Geotechnical testing specialist Geolabs has said that demand for its Particle Size Indicator is growing and the solution is helping to improve on site classification of materials on site and in the laboratory.
The indicator, which was developed jointly with Sussex University professor in engineering geology David Norbury, has proved popular with the industry since its launch.
Graded samples of sands and silt are secured on to a stiff board to allow a direct visual comparison to those different sizes of materials and an indication of fine, medium and coarse sands.
Gravels can be assessed by trying to pass the particle through the square holes in the card. For example, a piece of medium gravel would pass through the 20mm medium gravel hole, but not the 6mm fine gravel hole. If a large particle that you can hold in your hand will not fit through the 63mm large gravel hole, then it is a cobble.
For the larger sizes, read-off the sieve sizes they would have to fit through the right-hand end of the card. For example, a large boulder would not pass through a 630mm square sieve, whereas a boulder would pass through that but get trapped by a 200mm hole.
According to Geolabs, the indicator has been accepted and used by all those working within the geotechnical fraternity, from drillers, engineers, environmentalists, technicians and academia.