PHASE II REPORT - Caltrans

Figure 4.22: Cohesion Abrasion Test Apparatus (CAT)
1. Effect of Test Specimen Base Support
Three base supports were evaluated: the first one was a 30 lb (13.6 kg) roofing felt, the second
was a stainless steel plate 8 inches (203 mm) thick, and the third was an aluminum plate 8
inches (203 mm). The effect that these support bases had on the test results was examined for
two mixes, M2 and M4. Results and recommendations are discussed together with the
assessment method for aggregate loss.
2. Effect of Assessment Method for Aggregate Loss
The assessment of material loss after abrasion was done as follows:
• Wet Loss Method – The initial weight of the specimen and support base were
recorded before abrasion. After the abrasion test, specimen and plate were patted
dry with paper towels. This resulting weight was the final weight and the difference
was recorded as the loss.
• Aggregate Loss Recovery Method - The initial weight of the specimen and support
base were recorded before abrasion. During and after abrasion, all loose aggregate
was recovered. The weight of the recovered aggregate was subtracted from the
initial weight of the specimen and support base to obtain the final weight.
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