FIELD MANUAL For HOT MIX ASPHALT (HMA) - Mississippi ...

The calculations for test 2 shall be the average dry back correction from tests 1 and
2. After the first two tests, the dry back correction shall be the average of all
previous dry back tests. For subsequent days of production, use the dry back
correction available at the start of the day for all tests conducted that day even if a
new dryback correction is determined during the day. An example of the dry back
correction calculations for a project is given on the attached dry back summary sheet
(Figure 1). The correction shall be used as given in the following schedule:
Day 1 Test 1 - Use dry back from test 1.
Test 2 - Use average dry back from tests 1 and 2.
Test 3 - Use average dry back from tests 1 and 2.
Test 4 - Use average dry back from tests 1 and 2.
Day 2 Test 5 - Use average dry back from tests 1 and 2.
Test 6 - Use average dry back from tests 1 and 2.
Test 7 - Use average dry back from tests 1 and 2.
Day 3 Test 8 - Use average dry back from tests 1 and 2.
Test 9 - Use average dry back from tests 1 and 2.
Test 10 - Use average dry back from tests 1 and 2.*
Test 11 - Use average dry back from tests 1 and 2.*
Day 4 Test 12 - Use average dry back from tests 1, 2, and 10.
Test 13 - Use average dry back from tests 1, 2, and 10.
FIGURE 1
(Example Maximum Specific Gravity Dry Back Correction Calculations)
Maximum Specific Gravity Dry Back Correction Summary Sheet
(Y)
G mm (X-Y) Cum. No.
w/Dry Difference Difference of
Back
Tests
Date Test (X)
G mm
Average
Difference
Corrected
G mm
Day 1 1 2.508 2.505 0.003 0.003 1 0.003 2.505
2 2.508 2.503 0.005 0.008 2 0.004 2.504
3 2.518 - - - - 0.004 2.514
4 2.514 - - - - 0.004 2.510
Day 2 5 2.509 - - - - 0.004 2.505
6 2.503 - - - - 0.004 2.499
7 2.502 - - - - 0.004 2.498
Day 3 8 2.515 - - - - 0.004 2.511
9 2.505 - - - - 0.004 2.501
10 2.507 2.500 0.007 - 2* 0.004 2.503
11 2.504 - - - - 0.004 2.500
Day 4 12 2.501 - - 0.015 3 0.005 2.496
13 2.498 - - - - 0.005 2.493
Rev. February 5, 2007 32