Kiessande für sekundäre Strassen | Aggregates for Low Volume Roads

Gravel is the most important material for road construction. In most countries the quality of gravel for sub-base and base is standardised. The Association of Swiss Road and Traffic Engineers recently revised the Swiss SN standard 670 120d for subbase gravel. Quality requirements concerning the admissible content of fine particles and the limits of particle size distribution were intensified, for no obvious reason. Former studies and experiences proved that these stricter specifications are neither necessary, from a soil-mechanical point of view, nor economical. For low volume roads, such as forest and rural roads, it is therefore suggested to use the limits of particle size distribution for gravel II (except for crushed rock aggregates),but a clearly higher amount of fine particles can be accepted.