Finnish Road Administration Is Working for Road Users

VOL. 10 / No. 1 April, 2002

Quarterly Newsletter of the Finnish Highway Transportation Technology Center, FinnT2

FINNISH ROAD ADMINISTRATION IS WORKING FOR ROAD USERS

THE FINNISH ROAD ADMINISTRA- TION (FINNRA) IS RESPONSIBLE FOR THE PUBLIC ROAD NETWORK IN FINLAND. ITS MISSION IS TO PROVIDE SMOOTH, SAFE AND ENVIRONMENTALLY FRIENDLY ROAD CONNECTIONS TO SATISFY THE TRANSPORT NEEDS OF CITI- ZENS AND BUSINESS LIFE ALIKE.

WORKING UNDER THE MINISTRY OF TRANSPORT AND COMMUNI- CATIONS OF FINLAND, FINNRA IS IN CHARGE OF OFFICIAL AND ADMINISTRATIVE TASKS IN THE FIELD OF ROAD MANAGEMENT. FINNRA DEVELOPS THE TRANSPORT A wintry motorway section belonging to Finnra’s responsibility. SYSTEM IN CO-OPERATION WITH OTHER ORGANIZATIONS AND PARTNERS. agency specifies quality criteria for the Some examples: it is now the tenth work and supervises compliance with annual volume in which the Finncontact THE ACTIVITIES OF FINNRA FORM A them. The contractor acquires materi- newsletter is appearing in English for BASIS FOR THE WELL BEING OF als, selects work methods and techni- our foreign colleagues. Winter traffic SOCIETY AT LARGE. SOCIAL DEVEL- cal solutions and is responsible for the and winter maintenance being particu- OPMENT LEADS TO MANY, AND outcome. lar Finnish know-how, this Finncontact SOMETIMES CONTRADICTORY, issue includes two abridged versions of EXPECTATIONS. THE GUIDELINES Customer (i.e. road user) satisfaction papers given by Finnish experts in the FOR ROAD MANAGEMENT AND is monitored through surveys. The World Road Association’s (PIARC) XI DEVELOPMENT 2015 PROVIDE results are utilized in developing the International Winter Road Congress in SIGNPOSTS FOR ROAD MANAGE- agency’s activities and services further. Sapporo, Japan, at the end of January MENT AND FINNRA’S ACTIVITIES IN this year. Altogether about dozen DECADES TO COME. Finnra provides road users with papers were given by Finns in the auxiliary services to ensure smooth Sapporo congress. Finnra supervises planning, construc- traffic flow.The agency disseminates tion and maintenance of the Finnish information about road and weather JARMO IKONEN public road network as well as draws conditions, traffic congestion, disrup- up investment plans in this respect. tions and recommendable routes. The agency’s tasks also include the promotion of a well-functioning market Finnra as an agency has defined in the road sector field. An efficient certain values of its own. The values Also In This Issue: market is conductive to the cost- adopted are: effective use of appropriations and ROAD WEATHER INFORMA- innovative road management. • Societal responsibility • Customer-orientated activities TION FOR ROAD USERS Finnra, being divided into a head- • Know-how quarters and nine road management • Co-operation. MINIMISING SALT CON- regions, commissions all road management products and services The Finnish Road Administration is SUMPTION ON GROUND through competitive bidding. The active in international co-operation, too. WATER AREAS

Address: Finnish Road Administration, FinnT2, P.O. Box 33, 00521 Helsinki, FINLAND. Fax: +358 20422 2322. E-mail: [email protected]. Editor: Arto Tevajärvi, Tel. +358 20422 2032. 1 Editor-In-Chief: Jarmo Ikonen, Tel. +358 20422 2118. ROAD WEATHER INFORMATION FOR ROAD USERS IN FINLAND

