PHASE II REPORT - Caltrans

Automated Torque (kg-cm)
30
25
20
15
10
5
0
Automated
Automated Corrected
Equality Line
Linear (Automated)
y = 0.5711x
R 2 = 0.7073
All Data
0 5 10 15 20 25 30
Manual Torque (kg-cm)
Figure 4.21: Correction of Test Results from ACT.
As illustrated in Figure 4.21, the 1.75 correction factor can be used to bring the ACT results
within the range of values normally measured with the conventional wet cohesion test.
Another experiment run at the MACTEC laboratory in Phoenix consisted of calibration tests with
the two devices on 220 grit sand paper. A number of 10 measurements were taken with each
device. The average and standard deviation of the test results are given in Table 4.6
Table 4.6: Results of Calibration Tests on 220 Grit Sand Paper
Statistic
Conventional Wet Cohesion
Torque (kg-cm)
Automated Cohesion
Torque (kg-cm)
Average 19.90 11.22
Standard Deviation 0.99 1.14
57