Influence of pavement moisture content on the load-bearing capacity of forest road

The aim of the study was to analyse the interaction between pavement moisture content and load-bearing capacity of an unpaved forest road. The selected experimental road sector was divided into three sections (A, B and C), which were flooded with three different amounts of water 10 mm (section A), 20 mm (section B) and 30 mm (section C), compared with the intense rainfall. Three series of tests were conducted at each section: prior to flooding (1st day of measurements), during the first 24 hours after flooding (2nd day) and during the next 24 hours after flooding (3rd day of measurements). Moisture content of structural layers of the road (surface course, base course and subbase course) were determined and the measurements using a light weight deflectometer (Evd, s/v) and a static plate (E1 , E2 , Io ) were conducted. Recorded averaged results clearly indicate a negative effect of an increase in pavement layers moisture content (e.g. resulting from heavy rainfall) on the forest road carrying capacity and on compaction parameters of its layers. On the third day of the measurements a decrease in the analysed modulus, on average between 16% (E2 ) and 25% (Evd) was observed, but a decrease in compaction by 16% (s/v) and 4% (Io).