Methods for Sampling and Determining Sieve Analysis of Aggregates Larger Than One and One-Half Inch Sieve.

Sampling of concrete aggregates larger than the 1-12-in. sieve poses special problems due to difficulties encountered in handling and shoveling crushed stone and gravel of large maximum size and the large amount of material required per sample. The object of this investigation was to compare different methods which might be used and determine what recommendations could be made for sampling and testing such samples for sieve analysis. In order to judge the effectiveness of the sampling, sieve analyses of the sampled materials were compared with the analysis of the lot ot material from which the samples were taken. Methods of sampling tested were grab sampling with a clamshell from the stockpile, trench sampling from trucks loaded with the aggregate, belt sampling while aggregate was being loaded into a storage bin, and grab sampling of materials being discharged from bin storage.