Material: Recycled
Glass
Issue: The use of recycled glass as an alternative construction aggregate
has been growing over the last decade. Recycled glass cannot be collected, processed, and delivered
to a construction site and compete with the cost of aggregate on an
absolute basis. However, if
the right kind of economic incentives are in place, construction aggregate
can be a “relief valve” for excess collected material.
Although there are 5000 years of glass technology, before 1990
no comprehensive studies had ever been undertaken to determine the performance
of glass compared with natural aggregates.
In the last five years, however, there have
been a number of studies of the performance of glass as a construction
aggregate. The results of these
studies are a logical starting point for any group interested in developing
local construction uses for recycled glass.
Best
Practice: This
is a list of studies that are known to be available for purchase or
free.
Clean Washington
Center Glass Feedstock
Evaluation: This study, conducted in 1993 by Dames & Moore Consulting and funded
by the states of Minnesota, New York, California, Oregon, Washington,
and the Southwest Public Recycling Association, was the first public
overall evaluation of glass as a construction aggregate. The study resulted in a comprehensive five-volume report:
·
Using Glass as a Construction
Aggregate - Eight page summary brochure of test results with application recommendations.
An excellent introductory piece for contractors.
Report #GL-93-1.
·
Testing Program Design - testing standards, protocols,
and an overview of the characteristics to be tested. Report #GL-93-2.
·
Environmental Suitability Evaluation
- Four environmental issues: leachate testing, worker safety, analysis
of airborne dust, and contamination levels.
Report #GL-93-3.
·
Equipment Evaluation - A listing and discussion
of important characteristics of glass processing systems producing 3/4”
minus, an economic model and field evaluations of six systems. Report #GL-93-4.
·
Engineering Suitability Evaluation
- Results of physical testing. Data
in tabular and chart format. Report
#GL-93-5.
·
Evaluation of Cullet as a Construction
Aggregate - Summary of test results with model specifications and application recommendations.
Report #GL-93-6. Update: The
above CWC reports are no longer available.
They were originally produced in only hardcopy format, and have
not been converted to electronic media.
Instead, they have been incorporated into the CWC report, A Tool Kit for the Use of
Post-Consumer Glass as a Construction Aggregate, report number
GL97-5rpt, available from the CWC
web site. Additionally,
the Clean Washington Center has the following two fact sheets available:
·
Washington Department of Transportation Specifications
for Glass Aggregate - Text and discussion of WSDOT specifications for
100% glass aggregate and blended glass aggregate. Fact sheet #GL-95-3.
·
Construction Inspector’s Guide to Recycled
Glass Aggregate - Compares characteristics of glass to those of natural
aggregates in order to facilitate field inspection. Fact sheet #GL-95-2.
·
Clean Washington Center reports and fact sheets are
available its website at http://www.cwc.org/
Florida Institute
of Technology Developing Specifications
for Waste Glass and Waste-to-Energy Bottom Ash as Highway Fill Materials
- Volume 2 of 2 (Waste Glass), June 1995 - More longitudinal tests and a more analytical
approach than the Clean Washington Center report. Covers similar physical properties, with more
emphasis on organics leaching issues.
Available for order at 407-768-8000 ext. 7555.
Schmucker, Bruce
O., and Buffalini, Rick J., Pulverized
Glass and Landfill Liner Systems, A paper presented at the WasteTech
‘95 Conference. - Summarized in the April 1995, issue of Waste Age
magazine, a copy of this full paper was not available at this writing. However, from the Waste Age article,
it appears to contain excellent physical performance information.
University of
Missouri - Rolla Glasphalt Paving
Handbook - Written by Delbert Day and Robert Schaffer, this is the most complete
treatment of using recycled glass in asphalt, including historical and
longitudinal information. Prepared
for the Missouri Enterprise Business Assistance Center, Rolla, MO 65401.
Implementation: These references can serve
as a starting point for any group interested in developing specifications
for glass in aggregate applications.
Benefits:
There
have been a plethora of pilot projects using glass as an aggregate in
fill or in asphalt. Unfortunately,
a great amount of energy has been wasted in some projects by “reinventing
the wheel,” and then not capturing lessons learned for the benefit of
others. Recycling will gain the most by public reports
that add to and enhance existing knowledge.
Application
Sites: Engineering
offices, construction sites.
Contact: For more information about this Best Practice, contact
CWC, mailto:info@cwc.org.
Issue
Date / Update: November 1996
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