UTILIZATION OF REEF SHELL IN FLEXIBLE PAVEMENT CONSTRUCTION IN THE GULF COAST AREA

AN ALL-SHELL BASE COURSE IS THE HIGHEST TYPE OF BASE COURSE THAT CAN BE OBTAINED WITH 100 PERCENT REEF SHELL AGGREGATE. NO ADMIXTURE IS REQUIRED TO SUPPLY THE FINE AGGREGATE FRACTION BECAUSE THIS IS DEVELOPED IN THE BREAKDOWN OCCURRING DURING COMPACTION WITH THE TAMPING TYPE ROLLER. THE BASE IS FREE OF SHRINKAGE CRACKS AND NOT SERIOUSLY AFFECTED BY HIGH WATER CONTENT BECAUSE OF VERY LOW PLASTICITY. UNIT WEIGHT IN EXCESS OF 100 PERCENT MODIFIED AASHO DENSITY AND IN-PLACE CBR IN EXCESS OF 80 PERCENT CAN BE READILY OBTAINED. SINCE AN ALL-SHELL BASE COURSE IS CAPABLE OF SUPPORTING VERY HEAVY WHEEL LOADS, IT IS RECOMMENDED FOR HIGHWAYS IN THE INTERSTATE SYSTEM. A HIGH- STRENGTH BASE COURSE CAN ALSO BE OBTAINED WITH A MIXTURE OF LOCAL SAND AND REEF SHELL WHERE THE SAND CONTENT DOES NOT EXCEED 20 TO 30 PERCENT. AVAILABLE INFORMATION INDICATES THAT THE SAND CONTENT SHOULD BE SET AT MAXIMUM OF 20 PERCENT FOR AIRFIELDS AND INTERSTATE HIGHWAYS TO INSURE AN IN-PLACE CBR OF 80 PERCENT. HOT-MIX ASPHALTIC CONCRETE WITH CRUSHED REEF SHELL AGGREGATE PROVIDES HIGH-TYPE AND DENSE FLEXIBLE PAVEMENT. MANY MIXES CAN BE PRODUCED FROM STOCKPILES OF DREDGED SHELL, SHARP RIVER SAND AND FINE SAND BECAUSE THE SHELLS ARE CRUSHED TO THE DESIRED MAXIMUM SIZE AFTER DRYING. FOR A GIVEN GRADATION, THE STABILITY, FLOW, AND UNIT WEIGHT ARE NOT SENSITIVE TO VARIATION IN ASPHALT CONTENT. THE ASPHALT CONTENT MUST BE SELECTED FOR THE DESIRED VOIDS PROPERTIES RATHER THAN AVERAGING VALUES UNDER THE MARSHALL METHOD. THE MAXIMUM PRACTICABLE SIZE OF CRUSHED REEF SHELL IN ASPHALT MIXES IS 3/4 IN. AS DETERMINED BY STANDARD SCREENING BECAUSE OF THE PARTICLE SHAPE. HOT MIX FOR COLD APPLICATION UTILIZING CRUSHED REEF SHELL AGGREGATE PROVIDES A HIGH-TYPE AND DENSE FLEXIBLE PAVEMENT VERY SIMILAR TO THE SHELL HOT MIX OF A COMPARABLE GRADATION. THE MATERIAL CAN BE STOCKPILED FOR MAINTENANCE PURPOSES OR USED IMMEDIATELY FOR PATCHING, RESURFACING OR NEW CONSTRUCTION.

• Supplemental Notes:
  • Vol 27, pp 323-355, 6 FIG, 3 TAB
• Authors:
  • MEREDITH, E C
• Conference:
  • Assoc Asphalt Paving Technol Proc
• Publication Date: 1958

Subject/Index Terms

• TRT Terms: Aggregate gradation; Aggregates; Asphalt concrete; Base course (Pavements); California bearing ratio; Cold mix paving mixtures; Compaction; Fine aggregates; Flexible pavements; Flow; Hot mix asphalt; In place density; Maintenance; Paving; Rollers; Sand; Screenings; Stability (Mechanics); Stockpiling; Tamping; Void ratios; Weight
• Identifier Terms: Interstate Highway System
• Uncontrolled Terms: Particle size distribution
• Geographic Terms: Gulf Coast (United States); Gulf of Mexico
• Old TRIS Terms: Gradation; Shell aggregates; Tamping rollers; Unit weight; Void
• Subject Areas: Construction; Geotechnology; Highways; Maintenance and Preservation;

Filing Info

• Accession Number: 00214845
• Record Type: Publication
• Files: TRIS
• Created Date: May 21 1994 12:00AM