Hydrofobisten koekohteiden seurannat vuoteen 2015

Six test structures have done on roads from suffering spring thaw weakening with treatment agents providing hydrophobic properties to the treated materials in years 2005, 2008 and 2009. Test roads done in 2005 and 2009 are presented only shortly in this report, because a more accurate description has been presented in the earlier publications. The construction of the test structure done in 2008 has been presented more detailed in this report. Three of the hydrophobic test roads have been paved, two have been leaved without pavement and one have had paved and unpaved section. The total length of the test roads was about 2 km.
The follow-up of the hydrophobic test roads had mainly been based on visual investigations along with FWD- and road profiling measurements. Additionally, ground radar measurements and laboratory tests had been done according to the requirements of the case. The follow-up of the hydrophobic test roads has been continuation to the research work carried on the use of new treatment agents to improve properties of the moisture susceptible road materials at Tampere University of Technology’s Unit of Earth and Foundation Structures.
The worst problem on the test roads has been very weak subgrade soil or lower parts of the road structure during spring thaw weakening. Treatment of 0,15 - 0,20 meter layer with treatment agents providing hydrophobic properties has not prevented remarkable damaging in these test roads and two of the test roads has been rehabilitated during the follow-up time.
Maintenance and repair works have complicated significantly the estimation of the success of the unpaved test roads. It seems that use of treatment agents providing hydrophobic properties has eliminated spring thaw weakening of the wearing course. Likely, the first spring maintenance on one of the test roads has broken the uniform surface of the treated layer and afterwards dusting and rutting problems had been observed on that road. Ploughing of the road could also had been the trigger for the same problems. Essential issue for the unpaved roads treated with hydrophobic treatment agents is the suitability of the existing maintenance methods or developing of appropriate new maintenance methods if needed. According to the follow-ups, unpaved test roads are not recommended to be constructed before more accurate effects of the normal maintenance works to the treated layers are verified or it can be ensured that only beforehand agreed maintenance works will done.
On paved roads the treatment agents providing hydrophobic properties have performed reasonably or well. Conditions for economical use of hydrophobic treatment agents in these test roads will turn out based on the progress of damages in Maalahti’s and Virrat’s test roads. Hence follow-up of at least them should have continued.