Tires
Transcription
Tires
Forskning på støy og støv i Finland Heikki Tervahattu Trondheim 14 September, 2006 Heikki Tervahattu 1 Contents 1. (Experimental studies on factors influencing road dust generation) 2. The comparison of studded and friction tires in the road dust problem 3. KAPU-project: Studies on the impact of winter maintenance and springtime street cleaning on the road dust problem 4. VIEME-project: Studies on the impact of road surfaces and tyres on noise and dust emission and transmission Heikki Tervahattu 2 Road dust research performed At an indoor road simulator Experimental field studies Mobile air quality research laboratory At the Nokia proving ground Using data from air quality monitoring stations Heikki Tervahattu 3 1. Experimental studies on factors influencing road dust generation Heikki Tervahattu 4 Publications Kupiainen K., Tervahattu H., and Räisänen M., 2003. Experimental Studies about the Impact of Traction Sand on Urban Road Dust Composition. The Science of the Total Environment 308, 175-184. Kupiainen K.J., Tervahattu H., Räisänen M., Mäkelä T., Aurela M., and Hillamo R., 2005. Size and Composition of Airborne Particles from Pavement Wear, Tires, and Traction Sanding. Environmental Science & Technology 39, 699706. Tervahattu H., Kupiainen K.J., Räisänen M., Mäkelä T., and Hillamo R., 2006. Generation of Urban Road Dust form Anti-Skid and Asphalt Concrete Aggregates. Journal of Hazardous Materials 132, 39-46. Kupiainen K. and Tervahattu H., 2004. The Effect of Traction Sanding on Urban Suspended Particles in Finland. Environmental Monitoring and Assessment 93, 287-300. Räisänen M., Kupiainen K., and Tervahattu H., 2003. The Effect of Mineralogy, Texture and Mechanical Properties of Anti-Skid and Asphalt Aggregates on Urban Dust. Bulletin of Engineering Geology and the Environment 62, 359368. Räisänen M., Kupiainen K., and Tervahattu H., 2003. The Effect of mineralogy, texture and Mechanical Properties of Anti-Skid and Asphalt Aggregates on Urban Dust, Stages II and III. Bulletin of Engineering Geology and the Environment 64, 247-256. Heikki Tervahattu 5 2. The comparison of studded and friction tires in the road dust problem Heikki Tervahattu 6 Tires Studded tire Summer tire Nokian renkaat Z Heikki Tervahattu Friction tire Nokian renkaat Hakkapeliitta Rsi 7 Nokian renkaat Hakkapeliitta 4 Wear of road/street surface On a clean road, studded tires generate much more PM10-dust. Friction tires wear only little clean asphalt surface. Several factors have an impact (weather conditions, the quality of the pavement, driving speed, the quality and amount of studs; wet pavement is weared much more than dry surface - salting has a great impact by keeping surfaces wet. etc.). Road surface is never clean. Mineral dust is generated by studs, from traction sand and transported by wind and cars from unpaved parking plots, yards, footways etc. Picture: Sand is transported from unpaved byways. Heikki Tervahattu 8 Sanded road/street • Regardless of the tire type, PM10-concentrations increase several fold when traction sand is used. • Asphalt wear is substantially enhanced by the sandpaper effect. Similar impact is caused by all hard materials on road surface. • Studs do not have great contribution in the sandpaper effect. The interaction of the whole tire surface with loose material and road surface is decisive; similarly the grinding of sand to inhalable dust is performed by the whole tire surface. • Friction tires and studded tires act similarly in grinding sand and in the sandpaper effect and their combined impact is much greater than asphalt wear by studs. Therefore friction and studded tires do not have great difference in PM10-production on sanded or otherwise dirty roads. Heikki Tervahattu 9 Resuspension • Air quality is finally dependant on the suspension of inhalable dust