Moisture sensitivity of unbound granular materials

Shafiqur Rahman

One of the main structural units in thin flexible pavement is the unbound aggregate base course. It contributes to the overall load spreading mechanism of the structure due to traffic loading and provides an underneath support to the asphalt concrete layer. The material characteristic of unbound layers are therefore of great importance for the performance of the structure. Unbound base courses show stress as well as moisture dependent behaviour during external loading. This is true for both their stiffness and resistance against permanent deformation properties. A series of Repeated Load Triaxial (RLT) tests has been carried out on a typical unbound aggregate base layer to investigate its behaviour in order to improve the modelling of the moisture sensitivity. Both the resilient test and multi-stage loading approach have been used providing information on the resilient as well as the permanent deformation characteristics. Results showed that the stiffness decreases and permanent deformation increases with increasing moisture content.



Cost Benefit Analysis (CBA) workshop in Stockholm

An open seminar and workshop in Stockholm will be held on 25-26 April 2018. The workshop deals with the use of CBA as a basis for decision-making in the public sector. The workshop is organized by, among others, Professor Jan-Eric Nilsson, VTI.



Ulf Sandberg has been presented with the TTI Lifetime Achievement Award 2018

VTI’s Senior Research Leader Ulf Sandberg has been presented with the TTI Lifetime Achievement Award 2018 for his work on research into tyres and road surface.


Steps need to be taken to increase traffic safety of automated cars

Several steps are necessary to ensure that automated and connected cars will lead to increased traffic safety – everything from ensuring that technology takes vulnerable road users into account, to new forms of driver training. This has emerged in a position...


FALCON examines challenges in the transport sector

VTI is one of several important partners in the major FALCON project*, whose purpose is to create knowledge and insight regarding the transport sector. In an initial subproject, VTI has produced a manual on transport, logistics and multimodality.


VTI joined research cooperation in China

In December 2017 VTI became a member of China-Sweden Research Centre for Traffic Safety (CTS).


Swedish German research collaboration on Electric Road Systems

The project “Swedish-German research collaboration on Electric Road Systems” (CollERS) has now officially started. The goal of the project is to increase the common knowledge around Electric Road Systems by cooperation between Germany and Sweden and to...


Electric Road Systems Conference 2018

After a successful first conference in June 2017, the Swedish research and innovation platform for electric roads is arranging the second dedicated International Conference on Electric Road Systems (ERS) June 13th and 14th 2018.