are made with "hot" asphalt, which must be delivered to the job site within a fixed period of time (or continually heated) and applied to the pothole before it hardens. But hot-mix asphalt is often too cumbersome and expensive for small street repairs, so many transportation engineers rely on "cutback" or "cold-patch" asphalt as a temporary solution. Typical cutback asphalts are made by "cutting" hot asphalt with petroleum solvents, which are Volatilizing Organic Compounds (VOCs), to prevent the asphalt from solidifying before it is applied. This process allows the product to be stored, transported or bagged for longer periods of time. Once applied to the roadway, the solvents can contaminate the environment, as they evaporate into the atmosphere and/or are carried away in stormwater runoff.

King County has begun using a new cold-patch product that has recycled content and does not contain any added VOCs. This low-VOC product uses compaction, not evaporation, to harden, so it greatly minimizes or eliminates the release of toxics into the atmosphere and stormwater runoff. In addition to these environmental benefits, installation consists simply of tamping-down the patch, which will support traffic as soon as it is installed. Also beneficial, this cold-patch can be left in place when a new surface is applied, whereas hot-mix patch must often be removed, due to incompatibility with the new surface material. This new cold-patch has been approved by the Washington State Department of Transportation.

The King County Roads Operations section has been evaluating the performance of a new cold-patch compound that will reduce the amount of VOCs released to the environment. This product is a dry, odorless, ready-to-use asphalt-based compound used to repair potholes, cracks, and other defects in paved surfaces. It contains 70% post-consumer asphalt

Since the beginning of the year, the County has ordered 400 bags or about 10 tons of product. According to the manufacturer, this is 200 --55 gallon drums worth of VOC's that have been prevented from being introduced into the air and water in King County so far this year. In 2001, Roads decided to include this cold-patch product on it's roads maintenance materials contract.

A Roads department leadworker described the product as working well. She said "An area on Orillia (Road) was patched by the crew and although a small part of it came up, it has outlasted the 'Hot-patch' next to it. I have filled many holes with this mix in a variety of situations and none (that I know of) have come up."

Cold-Patch Producer joins Linkup Program

The Y.K. Products company, which produces and distributes the U.S. cold-patch product, has become a client of the Link-Up program, of the Solid Waste Division's Waste Reduction and Recycling Section. This program provides marketing assistance to companies that are finding new ways to use recycled materials.

"U.S. Cold Patch contains no added petroleum-based volatiles found in typical cutback asphalt," says Erv Sandlin, LinkUp program manager, "so it will not expose road crews or the environment to the hazardous fumes and materials that most other patching materials contain. This also means there is less likelihood of contaminating stormwater runoff that could end up in our region’s salmon streams."

LinkUp was launched last year to encourage businesses and manufacturers to incorporate more recycled materials into their products. The program offers free information resources, technical expertise and promotional assistance to eligible businesses throughout the Puget Sound area

For More Information

Y.K. Products (produces US Cold Patch)

3407 109th St. SW #207

Everett, WA 98204

(425) 244-5000

King County LinkUp Program

Environmental Purchasing Program

The King County Environmental Purchasing Program assists County agencies in implementation of King County Executive Policy CON-7-1-2, which requires agencies to use recycled and other environmentally preferable products wherever practicable.

The program assembles information about these products and makes it available to specific agency users who can evaluate them and develop applications in County projects.

These environmental purchasing bulletins contain information about the results of product evaluations and other accomplishments of County agencies. We hope this information will help you find ways to use recycled materials in the work of your agency and that you will contact us if we can help you with further information or if you have suggestions.

Updated: July 31, 2001

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