The Road Weather Information jointly by the Finnish Road Administra- warnings of poor road conditions. One Service is a Traffic Information tion, the Finnish Meteorological specific aim was to have distinct Service in Finland that started in Institute, the Central Organisation for warnings for days with the most danger- Traffic Safety in Finland, the Finnish ous conditions, which typically occur on the winter 1997–1998. The Motor Insurers’ Centre and the Finnish 5 to 10 days every winter. service provides drivers with Broadcasting Company. Service is continual forecasts on road and based on Finnra’s information on road weather conditions in winter in conditions and knowledge of mainte- EVALUATION OF THE ROAD order to improve traffic safety. nance operations, combined with WEATHER INFORMATION weather information from the Meteoro- SERVICE The forecasts are based on logical Institute. road conditions, weather and The service was evaluated to study maintenance actions. The The Road Weather Information how well the objectives of the Road information is presented in a Service sets three levels for conditions Weather Service have been met. The on main roads: “normal”, “poor”, and studied issues were: how well do systemised way on national drivers know the service and their television and radio in connec- “hazardous”. Road weather forecasts were added to the national weather opinion of it, correctness of Road tion with weather forecasts. The forecasts starting on 1 October and Weather Information, difficulties and service has established its are compiled three times a day: early problems producing the service and position as a source of informa- morning, forenoon and afternoon. The the experts’ opinions on the service. information is presented for each of tion for road users – 9/10 The evaluation was conducted with recognise the service, and the the 19 provinces, thus it is an overall description of road conditions. various methods, including interviews effect on drivers’ behaviour is of car drivers, evaluation of the estimated as large. forecasts with log sheets, comparison “Normal road conditions” indicates with the numbers of accidents and light snowfall that is not expected to forecasted Road Weather classifica- continue. The “normal conditions” are INTRODUCTION slightly different in different areas of the country. In “normal” conditions in Traffic information relating to weather southern parts of Finland the main and road and traffic conditions is an roads are relatively bare; further north area under constant development by road surfaces can often be worn into the Finnish Road Administration grooves by the passage of vehicles. (Finnra). Despite the continuous Road weather is “poor” when there is improvement of winter road mainte- heavy snowfall or snowfall is expected nance, hazardous road conditions in to continue for a long time, visibility is winter cannot be avoided entirely and clearly reduced because of the snow, drivers must occasionally cope with or changing temperatures cause bad conditions. The risks drivers face slipperiness. Conditions are “hazard- in adverse weather conditions in ous” when freezing rain causes Finland are many times those encoun- slipperiness that cannot be prevented tered on a bare road surface. For through maintenance, or when the example, in one study it was estimat- snowfall is so heavy that roads cannot ed that the risk between different road be adequately ploughed. The “normal conditions in Finland can be classified conditions” are not actively presented as follows: bare 1, snow 9, slush 12 in the forecast, only the “poor” and and ice 17. The large variance in risk “hazardous” conditions are. Figure 1 figures shows that drivers do not presents an example of how the Road adapt their behaviour well enough in Weather Information is presented on different conditions. television.

ROAD WEATHER The primary aim of the Road Weather Classification of Road Weather Information is to provide drivers with Information INFORMATION SERVICE continual updates on road conditions = Normal winter road conditions for improving safety. With the help of The Road Weather Information = Poor road conditions the service the drivers can also estimate Service provides drivers with forecasts = Hazardous road conditions on road and weather conditions in the conditions in advance and thus winter between October and March. adapt their travel behaviour. The service Figure 1. Example on Road Weather The service has been developed also aims at reducing the number of Presentation on television.

