PHASE II REPORT - Caltrans

The recommended mixing procedure for the AMT is the following:
1. Choose mix components from existing information or TB-113 and determine the
percentage of each component based on the weight of dry aggregate.
2. Weigh 300g of dry aggregate into the small stainless steel bowl.
3. Add cement or other dry additive and mix thoroughly.
4. Add water and mix thoroughly.
5. Add liquid additive and mix thoroughly.
6. Add emulsion and mix quickly for 5 to10 seconds.
7. Immediately after mixing the emulsion, place the bowl in the AMT machine, clamp, and
lower stirrer to within 0.40 - 0.78 inches (1-2 mm) from the bottom of the bowl and
assure that the stirrer is centered.
8. Turn on AMT unit and mix 5 seconds.
9. Set test speed to 50 rpm.
10. Measure trace for 10 minutes.
11. Record steady state torque as the Mix Index, record time where steady increase of
torque begins as the Mix Time.
12. Record time where torque reaches (12 N-cm) as the Spread Time.
13. Record time when mix is broken by observation.
C) Effect of System Type:
To evaluate the effectiveness of the recommended AMT procedure, systems with E1 and E2
emulsion were measured. Systems with three different consistencies, Soupy (S) or Low
Viscosity (LV), Stiff (St), and Moderate Viscosity (MV) were evaluated and observations noted.
Mix M4 was chosen as the system with Soupy consistency. In Figure 4.13, the mixing Torque
was observed to be (6 to 7 N-cm). It was also noted that the mix M4 did not break until after the
AMT was stopped.
For the stiff system, Mix M1, the mixing torque was recorded to be (9 to10 N-cm) and the mix
time about 3.5 minutes. At this point in time, the torque was noticeably beginning to increase.
The trace is shown in Figure 4.14.
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