from the road surface. • Due to uneven road surface, some amount of dust is always layed on roads. • Under dirty conditions, resuspension is much greater than primary emission of road dust generated by direct road wear. • Are there any differences between friction and studded tires in resuspension of this dust? Heikki Tervahattu 10 • Road dust is always layed on uneven surfaces that are difficult to clean (SMA-asphalt, scale circle diameter 30 mm). Resuspension by friction and studded tires • We have performed more than 50 tests on 5 different low-noise pavements +”normal” references studying road dust concentrations by the Sniffer using 3 tire types. • Friction tire caused in all tests much greater PM10concentrations than other tire types on all pavements and all seasons (results in the figure on 25 April, 2006). 25000 20000 15000 Kesä 11438 Nasta Kitka 10000 5470 5000 1615 Heikki Tervahattu 11 Keskiarvo Röykkä_W Röykkä_E Röykkä_ref_W Röykkä_ref_E Klaukka_W Klaukka_E Klaukka_ref_W Klaukka_ref_E Kolke_W Kolke_E Lippa_ref_W Lippa_ref_E Konalantie_S Konala_N Konala_ref_S Konala_ref_N 0 ”Suction pad” effect • It was concluded that resuspension of dust by friction tires is much greater than by studded tires. --- WHY? • The anti-slippery impact of friction tires is produced by great amount of lamells and softer rubber material. • When lamells touch the road surface, air between the lamells is pressed out. When lamells get unfastened, air is ”sucked” between the lamells. Loose PM is consequently lifted from the road surface and suspended in the ambient air. • We named this phenomenon as a ”suction pad” effect. Heikki Tervahattu 12 Concluding summary • Studded tires cause greater road surface wear than friction tires producing more inhalable dust. • Both tire types act in a similar way in grinding sand and in the sandpaper effect. This dust production is dominating during dust episodes. • Resuspension of dust has much greater impact on ambient air than current dust generation on dirty roads. • Friction tires cause greater resuspension than studded tires. • In urban driving, the total impact of studded tires and friction tires on air quality may be almost similar. Heikki Tervahattu 13 3. KAPU-project Studies on the impact of winter maintenance and springtime street cleaning on the road dust problem Heikki Tervahattu 14 Aims and objectives • Studies on the impact of winter maintenance and springtime street cleaning on the road dust problem, aiming to provide new information for reducing road dust. • Objectives - The effectiveness of present maintenance measures and cleaning facilities - Development and testing of new practices and facilities Heikki Tervahattu 15 Implementation • Studies on road dust is mainly performed by the SNIFFER vehicle, the mobile air quality research laboratory • All measures taken for winter maintenance and road cleaning are carefully registered • Comprehensive data of air quality and meteorology is collected by the Sniffer and environmental authorities to support conclusions, international data is exploited • The composition of road dust is studied • New methods, materials and facilities are tested Heikki Tervahattu 16 STADIA’s contribution to the KAPU- and VIEME-projects • the mobile laboratory Sniffer • particle mass PM10 is monitored by TEOM Tapered Element Oscillating Microbalance, Series 1400A, Rupprecth & Patashnick), 20 s running averages are saved every 10 s • total particle number concentration and number size distribution of 7 nm - 10 μm particles are measured by ELPI (Electrical Low Pressure Impactor, Dekati Ltd) with 1 s time resolution. In the future also PM2.5 and PM1 will be calculated from the ELPI results. • weather station (relative wind speed, relative wind direction, temperature and relative humidity) is located at the roof of the van at 2.9 m altitude Dust sample is sucked from behind the left tire • gps saves driving speed, driving route and local coordinates Heikki Tervahattu 17 30.8.2006 Liisa Pirjola Cities • • • • • • Helsinki Vantaa Espoo Tampere Riihimäki Kerava Heikki Tervahattu 18 Reduction of dust at Vantaa, spring 2006 20.04. Heikki Tervahattu 27.04. 