Shape and Surface of Mineral Grains Automatically Determined for Mortar and Concrete Purposes Through Image Analysis

摘要

For a long time it has been attempted to obtain sufficient information about the shape and surface qualities of mineral and rock grains, i.a. of the material of concrete aggregates. There is today an automatic method, using computer technique and image analyses. With the 'PICAP' equipment from Linkoping University, the grain projections of length, width, surface perimeter and edge eveness are quickly determined, and many other functions derived from these. Controls have shown good reliability of the measured values. The measurement have been made on samples of natural sand as well as crushed materials of the fractions of the concrete sieve-series. Column diagrams have been made for median and quartile values of these fractions for comparison of samples. As may be expected, the natural glacifluvial sand in the fractions coarser than 0.125 mm has as a rule proved to have a higher axial equality and to have a more even surface than the crushed products. The difference between the latter is often small but details, of interest for the interpretation, have been noted. The present measuring system may, in certain circumstances, be recommended for testing of concrete aggregates and filler but also for testing in many other technologies.