2 tion and also by interviewing various situations had been forecasted on as a source of information on road experts on the area. These different days with a high number of road conditions and forecasts on road methods were used to tackle various accidents. Based on findings from conditions – 90% of the interview- issues of interest. Various sets of earlier years it was estimated that ees recognised the service and a methods have been used since the roughly 5–10 days per year would vast majority of them claimed that start of the service so that more focus have close to double the average they get the Road Weather Informa- was naturally put into the early years daily rate of accidents. Some tion almost daily. Most drivers found of the service. winters have seen even more days the frequency of broadcasts on road that this, with 15 in 1995. conditions to be adequate and the Interviews of Car Drivers effect of the Road Weather on their The service has been evaluated after The days were divided into three own driving behaviour was said to each winter to see the effects of the categories depending on the daily be marked. For example, 63% of service. The main result was that the number of accidents. The day was drivers after winter 1997–1998 service was very well recognised classified as “normal” if the number answered that the road weather already after the first winter: 87% of of accidents was below the aver- information had a strong or very the interviewees recognised the age + 20%. The accident number marked effect on the time they service in two independent studies. was “high” when there were more reserve for travel, and 71% said has After three winters of the service, 90% accidents than 80% above the a strong or very marked effect on of interviewees recognised the average. Such days were also their driving behaviour. These results service. called “peak days”. Between these indicate that the Road Weather two categories, the accident Information affects not only drivers’ The road users estimated that the effect number was categorised as “some- comfort but also traffic safety. of the Road Weather Service on their what higher”. The comparison with own behaviour was notable (Figure 2). the number of accidents in each In conclusion it can be said that the For example, after the first winter 63% Road Weather categories “normal”, Road Weather Information Service of interviewees said that road weather “poor” and “hazardous” and the achieved a fair degree of success had a strong or very strong influence respective accidents in these already in its first winter. The on their time reserved for the journey. conditions showed that there service was well known among car Furthermore, 71% of interviewees said occurred clearly more accidents drivers and the effects were estimat- that the information had an influence when “poor” conditions had been ed to be large. The quality of the on their driving. Between 20% and forecasted. This result was even service also has been improved 70% of subjects answered that the more evident in the case of “haz- during the years of its operation. service had a “marked or very ardous” conditions. These findings The positive results of Road Weath- marked” effect on their behaviour on show clearly that the service pro- er Information contributed to the all the presented issues. vides adequate information to the development of “road conditions” difficult driving conditions. The information directed to pedestrians. Women answered more often than weather situations for the “peak This new service was tested in the men that the Road Weather Informa- days” are being studied after each Helsinki region in Finland and it got tion Service had an effect on their winter to further develop the quality very high acceptance especially behaviour. This trend was observed in of information. among the elderly people. The all the answers to this part of the problem of slipping accidents is a questionnaire. When asked whether significant socio-economic problem they had benefited from the new road CONCLUSIONS OF in Finland. traffic information compared with the EVALUATION STUDIES regular national weather forecast, The Road Weather Information The evaluation results showed that around 75% of drivers responded that Service has been operating since the users feel that the service is they had. Professional drivers felt more 1997. It has established its position important and they claim to use it in often than others that they had benefited from the service

The estimated effects of the Road 20 % Choice of travel mode Weather Information Service were Changing to summer 53 % often greater than in previous studies or winter tyres covering various traffic information Time reserved for 63 % types. For example, in this study the travel service was said to have a strong or Choice of time of 51 % departure very marked effect on the time re- 24 % served for travel (63%) and on the Route planning 35 % driving behaviour (71%). The respec- Comfort of travel tive figures in an earlier study were Driving behaviour 71 % 42% and 58%. (speed etc.) 0 % 10 % 20 % 30 % 40 % 50 % 60 % 70 % 80 % Road Weather Information and Persons who recognised the service, n = 810 Days with High Numbers of Accidents Marked Some Very slight None Don't know The aim was to study how well very Figure 2. How great an effect has the Road Weather Information Service had on your difficult road conditions and weather driving behaviour?

3 wide extent. The accuracy and fast content” for example, for in-vehicle ardous. This will be done during the distribution of the information are information systems, even though it winter 2001–2002 and the main important so that the people will should probably be modified to object is to study how the information benefit from these kinds of informa- cover smaller areas etc. This is actually affected the road users. tion services even more when especially true in the situations and making their travel decisions. Road areas where the changes of weather For more information, please contact Weather Information is now widely are difficult to forecast. Also, the Magnus Nygård, Finnish Road distributed through radio and time span of 24 hours, even though Administration / Traffic Services, television. In current situation, these the changes during this period are P.O.Box 33, FIN-00521 Helsinki, are the two main channels for reported, is quite long, which makes Finland, tel. +358 20 422 2423, information provision, but in the it desirable to develop more local fax +358 20 422 2418, future it is likely that this kind of forecast services that concentrate [email protected]; or information will be broadcasted to more in the next couple of hours. Jorma Helin, Finnish Road Adminis- the road users’ vehicle. However, the overall picture of Road tration / Traffic Services, Weather Information will be valua- P.O.Box 33, FIN-00521 Helsinki, ble for road users in the future also. Finland, tel. +358 20 422 2520, fax +358 20 422 2418, FUTURE One next step in the near future is to [email protected]. The Road Weather Information study on site the effects of Road Service will be in operation every Weather Information in the situations Mr. MAGNUS NYGÅRD, Finnra and winter. It can be seen as a “real when the road conditions are haz- Mr. JORMA HELIN, Finnra

