Quantity of Fines Produced During Crushing, Handling, and Placement of Roadway Aggregates
A three part test procedure was developed to determine the quantity of fines produced during crushing, handling, and placement of aggregates used as base course in roadway construction. The first test simulates crushing at the aggregate source. It involves processing an aggregate sample of specified gradation through a small laboratory jaw crusher. The second test simulates handling by agitating an aggregate sample of specified gradation at 10% moisture content for 20 min. The modified American Association of State Highway and Transportation Officials (AASHTO) compaction test is used to simulate placement. Following the conduct of each test in the procedure, the fines are measured by washing the aggregate over a 75-µm (No. 200) sieve. At the conclusion of the three part test procedure the fines produced during crushing, handling, and placement are determined by summing the fines determined from each test in the series. The maximum fines produced with the procedure developed were correlated to with the Washington Degradation Test results for samples obtained from six aggregate sources in Alaska. In all cases, a poor correlation was found. Owing to the lack of a large body of well-documented field data, the three part test procedure can only be used at this time to determine the maximum quantity of fines that is likely to be produced for a given crushing, handling, and placement history.