A method of measuring the surface texture of aggregate

Summary A method has been developed for measuring quantitatively the surface texture of particles of concrete aggregate. Various possibilities were considered; the method adopted involves embedding a particle of aggregate in a synthetic resin and obtaining thin sections of the aggregate surrounded by the resin. The interface between stone and resin is magnified 125 times on a projection microscope and traced. The length of the profile obtained is measured by means of a map-measuring wheel and compared with the length of an unevenness line drawn as a series of chords. The difference between the two lengths is taken as a measure of the roughness. The reproducibility of the results is good but the variation between different parts of a stone is large. Thus it is necessary to obtain a considerable number of results in order to give a reliable average. This is largely because of the smallness of the sample length: one tenth of an inch. The method has been used to compare the roughness of a series of twelve dif...