MINIMISING SALT CONSUMPTION ON GROUND WATER AREAS

1. INTRODUCTION in the experiment. The purpose of this 3. EXISTING GUIDELINES experiment was to determine what the The Uusimaa Road Region began the FOR CONTROLLING chances are of reducing salting for experiment on reducing salting for SLIPPERY CONDITIONS ON preventing slippery conditions, as well controlling slipperiness in the 1999 as how the reduced use of salt affects THE ROADS IN THE autumn. A reduced amount of salt is the chlorine concentration of ground- EXPERIMENT applied in particular when freezing water, road safety, the speed adopted weather is growing warmer, causing by traffic, and feedback from road Salting should be reduced on roads in a thin layer of ice (frosting) to form on users. In addition, the changes groundwater areas. the road surface and a slight increase required in other control of slippery in slipperiness. The use of salt for conditions when making reductions in For the salt reduction experiment a preventing slipperiness following a the amount of salt were studied. lower friction requirement (0.25) snow storm is also being reduced in than normal (0.30) is accepted. the experiment. Skidding is effectively eliminated 2. GENERAL GUIDELINES below a friction level of 0.25. Slippery conditions resulting from a FOR WINTER ROAD Friction values of less than 0.20 are damp, warm road freezing are, not acceptable. however, being controlled on the MANAGEMENT IN FINLAND roads in the experiment by normal According to the general requirements In addition to the daily weather and salting. Similarly, slipperiness due to set for winter maintenance, the road condition forecasts serving the supercooled rain is being managed freezing of wet road surfaces is also needs of road maintenance, 2-3 day by applying salt in the normal way. prevented by pre-salting before and forecasts are prepared. It is particular- after the actual winter period (11.12.- ly important to take temperature On the roads chosen for the experi- 15.3.) in surface frosting and road changes into account when the ment the new maintenance practices conditions where there is no precipita- weather is growing warmer after a were assessed as reducing the use of tion. For this purpose, soluble salt is bout of frost. Also, as the temperature salt by 20 - 30 % compared to used, as on other roads. continues to fall, it is important to previous salting. According to the contact road maintenance teams to normal salting practice, 7.5 - 10 tons Figure 1 and Figure 2 gives the give them time to eliminate any more salt per road kilometre is used general requirements for preventing packed snow before the road surface on roads equivalent to those included slippery conditions: becomes colder.

