A method for estimating the condition of gravel roads forms an important part of a management systems which is intended to lead to effective maintenance activities. The Sweish National Road Administration makes use of a method abbreviated VVMB 106 for rating gravel roads. The method considers roughness, loose gravel and dust. Roughness is rated as a single variable, including potholes, crossfall, corrugations and rutting. On the other hand, loose gravel and dust are rated separately and then combined as a single variable termed "binding ability". Representative 100 m long sections of the gravel road network are randomly selected for the actual meaurement of distresses. The condition of each 100 m. section is rated as class 1 (good), class 2 (acceptable), or class 3 (poor). The condition is considered satisfactory if the section belongs to class 1 or class 2 regarding roughness and binding ability; otherwise, it is judged unsatisfactory. The primary purpose of this thesis is to analyse VVMB 106 in order to determine its weakness and thereby develop a new and improved method. The thesis is based on a four-year research project and consists of five papers and appendixes. (Author/publisher)
Samenvatting