Work Item
ASTM WK81517
Revision of D7428-15 Standard Test Method for Resistance of Fine Aggregate to Degradation by Abrasion in the Micro-Deval Apparatus
Rationale
Section 11 requires the use of Standard Sutherland Micro-Deval Fine Aggregate; however, this aggregate can no longer be obtained. Laboratories that do not have access to Standard Sutherland Micro-Deval Fine Aggregate are now using MTO RM FA3 Reference Aggregate. The newer reference aggregate has a different mean and range, and the gradation requirements of Section 7.1 do not apply. The standard requires 95% of the reference aggregate test results to fall within the specified range. However, the laboratory is only running 10 samples, and this would simply entail that all 10 fall within the specified range. Plotting data on a trend chart for the in-house calibration aggregate is required, and reference is made to Figure 1. However, the standard doesn't specify what elements need to be on the chart (limit lines and mean?), except for the percent loss. The standard doesn't explain how to determine the range for the in-house calibration aggregate (2 standard deviations from the mean?). These and other requirements of Section 11 require elaboration and correction.
Work Item Status
Date Initiated: 04-12-2022
Technical Contact: Pete Holter
Item: 000
Ballot:
Status: