00667641

Component

http://onlinepubs.trb.org...trr/1994/1437/1437-003.pdf

https://scholar.google.co...eals&publication_year=1994

Phosphogypsum is a by-product of the fertilizer industry, specifically the production of phosphoric acid from phosphate rock. It is produced in large quantities and generally disposed of by stockpiling in large stacks. An alternative to disposal is reuse as a construction material in some form. One such process to convert phosphogypsum to a usable product is the Davy McKee-Florida Institute of Phosphate Research thermal conversion sulfur recovery process, in which sulfur contained in the phosphogypsum is recovered and a slag aggregate by-product is produced. This study centers around the possible utilization of phosphogypsum-based slag aggregate as a substitute for coarse aggregate in portland cement concrete for highway construction. The physical properties of the slag aggregate, such as specific gravity, unit weight, gradation, and absorption, were determined for use in concrete mix design. The durability behavior of the slag aggregate was also explored, exclusive of cold weather performance, which would require further research if the aggregate were exported to northern climates. On the basis of the physical characteristics of the aggregate, a concrete mixture was developed and tested in both the fresh and hardened states. The specific properties evaluated were workability, unit weight, air content, and yield of the fresh concrete along with strength and deformation characteristics of the hardened concrete. The compressive strength, flexural strength, splitting tensile strength, modulus of elasticity, and Poisson's ratio results indicated that the slag aggregate performed well as a coarse aggregate in portland cement concrete and should perform satisfactorily in a highway pavement system.

This paper appears in Transportation Research Record No. 1437, Aggregates: Waste and Recycled Materials; New Rapid Evaluation Technology. 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

01401247

English

p. 19-26

1994-9

Transportation Research Record

0309055156

Figures (3) ; References (4) ; Tables (7)

Absorption; Aggregate gradation; Air content; Compressive strength; Concrete; Deformation; Durability; Flexural strength; Mix design; Modulus of elasticity; Performance evaluations; Physical properties; Poisson distributions; Poisson ratio; Portland cement concrete; Recycling; Slag; Specific gravity; Strength of materials; Tensile strength; Weight; Workability

Concrete strength; Phosphogypsum

Geotechnology; Highways; Materials; I32: Concrete; I35: Miscellaneous Materials

TRIS, TRB

Oct 11 1994 12:00AM

• ENGINEERING PROPERTIES OF SHREDDED TIRES IN LIGHTWEIGHT FILL APPLICATIONS
• EVALUATION OF FINE AGGREGATE ANGULARITY USING NATIONAL AGGREGATE ASSOCIATION FLOW TEST
• METHODOLOGY FOR IMPROVEMENT OF OXIDE RESIDUE MODELS FOR ESTIMATION OF AGGREGATE PERFORMANCE USING STOICHIOMETRIC ANALYSIS
• SILICEOUS CONTENT DETERMINATION OF SANDS USING AUTOMATIC IMAGE ANALYSIS
• TOWARD AUTOMATING SIZE-GRADATION ANALYSIS OF MINERAL AGGREGATE
• USING RECOVERED GLASS AS CONSTRUCTION AGGREGATE FEEDSTOCK
• WASTE FOUNDRY SAND IN ASPHALT CONCRETE