4 The correct timing of salting is extremely important. An attempt should QUALITY REQUIREMENTS FOR CONTROLLING SLIPPERY CONDITIONS be made to carry out salting before Winter care Is I Ib II III K1 K2 traffic uses the road, so that a good category result is obtained even with a small Normal 0.30 0.28 0.25 according to according to according to amount of salt. In autumn and spring, traffic traffic traffic problems arising due to black ice requirement requirement requirement should be resolved using soluble salt Friction road surface road surface point gritting by precisely predicting the weather requirement under under 0.25 -6ºC-4ºC route conditions. Road condition forecasts 0.25 0.25 application in this kind of situation are in a key 0.20-0.22 position. The amount of salt used for At night 22.00 hrs 22.00 hrs 22.00 hrs 22.00 hrs 06 22.00 hrs 06 after 2200 hrs dealing with black ice per application 05.00 hrs 05.00 hrs 05.00 hrs should be only 2-5 gr/sq.m. 0.28 0.25 as required as required as required K1 05.00 hrs K2 When frost forms on the road surface, by the friction values must be carefully 06.00 hrs followed. No salting is carried out From start of 2 h 2 h salt 3 h 6 h 10 h 2 h unless the situation looks as though the procedure grit 4 h route gritting route gritting friction value is going to drop below 0.25. In this kind of situation, there is a Figure 1. Quality requirements for controlling slippery conditions in Finland. real risk of road junctions becoming slick. Road junctions should be main- Friction value 0.00 - 0.14 0.15 - 0.19 0.20 - 0.24 0.25 - 0.29 0.30 - 0.44 0.45 - 1.00 tained on an individual basis, by either Description of dangerous icy compacted coarse bare and wet bare and dry salting or grit application. Slippery road surface conditions, snow and ice compacted conditions should only be dealt with i.e. wet ice ice and snow where a definite need exists. During a extremely slippery satisfactory good good good frosty spell, road junctions should be slippery winter winter friction conditions managed by gritting. In awkward conditions conditions situations, small amounts of CaCl2 solution can be used. The aim is for a Figure 2. Reciprocity of friction value and road condition. maximum of 5 t of salt to be applied per road kilometre. Finland in the formations typical to accidents, which is exactly the same groundwater areas generally fall level as in the 1996-97 and 1997- 4. MONITORING THE SALT below 10 mg/l. 98 winters. By contrast, 25 accidents CONCENTRATION OF occurred during the 1998-99 winter, GROUNDWATERS which is a markedly higher number 5. CHANGES IN ROAD CARE than in other winters, even though the As the aim of the experiment is to On the roads in the experiment it was traditional maintenance practice was prevent a rise in the concentration of possible to reduce the use of salt by used at that time. This large number of chlorine in groundwater, groundwater 40% compared to the average use in winter accidents was due to excep- quality monitoring is one of the main previous winters. On these roads an tional weather conditions. tasks of the experiment. average of 5.5 tons per road kilometre were used. Previously 10 tons/road Limit of chlorine concentration in km have been used on these roads. 7. CHANGES IN THE household water AVERAGE SPEED OF TRAFFIC A limit has been placed on the chlorine The costs of winter maintenance in On the roads used for the experiment concentration of household water for total have not decreased on the roads there are three points at which the technical-aesthetic reasons. In Finland, in the experiment because it has been speed of traffic is continuously record- the limit set by the Road Administration necessary to control slipperiness in ed. Over the 1999-2000 winter for chlorine is 100 mg/l. Should this other ways in proportion to the period the monthly average speeds of level be exceeded, compensation has decrease in salting. The real benefit is the traffic have been compared with to be paid to the consumers of the obtained from the groundwater salt those of previous years. Changes in water. If the chlorine concentration concentration over the long term speed are extremely small. The lowest exceeds 25 mg/l, a study is undertak- remaining at a lower level compared average speed for any one month was en to determine whether road salting is to a continuation of previous mainte- 82.9 km/h, the highest average affecting the chlorine concentration of nance practices. speed being 95.5 km/h. On aver- the groundwater. The limit set by the age, the average speeds during the World Health Organisation (WHO) is 1999-2000 winter have decreased 250 mg/l, this value having been set 6. ACCIDENTS by only 0.1 km/h. The change is on the basis of taste. The high level set The total number of accidents under insignificant when one takes into by WHO is most likely a consequence winter road conditions were counted account that changes of less than 0.5 of the groundwater in many hot from the beginning of October to the km/h fall below the measuring accura- countries being appreciably salty. end of April. When the accidents cy of the equipment used for recording Concentrations of over 250 mg/l occurring in the 1999-2000 winter speeds. One can thus state that the make household water rather unpalata- period are examined, it can be speeds adopted by traffic have not ble. Natural chlorine concentrations in observed that there were 14 such changed during the experiment.

5 produced some encouraging results in The chlorine concentration in groundwater wells alongside the roads used for the experiment the 1999-2000 winter period. 40 During the first year of the experiment the chlorine concentration of ground- 35 water has decreased on average by 30 1.36 mg/l.

25 It proved possible to reduce the amount of salt by about 40% com- 20 mg/l pared to the average for the previous 15 winters. An average of 5.8 tons of salt was used per road kilometre. Other 10 control of slippery conditions has had to be resorted to in order to compen- 5 sate. No change is detectable in the number of accidents compared to the

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Hyvink period, certain roads parallel to TAMMISAARI/Bj motorways were incorporated in the Figure 3. Fluctuations in the chlorine concentration in groundwater wells alongside the experiment. This experiment is aimed roads used for the experiment. at offering motorists an opportunity to use roads on which less salt than normal has been used. Groundwater quality monitoring, the monitoring of 8. FEEDBACK FROM ROAD Use of salt road safety, traffic speed monitoring, USERS AND IMPARTING OF 2,5 INFORMATION and the gathering of feedback from 2,0 motorists will also continue; opinions In conjunction with the experiment, will also be sought and changes in feedback from motorists was gathered. 1,5 road maintenance will be deter- The information received contained mined. nothing at all directly connected with 1,0 the experiment. It can thus be conclud- t/km/month This experiment also constitutes a ed that the salt reduction experiment 0,5 learning process for those personnel carried out in the 1999-2000 winter using salt; salt does not need to be period caused neither a negative nor a 0,0 used in the quantities which they have Oct Nov Dec Jan Feb Mar Apr positive reaction among the road grown accustomed to. users, at least to the extent that some- Figure 4. Monthly use of salt on the roads body or other would have bothered to used for the experiment. Mr. SEPPO MÄKINEN, Finnra provide feedback.There was a second questionnaire in March 2000. This was directed at those road users who use those roads that are parallel to motorways and on which salting had been reduced in the 2000-2001 winter. The purpose of this questionnaire was to discern whether people were aware that salting had been reduced on these roads, and what their opinions were on the matter. Almost all the respondents had been driving either passenger cars or vans. The use of salt was widely criticised. Approximately one driver out of three expressed the hope that salting would cease completely. Around 30% of the respondents did not want little used roads to be salted at all. Most of them felt that salting should be reduced.

