The “Wet Ball Mill” test, as specified by the Texas Department of Transportation (TxDOT), is a standardized procedure used to evaluate the degradation of aggregates under wet conditions, simulating the effects of mechanical abrasion and water. This test is part of the Tex-116-E or similar TxDOT test methods.
TxDOT Wet Ball Mill Test Overview
1. Purpose:
– Measures the resistance of aggregates (e.g., base materials, crushed stone) to breakdown when subjected to wet grinding in a ball mill.
– Helps assess durability for use in road construction.
2. Apparatus:
– Ball Mill: A rotating drum with steel balls (typically 12–18 balls).
– Sieves (No. 10 and No. 200).
– Water supply for wet grinding.
3. Procedure:
– A sample of aggregate is placed in the mill with water and steel balls.
– The mill rotates for a specified number of revolutions (e.g., 1,000–5,000).
– The material is then washed and sieved to determine the percentage passing a No. 10 or No. 200 sieve, indicating degradation.
4. Calculations:
– The Wet Ball Mill (WBM) value is calculated as:
\[
\text{WBM Value (\%)} = \frac{\text{Weight passing No. 10 sieve}}{\text{Original weight}} \times 100
\]
– Lower values indicate more durable aggregates.
5. TxDOT Specifications:
– Maximum allowable WBM values vary by material type (e.g., base courses may require ≤ 40–50%).
– Refer to Tex-116-E or
her relevant TxDOT standards for exact limits.
Key Considerations
– Used alongside other tests like Los Angeles Abrasion (LAA) and Micro-Deval.
– Critical for materials in high-moisture or high-traffic areas.
For exact procedures and acceptance criteria, consult the latest TxDOT Test Procedures Manual or contact TxDOT’s Materials & Tests Division.
Would you like help interpreting results or finding related tests?
Leave a Reply