Correlation of results between the test sand´s equivalent and methylene blue spot test in granular materials

Abstract

The nature of the materials coming from different material sources (quarries) presents differences in the quantity and composition of the fines (it passes sieve No.200). The technical specifications make reference to the sand equivalent test like a qualitative indicator of this characteristic. However it is indispensable to define the harmfulness of these fines. When a material doesn’t fulfill this requirement it is necessary to improve its idealization by means of tests or techniques of characterization. The methylene blue spot test is a current, quick and useful technique of quality control of the fine fraction as an indicator of presence of clays in a material sample. The present investigation defines the correlation among the following tests: sand equivalent, methylene blue (spot test) and Atterberg limits. These tests showed exponential, potential and lineal relations and the clay fraction detrimental incidence in a granular material. It was feasible to observe this incidence through the methylene blue spot test