REVIEW OF AGGREGATE BLENDING TECHNIQUES

A number of aggregate blending methods have been proposed and used since the work of Fuller and Thompson on propertioning concrete. In this paper, a review of these methods is made, from the simplest trial-and-error method for two aggregates to the most sophisticated mathematical method based on theories of least squares and use of electronic computers. Six major methods are examined: trial and error, triangular chart, rectangular-chart or straight-line method and variations, Sargent's (triangular-prism projection) method, Rothfuchs' (balanced area) method and modification by the Japanese Highway Institution, and mathematical method and its variations. A general discussion of grading requiremnts and the general principles and procedures of aggregate blending problems are presented. For each method reviewed, the specific theories and steps are described, the applications and limitations are suggested, and one or more examples are given to illustrate the method. /Author/