CPU 5 Breakout Troubleshooting on the Grade Gary L. Mitchell, - - PowerPoint PPT Presentation

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Gary L. Mitchell, P.E.

Vice President—Airports & Pavement Technology American Concrete Pavement Association

CPU 5 Breakout— Troubleshooting

• n the Grade

Introduction Surface Defect Contained in aggregates Loader operations Don’t disperse in the mixer Shows up after paving

Prevention Stockpile Location Flat Facilitate unloading & stockpiling Pad or sacrificial layer Loader Operator

Determining Severity ASTM D 5340 PCI Standards 3 pop outs per square yard Size – can it be cored? Deleterious Material Requirements ASTM C 33 – 3% fine ag, up to 5% coarse ag Airfield project will not tolerate C 33 threshold Remove & Replace only if extensive or large clay balls

Repair Procedures Filling

Sandblasting Pressure washing Compressed air

Coring

Slightly larger than clay ball Partial depth core Epoxy fill

Summary

Prevention

Manage owner’s perception Assess extent of the problem Establish repair procedure