Aggregates from Natural and Recycled Sources Economic Assessments for Construction Applications—A Materials Flow Analysis By David R. Wilburn and Thomas G. Goonan U.S. GEOLOGICAL SURVEY CIRCULAR 1176 T OF EN TH TM E R I A N P T E E D R . I O S . R U M 9 A 8 4 R C H 3, 1 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Thomas J. Casadevall, Acting Director Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government This report is only available on-line. http://greenwood.cr.usgs.gov/pub/circulars/c1176/c1176.html Published in the Central Region, Denver, Colorado Manuscript approved for publication June 1, 1998 Edited by Lorna Carter Graphics by David R. Wilburn and Thomas G. Goonan On-line composition by Joan G. Nadeau CONTENTS Abstract........................................................................................................................... 1 Executive Summary........................................................................................................ 1 Introduction ....................................................................................................................3 Structure of the Aggregates Industry.............................................................................. 3 Aggregates Processing Technology................................................................................ 6 Technical Factors Affecting Aggregates Recycling............................................... 8 Transportation Factors............................................................................................ 11 Locating an Aggregates Recycling Facility............................................................ 12 Costs of Producing Recycled Aggregates ...................................................................... 13 Methodology........................................................................................................... 13 Costs ....................................................................................................................... 13 Sensitivity Analysis ................................................................................................ 19 Public Policy...................................................................................................................24 Conclusions .................................................................................................................... 26 Selected References........................................................................................................ 27 Appendix 1. State Concrete Recycling Activity............................................................. 29 Appendix 2. Aggregates Production Technology........................................................... 31 FIGURES 1. Construction aggregates flow system .................................................................................................................... 4 2. Pie charts showing consumption of aggregates by source and market sector ....................................................... 5 3. Generalized flow diagram for an aggregates recycling operation ......................................................................... 9 4. Diagram illustrating locating a concrete recycling facility ................................................................................... 12 5–7. Histograms showing: 5. Estimated 1996 costs for a 110,000 t/yr recycled aggregates operation........................................................ 16 6. Estimated 1996 costs for a 253,000 t/yr recycled aggregates operation........................................................ 17 7. Estimated 1996 costs for a 312,000 t/yr recycled aggregates operation........................................................ 18 8. Diagram showing estimated costs and revenues of recycled aggregates............................................................... 20 9–11. Graphs showing: 9. Profitability of a 110,000 t/yr recycled aggregates operation........................................................................ 21 10. Profitability of a 253,000 t/yr recycled aggregates operation........................................................................ 22 11. Profitability of a 312,000 t/yr recycled aggregates operation........................................................................ 23 12. Photograph showing typical natural aggregates operation .................................................................................... 31 13. Photograph showing typical recycled aggregates operation.................................................................................. 35 TABLES 1. Significant technological aspects of natural and recycled aggregates.................................................................. 7 2. Material requirements for a typical highway project............................................................................................ 11 3. Assumptions used in this evaluation..................................................................................................................... 14 4. Estimated 1996 costs for recycled aggregate operations...................................................................................... 15 5. Crusher combinations commonly used in concrete and asphalt recycling........................................................... 36 III AGGREGATES FROM NATURAL AND RECYCLED SOURCES Economic Assessments for Construction Applications—A Materials Flow Study By David R. Wilburn and Thomas G. Goonan ABSTRACT Costs for three representative operations of different sizes were modeled in this study. Under study conditions, all Increased amounts of recycled materials are being used were found to be profitable and highly dependent upon local to supplement natural aggregates (derived from crushed tipping fees and market prices, which can vary significantly stone, sand and gravel) in road construction. An understand- by location. Smaller operations were found to have different ing of the economics and factors affecting the level of aggre- operational dynamics, often requiring creative marketing or gates recycling is useful in estimating the potential for incentives to maintain profitability. recycling and in assessing the total supply picture of aggre- Nationally, consumption of recycled aggregates from gates. This investigation includes a descriptive analysis of the crushed concrete increased 170 percent between 1994 and supply sources, technology, costs, incentives, deterrents, and 1996, but constituted less than 0.4 percent of total aggregates market relationships associated with the production of aggre- consumed in 1995. The supply of construction debris is gates. Results derived from cash flow analyses indicate that regional, and is determined by local infrastructure decay and under certain conditions aggregates derived from construc- replacement rates. Aggregate recycling rates are greatest in tion and demolition debris or reclaimed asphalt pavement can urban areas where replacement of infrastructure is occurring, economically meet the needs of certain markets, but this natural aggregate resources are limited, disposal costs are material can only supplement the use of natural aggregates in high, or strict environmental regulations prevent disposal. construction applications because the available supply is Consumption is expected to grow as construction contractors much less than total demand for aggregates. Producers of nat- recycle as a means of saving on transportation, disposal, and ural aggregates benefit from their ability to sell a wide, higher new material costs and natural aggregate producers include valued range of aggregate products and will continue to dom- recycled material as part of their product mix in order to pro- long the life of their reserves and improve product revenues. inate high-end product applications such as portland cement In some locations, the amount of material available for recy- concrete and top-course asphalt. cling is insufficient to meet present industry demand. The use Although recycled aggregates can be used in a variety of of recycled aggregates should be evaluated locally based road construction applications, product variability and upon relative cost, quality, and market factors. Policy makers strength characteristics usually limit their use to road base, often must weigh the potential benefits of recycling with backfill, and asphalt pavement. Quality of the products con- competing land use, development issues, and economic and taining recycled material is often source dependent, and societal pressures. indiscriminant blending may lead to inferior performance. Careful feed monitoring, testing, and marketing can broaden the use of recycled aggregates into other applications. EXECUTIVE SUMMARY Aggregates recycling is most likely to be successful where transportation dynamics, disposal and tipping fee Much of our Nation’s infrastructure (roads, buildings, structures, resource supply/product markets, and municipal and bridges) built during the middle twentieth century is in support are favorable. Recycling operations often must over- need of repair or replacement. A large volume of cement- and come risks associated with feed and product availability, pric- asphalt-concrete aggregates will be required to rebuild this ing, and quality. infrastructure and support new construction. Use of 1 2 AGGREGATES FROM NATURAL AND RECYCLED