Procedures for Evaluating Aggregate Gradation Specifications

Novak, Edwin C.; ,

Procedures for Evaluating Aggregate Gradation Specifications

by Edwin C. Novak, Jr., Michigan Dept of Transportation, Materials and Technology Div, Lansing, United States,

Document Type: Proceeding Paper

Part of: Materials: Performance and Prevention of Deficiencies and Failures

Abstract:

The construction and rehabilitation of transportation facilities annually consumes huge quantities of aggregates. And, the variability in supply and demand for these materials as well as environmental factors have all contributed to the existence of a wide variety of gradation specifications for materials having the same intended use. Agencies faced with a widening gap between revenues and costs are in need of finding ways to narrow the gap. One way is to modify gradation specifications to make use of lower cost aggregates and granular materials. However, most highway agencies have lost, via retirement, the experienced materials personnel needed to evaluate the effects of such modifications. For these reasons, it is essential that highway agencies have available simple reliable means to evaluate the performance characteristics and engineering properties of materials produced in accordance with any given gradation specification and to develop new grading requirements for specific highway work items. The paper presents simple methodology for evaluating and developing grading requirements. Because the performance of any given gradation is also dependent on geometric properties of the constituent particles, simplified means to deal with this property and its interaction with gradation are presented. Methodology for blending aggregates and sands to produce desired products is illustrated.

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