Once the design life of a haul road expires, or traffic volume and/or truck types change, a haul road rehabilitation or upgrade is indicated, to ensure the road continues to perform it’s design function – safe, vehicle friendly and economic.
Re-design or rehabilitation will depend to a large extent on the existing subgrade, design layerworks and wearing course and the extent to which these meet the newly defined road-users needs, in terms of a category I, II or II road design.
For further details, see the book:
Mining Haul Roads: Theory and Practice
Roger Thompson, Rodrigo Peroni, Alex T. Visser
Published December 11, 2018
Reference – 294 Pages
Further technical background is available here.