Effect of spring and overload on the rutting of a low-volume road, HVS-Nordic-research

The aim of the HVS tests was to find out the effect of spring and overload to the rutting of the road. The tested structures had equal structures, which thickness was 500 mm on the sandy subgade. In the tests two different loadings (50 kN and 70 kN) were used and also the level of the water was changed from the depth of 1,0 metres to 0,5metres. The biggest part of the permanent deformations happened in the sand (subgrade) in the depth over 500 mm. The results showed that the rule of the fourth power is not valid for the low-volume road structures in spring conditions, but the rutting is much quicker than this law rule predicts. A clear growth in the deformations was detected once the elastic deforamtions corresponding to the certain stress state had crossed a particular threshold value. This means that the 'shakedown' value was crossed.