USE OF PHOSPHATE MINING WASTE IN SECONDARY ROAD CONSTRUCTION

A pilot study was undertaken to provide alternate methods of rebuilding county and other secondary roads using phosphogypsum, a phosphate mining waste that is abundant in fertilizer-producing countries, as an aggregate and stabilizer. Current construction practice for some of these roads consists of mixing and further compacting the generally granular soil subgrade with fine-grained soils that are transported to the site. These mixtures tend to be largely affected by changes in the moisture regime. Several phosphogypsum-sand mixtures have been studied, mainly under California Bearing Ratio tests, as well as unconfined compression tests, to determine their engineering properties under different curing conditions, as well as to find useful design parameters. Both dihydrate and hemihydrate phosphogypsum were used throughout this investigation. Most of these mixtures yielded significant strength and bearing gains; however, some of them also became unstable when soaked. A rapid-curing cutback asphalt, RC-70, was added to the mixtures to decrease their moisture susceptibility. It was found that a very small percentage of RC-70 is required for specimens to develop such water resistance. Several alternatives that would perform acceptably when used in the construction of secondary roads are presented in this paper.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1987/1106v1/1106v1-009.pdf
• Record URL:
  • https://scholar.google.com/scholar_lookup?title=USE+OF+PHOSPHATE+MINING+WASTE+IN+SECONDARY+ROAD+CONSTRUCTION&author=J.+Figueroa&author=L.+Zhou&author=W.+Chang&publication_year=1987
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309044545
• Supplemental Notes:
  • This paper appeared in Transportation Research Record N1106, Fourth International Conference on Low-Volume Roads, Volume 1. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Figueroa, J Ludwig
  • Zhou, Liang
  • Chang, Wen F
• Conference:
  • International Conference on Low Volume Roads, 4th, 1987, Ithaca, New York, USA
• Publication Date: 1987-8

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 59-64
• Monograph Title: FOURTH INTERNATIONAL CONFERENCE ON LOW-VOLUME ROADS. VOLUME 2
• Serial:
  • Transportation Research Record
  • Issue Number: 1106
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: California bearing ratio; Impacts; Mining; Properties of materials; Reconstruction; Secondary roads; Testing; Wastes; Water
• Uncontrolled Terms: Phosphogypsum
• Old TRIS Terms: Cbr testing; Mining waste; Unconfined compression tests; Water effects
• Subject Areas: Construction; Environment; Geotechnology; Highways; Materials; I33: Other Materials used in Pavement Layers; I52: Construction of Pavements and Surfacings;

Filing Info

• Accession Number: 00473098
• Record Type: Publication
• ISBN: 0309044545
• Files: TRIS, TRB
• Created Date: Sep 30 1987 12:00AM