POTENTIAL ERRORS IN THE FAA TEST

摘要

One of the problems in dealing with manufactured sands is the lack of a set of tests that fully characterize the three main properties of the individual particles. The properties that we should be trying to characterize are: (1.) particle shape, (2.) particle size, (3.) particle surface texture. Not only do we need to know these individual properties of the aggregates, we need to know how these properties influence the concrete in both its hardened and plastic states. It is also desirable to understand how the properties of each of the aggregate sizes, or material types, impacts on the entire aggregate blend. Particle interactions are an issue that is not adequately addressed by the concrete standards of today. Logic should dictate that, for specifications of particle size distribution, we should be looking at the entire gradation, i.e., the sand and aggregate fractions together, so that we can with more certainty have a common-sense overall gradation in the concrete mix. The paper addresses results of a test series which evaluated the effectiveness of ASTM C 1252 for assessing fine aggregate angularity (FAA).