Influence of moisture on Resilient Deformation behaviour of Unbound Granular Materials

This study investigated the influence of moisture on the Resilient Deformation (RD) properties of Unbound Granular Materials (UGMs). A typical UGM used in pavement constructions with three different grain size distributions were tested with a range of moisture contents using Repeated Load Triaxial tests (RLTTs). From the European standard, the procedure for the study of the RD behaviour was used where each stress path is applied for 100 cycles. Additionally, the Multi-Stage (MS) loading procedure for the study of the permanent deformation behaviour were used where each stress path is applied for 10,000 cycles, to compare the results using the two test procedures. Results showed that resilient modulus (MR) generally decreased with increase in moisture, where the finer grading was more affected. However, for the MS RLTTs, after a large number of load applications, some increase in MR with increasing moisture was observed. This happened when the moisture content increased up to close to the optimum; above the optimum, MR always decreased. This may be due to Post-Compaction (PC) aided by moisture in MS RLTTs where a large number of load cycles were applied.



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.



Automation and digitalisation are making rail competitive

Road transport is developing rapidly and its productivity has increased sharply. Rail transport, however, has not developed at the same rate. Automation and digitalisation are essential if rail freight in Europe is to survive.


New research is creating a driverless logistics chain

The research project Born to Drive has come up with a system that allows new cars to move, without a driver, from the production line out to the parking area prior to being transported elsewhere. The vision is to automate the entire logistics chain from...


VTI testing automation in EU project

VTI is leading a series of tests in a major EU project on automated driving. The first driving tests were carried out n a test track in Slovenia in December. The project will focus in part on acceptance among different groups in society, in part on...


Freight transportation on road and rail analysed

Freight transport accounts for a large proportion of the emissions, noise and congestion produced by road traffic. Transporting freight in larger but fewer lorries could reduce the problem. At the same time it might entail freight being diverted from more...


Millions for research into maritime transport and the environment

Maritime transport is a major source of emissions of harmful air pollutants and carbon dioxide. In a new project, a research team from the Swedish National Road and Transport Research Institute (VTI) and the University of Gothenburg has received SEK 6.4...


New research programme for more efficient travel

The Swedish National Road and Transport Research Institute (VTI) is playing an important role in a major new research programme to find radical solutions leading to fewer trips and more efficient travel, along with tools to enable better use of roads and...