Procedure for Classification of Coarse Aggregates Based on Properties Affecting Performance (1244-9)

Course aggregate is the major constituent of both Portland cement concrete and asphalt concrete and is therefore widely used for construction purposes. A classification system for coarse aggregates would provide a systematic means for the identification of aggregates which could be used in the selection of aggregates for different construction activities.|The objectives of this research were as follows: (1) to characterize the aggregates based on their properties, (2) to develop a framework for an Aggregate Classification System (ACS), (3) to provide the basis for the implementation of ACS, and (4) to recommend test procedures and equipment needed to carry out tests on aggregates as required by the ACS.|The classification system is developed in two stages: (1) comprehensive aggregate classification system incorporating all significant aggregate properties affecting pavement performance, and (2) simplified version of the comprehensive aggregate classification system. The ACS is recommended for implementation at three levels: (1) identification of aggregates, (2) simplified aggregate evaluation, and (3) detailed aggregate evaluation to supplement (1) and (2) as needed.|This report also discusses the basic tests recommended for aggregate evaluation and lists the required equipment for these tests. Aggregate properties and their respective performance indicators are tabulated. Various areas of further research are identified and recommendations are made for the implementation of the proposed classification system.