The Road Structures Research Programme (S4) was carried out in 1994-2001 by the Finnish Road Administration. The main part of the program consisted of the Road Structures Research Project (TPPT project) consisting development of pavement and the substructures. The objective of the results obtained from the TPPT project is to be able to construct new roads and repair old paved roads more durable while reducing the annual cost of the road. The goal of the TPPT project was to develop the design methods of the pavements to make them more durable and to make it possible to estimate their performance during their entire life span. If the performance of the road structures can be estimated in advance, the risk of unexpected damages decreases.

The results of the TPPT project were compiled into a design system. The design guidelines and descriptions of the design system present the procedures and methods with which a pavement for a particular site can be designed to keep settlement, frost damage and load-bearing capacity under control. The TPPT design system also includes a procedure for estimating the life cycle costs of alternative pavements.

The focal point of research in the TPPT project was on the pavement solutions and design of new high-volume roads. However, during the course of the research programme the emphasis of road management changed significantly from new road construction to maintenance of existing roads. As a result, a separate project concentrating on thin pavement roads was started alongside the TPPT project. At the same time the TPPT project was reduced down slightly.

Several projects with parallel, but more limited goals than the TPPT project were implemented alongside the TPPT project:

• Sustainable development structure idea competition
• Settlement calculation competition
• REFLEX steel mesh project
• Use of industrial by-products and development of life cycle assessment
• Instrumented test road in Temmes
• Thin pavement road project
• Damages of road structure and the condition of the road network

When the focal point of road management changed, the relative significance of these projects increased toward the end of the Road Structures Research Programme.

The programme produced a lot of publications. A great majority of them have been written in Finnish language, but all published reports have an English abstract and most of them can be opened on the 'Publications'  web page of the programme (in Finnish). 

The list in English will be found e.g. from the summarising report of the Road Structures Research Programme. Finnra Reports 37/2002 (pdf 3600k). The content of the programme and main results of some projects have been described very shortly in different chapters of that report.

Publications in English
A couple of papers belonging to Road and Structures Research Programme TPPT and to its supporting projects have been published in English. These are:
 
Symposium Proceeding. TPPT symposium 8-9 June 1998.
147 p.
Ulla-Maija Mroueh et.al.
Life cycle assessment of road construction (pdf, 270k). Finnra reports 17/2000. Helsinki 2000. 60 p.
Matti Huhtala, Jari Pihlajam�ki.
HVS-NORDIC. The activity of the first period in Finland 1997 - 1999 (pdf, 395k). Finnra reports 21/2000. Helsinki 2000. 59 p.
Heikki Kangas, Heikki Onninen and Seppo Saarelainen:
Testing a pavement on thawing, frost-susceptible subgrade with the heavy vehicle simulator (pdf, 2600k). Finnra reports 31/2000. Helsinki 2000. 67 p.
Pihlajam�ki, J. & Siki�, J.
HVS-NORDIC. Research Report No 2. Tests 9-10, high trafficked pavements on Ring Road II. Finnra Reports 29/2001
Huhtala, M., Pihlajam�ki, J. & Siki�, J.
HVS-NORDIC. Research Report No 3. Tests 1-2, base course tests, 03-05 loading mode tests i Otaniemi. Finnra Reports 30/2001
Koskinen, M., Veps�l�inen, P. & Lojander, M.
Modelling of anisotropic behaviour of clays. Test embankment in Murro, Sein�joki, Finland. Finnra reports 16/2002 (pdf 5660)

up