AR-ACFC: Mineral Admixture 1% Lime or Cement is mandatory
AR-ACFC: Flakiness Maximum Flakiness = 25 To insure good particle shape, and minimize particle breakage.
AR-ACFC: Sand Equivalent Minimum 55 To insure that there are not excessive amounts of clay in the aggregate Done on washed aggregate
AR-ACFC: Crushed Faces Minimum 95% Single Crushed Faces To insure good particle interlock and good frictional characteristics
AR-ACFC: Abrasion Maximum at 100 rev. 9 at 500 rev. 40 To insure that the aggregate will hold up to the wear and tear of traffic
AR-ACFC: Percent Carbonates Maximum 30% To minimize the amount of limestone which has a tendency to polish under traffic.
AR-ACFC: Mix Design Steps Prepare Aggregate Determine aggregate specific gravities Determine maximum theoretical specific gravity Check draindown Determine mix density
AR-ACFC: Design Determine aggregate specific gravities for fine and coarse mineral aggregate Calculate combined specific gravities (oven dry, saturated surface dry, apparent)
AR-ACFC: Design Determine the maximum theoretical specific gravity (Rice test) Done at 3.5 to 4.0% binder content Determine the amount of asphalt absorption.
AR-ACFC: Design Calculate Binder content: ((.38)(W) + 8.6)(2.620/C)= Binder content W=% water absorption C=combined oven dry specific gravity
AR-ACFC: Design Check Draindown using the Schellenberg test This test is performed in the laboratory in order to determine whether or not an unacceptable amount of binder drains down from the mix.
AR-ACFC: Design 1. Place Mix in a beaker 2. Place beaker in oven for 1 hour 3. Empty beaker 4. Determine % mass loss
AR-ACFC: Design Based on the results of the draindown test, adjust binder content if necessary
AR-ACFC: Design Determine mix density –Compact in Forney (4” diameter, 200 psi) –Determine density by volumetrics Information used for determining spread, may also calculate voids for information only
AR-ACFC: Typical Design Typically 2 stockpiles: 95% intermediates, 5% fines Typical binder content % (general range %) Over PCC add 1% to design binder content
ARAC Mix Design Considerations
ARAC: Purpose Highly flexible lift High quality structural lift Typically nominal 2 inch lift