9. FINAL CONCLUSIONS The reduction in the salting experiment Figure 5. Road users were warned of slippery conditions by means of road signs.

6 THE USE OF GLACIAL CLAY IN PROTECTION OF THE MOST IMPORTANT GROUNDWATER AREAS

1. BACKGROUND will have to be examined at the on Highway 6 over a distance of 1.5 Railroads and highways in Finland are extraction site of the soil. In this study km in 1996. Sand bentonite (fine- often built on areas of glacial sand the suitability of glacial clay as grained sand mixed with 4 % of and gravel. These areas are also the protective material of groundwater bentonite clay) was used as the location of most of the important has also been examined with the help protective material. The groundwater groundwater areas, the water reserves of test construction, a follow-up study protections were constructed on the of which are utilised by municipalities, and as a ‘real construction site’. slopes of the highway, so that the protections reached at a distance of 9 cities and industrial plants. The Finnish 2.1. Laboratory tests Road Administration (Finnra) uses meters from the edge of the pavement approximately 10-12 tons/km of salt The samples taken from the extraction of the carriageway. At the same time a (sodium chloride) annually for the site of glacial clay (in Utti and Jurvala) groundwater protection test-target area winter (November-March) maintenance show that the grain composition of the of 200 m in length was constructed of of highways. Another risk for ground- clay material is lean clay with a fine- Utti glacial clay. Figure 2 shows a waters, for which there has been grained material content of 32 %. The cross-section of the test-target area and concern about, is the transportation of other technical properties of the clay the compaction of the clay material. dangerous goods, which has in- material examined are: water content creased by approximately 20 % during 17-32 %, optimal water content 17 Figure 3 shows a structural drawing of the last ten years. Over 300,000 tons %, organic impurity 0 %, maximum the test structure. The thickness of the of dangerous goods are transported dry density 1.80 tons/m3. The clay mineral liner of glacial clay at the test- on a main road in Southern-Finland material is so-called dry crust clay, the target area is 500 mm or 700 mm annually. water content of which is relatively and the thickness of the protective layer low, approximately 25 %. on top of it is approximately 400 mm. According to the guidelines for the The uppermost layer is a grass-covered Figure 1 shows the quality require- 100 mm thick layer of soil. There are protection of groundwater of Finnra ments set for compact structures of soil (1993), glacial clay material may be 6 separate test structures in all: by the guidelines of Finnra (1993) for used as protective material of ground- the protection of groundwater as well 1) mineral liner of glacial clay 500 water. According to the new guide- as the properties of the Utti and lines (Draft 2000) only geosynthetic mm Jurvala glacial clay. The figure shows clay liners (GCL) or soil bentonite may 2) mineral liner of glacial clay 700 that, as far as the laboratory specifi- mm be used for ‘demanding chloride cations are concerned, the quality protection’. Thus glacial clay may not 3) mineral liner of glacial clay 500 requirements are clearly met: the fine- be used because it is feared that the mm + 100 mm of turf on top grained material content is 92 % and 4) mineral liner of glacial clay 700 clay material will dry in summer and the value of permeability to water is freeze in winter and the resulting mm + 100 mm of turf on top 1,000 times lower than the base cracks will clearly increase the 5) mineral liner of glacial clay 500 value. Also at the soil extraction site permeability of clay to water. mm + 50 mm of saw dust on top the clay material is homogenous in its 6) mineral liner of glacial clay 700 grain composition and quality. In the R&D project of the Finnish Road mm + 50 mm of saw dust on top. Enterprise it is examined by laboratory 2.2. Test construction tests and field experiments as well as The studies showed that the compact- Groundwater protections were con- in a ‘real construction site’, the ness of the mineral liner (glacial clay) structed in the Utti groundwater area suitability of glacial clay for ground- at the time of constructing the test target water protection material. The project started in 1996 and continues at least till 2003. The results of this project Property Quality requirements Utti/Jurvala glacial clay can be exploited to road slope protection and dumping place Fine-grained material content protection construction. (percentage passing through a 0.074-mm sieve) >70 % 92 % Modified Proctor density >85 % 90 % 2. EXISTING STUDIES Value of permeability to water (k-value) in the laboratory (modified According to the guidelines of Finnra -8 -11 (1993) for the protection of ground- Proctor density 90 %) <5 x 10 m/s 7 x 10 m/s water, the suitability of a mineral liner Value of permeability to water -6 -8 (glacial clays, moraine) as protective (k-value) in the field <5 x 10 m/s 3 x 10 m/s material of groundwater will be Homogeneity of mineral liner (no sand examined in laboratory tests. Also the layers, stones or plant waste) Yes Yes homogeneity and amount of the Figure 1. The quality requirements of mineral liners (Finnra,1993) and the properties of material to be used as a mineral liner the Utti and Jurvala glacial clay.

