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GUIDELINES FOR RECERTIFICATION OF STOCKPILES

 

It may become necessary to re-certify a stockpile for gradation that was previously certified. Below are guidelines for deciding when recertification is needed and when it may not be necessary. 

 

When it may be necessary:

 

• Stockpiles that appear to be contaminated.   

 

• Stockpiles from ledges that have a history of generating minus No. 200 fines over time.

 

• HMA coarse aggregate produced from low quality ledges or ledges that incorporate a blend of high and low quality beds may need to be recertified if held over the winter.

 

• Class A made from ledges with abrasion over 40 and C-freeze over 5 may need to be re-sampled if held over the winter.

 

 

When it may not be necessary:

 

• Stockpiles of porous backfill, concrete sand, or washed products with low alumina/A-freeze specifications probably will have no “breakdown” over a winter due to freeze-thaw damage.

 

• In general, stockpiles with low alumina/A-freeze washed products produced on the coarse side of the gradation specification where the minus No. 200 mesh sieve was low the previous year.

 

• Stockpile recertification is not necessary for Class A produced with a coarse gradation from most ledges.