7 slope of the road was approximately 700 mm.

3. FURTHER STUDIES A new test site was built in the Utti groundwater area in the autumn of 2000. 30 meters long test structures were constructed in the slopes of Highway 6 by using the following materials as the impermeable layer: geosynthetic clay liner (GCL), sand bentonite and glacial clay. These test structures are monitored for temperature, moisture, and water permeability. Permeability is resolved by electrical conductivity measurements. Pressure sensors are used to measure the height of the water column above the bottom of the ditch. The aim of these tests is to study temperature related behaviour (freezing/drying) of the materials and to clarify the differences in their permeability. The results will Figure 2. Construction of the Utti glacial clay test-target area in August, 1996. The be reported in the autumn of 2002. compaction of the clay material was done with an excavator scoop. The groundwater protection of the edge of the pavement (inner slope of the road) was made by using the GCL visible in the picture (light-coloured strip). 4. SUMMARY Laboratory tests and field experiments, as well as a ‘real construction site’, Grassing, 100 mm be used for groundwater protections were utilized in this study to make Protective liner, 400 mm of ‘demanding chloride protection’, clear the suitability of glacial clay for (gravel and sand) because it is feared that the clay groundwater protection material. material will crack due to drying in Based on the results, the clay material Peat, 100 mm/sawdust, 50 mm/ summer and freezing in winter and ”without this leyer” found in the area of Salpausselkä I thus the values of permeability to and the moraine area (Utti and Mineral liner, 500/700 mm water will become high. This issue (glacial clay) Jurvala) is suitable also for protection has, however, not been sufficiently of the most important groundwater studied. areas. The clay is homogeneous and Filter sand, 50 mm has sufficiently low permeability. No Plastic geomembrane, 1.0 mm In November, 1998 a total of 16 freezing during winter or drying Geotextile temperature sensors and 6 humidity during summer was observed in the sensors were installed in 6 separate clay liner; thus, no fracturing occurs in Figure 3. Cross-section of the test structure test structures at the Utti test target for groundwater protection at Utti. the clay. Expenses for the use of area. The temperature sensors were glacial clay as groundwater protec- installed so that 3 sensors were tion material are only about 40 % of placed at different depths in each of the expenses of geosynthetic clay the 500-mm mineral liners and 2 liner. Also, the clay provides better area was approximately 90 % of the sensors in the 700-mm mineral liners. protection in accident situations that dry unit weight achieved through Additionally one sensor measured the involve transports of hazardous modified Proctor density and the value ambient temperature. substances. of permeability to water was approxi- -8 mately 3 x 10 m/s. These values are The winter follow-up study (25 No- For more information, please contact clearly better than those suggested as vember 1998 – 13 April 1999) Pekka Vallius, Finnish Road Enterprise, threshold values in the quality require- showed that no freezing occurred in P.O. Box 2000, FIN-45101 Kouvola, ments of Finnra (Figure 1.) the mineral liner of glacial clay. When Finland, tel. int. +358 204 44 the ambient temperature was at its 6373, fax int. +358 204 44 6371, 2.3. Follow-up studies coldest, at –30.5 °C (8 February e-mail: [email protected] According to the new guidelines of 1999), the temperature of the clay Finnra (Draft 2000) for the protection material was over 0 °C. In February Mr. PEKKA VALLIUS, Finnish Road of groundwater, glacial clay may not the thickness of the snow cover on the Enterprise