19 04.05. 31.05. Reduction of dust at Vantaa, spring 2006 20.04. 27.04. 04.05. 31.05. Heikki Tervahattu 20 Analysis of Vantaa dust measurements Kielotie 32 Talkootie 37 μg/m3 Lummetie 27 Talvikkitie 35 Ratatie 34 keskiarvo 33 Tikkurilantie 37 Urheilutie 33 18000 16000 streets cleaned 6.4.-20.4. 14000 12000 salting 19.3. sanding 20.3. 10000 salting 23.-24.3. ja 5.4. 8000 no rains 22.4.-13.5. dust binding 21.4. rains 14.5.-26.5.(not 22.5.) summer tires 2.5. 6000 4000 2000 Heikki Tervahattu 21 30.5. 22.5. 11.5. 4.5. 27.4. 24.4. 20.4. 11.4. 22.3. 0 Analysis of Vantaa dust measurements Road dust and suspended PM - High concentrations of suspended PM10 after street cleaning Additional impact from long-range transport of field fire smoke 3 road dust mg/m Mean/Vantaa Tikkurilantie PM10Vantaa PM2,5Luukki 3 suspended PM μg/m 12 120 dust binding 21.4. no rains 22.4.-13.5. 10 100 Streets cleaned by 20.4. 8 80 rains 14.5.-26.5.(not 22.5.) 6 60 4 40 2 20 0 0 4.3. Heikki Tervahattu 9.3. 14.3. 19.3. 24.3. 29.3. 3.4. 8.4. 13.4. 18.4. 23.4. 28.4. 22 3.5. 8.5. 13.5. 18.5. 23.5. 28.5. 4. VIEME-project Rolling Noise Abatement - R & D Project • The impact of road surfaces and tyres on noise and dust emission and transmission • Emission and transmission of noise and dust are studied simultaneously and at the same locations • Better understanding of the connections of the two problems as well as the road-tyre interaction will be produced • The goal is to reduce exposure to noise without increasing dust problems and weakening traffic safety Heikki Tervahattu 23 Implementation • Emission and propagation of noise and dust are measured during different seasons at road and street strips having surfaces with different noise contribution • The transmission and distribution of noise and dust are studied also by models • The impact of different tyre types on rolling noise and dust emissions is studied at selected locations and on the proving ground • Researchers Heikki Tervahattu and Kaarle Kupiainen, Nordic Envicon Oy Panu Sainio, Helsinki University of Technology Tapio Lahti, Akukon Oy Mika Räisänen, Geological Survey of Finland Liisa Pirjola, Helsinki Polytechnic Leena Kangas, Finnish Meteorological Institute Heikki Tervahattu 24 Dust emissions from low-noise and normal pavements 1/4. • 16000 14000 12000 μg/m3 10000 ref 8000 hil 6000 4000 2000 Heikki Tervahattu 25 keskiarvo Riihi Röykkä Klaukka Lippa/kolke Konala 0 • • • • Sniffer measurements on April 13, 2006 Studded tyres ref = reference hil =low-noise keskiarvo= mean Dust emissions from low-noise and normal pavements 2/4. Kesärengas ref Nastarengas ref Kesärengas hil Nastarengas hil 9000 3500 8000 7000 6000 3000 2500 5000 2000 4000 3000 2000 1500 1000 1000 0 500 0 Konala Lippa/Kolke Klaukka Röykkä keskiarvo Lippa/Kolke Klaukka Röykkä keskiarvo Studded tyre Summer tyre Kitkarengas ref Konala Kitkarengas hil 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 Sniffer measurements April 25, 2006 Konala Lippa/Kolke Klaukka Röykkä keskiarvo Friction tyre Heikki Tervahattu 26 Dust emissions from low-noise and normal pavements 3/4. Kesärengas ref Kesärengas hil Nastarengas ref 3000 Nastarengas hil 7000 2500 6000 2000 5000 1500 4000 3000 1000 2000 500 1000 0 Konala Lippa/Kolke Klaukka Röykkä keskiarvo Pirkkola Summer tyre Kitkarengas ref 0 Konala Lippa/Kolke Klaukka Röykkä keskiarvo Studded tyre Kitkarengas hil 10000 9000 8000 Sniffer measurements May 3, 2006 7000 6000 5000 4000 3000 2000 1000 0 Konala Lippa/Kolke Klaukka Röykkä Keskiarvo Pirkkola Friction tyre Heikki Tervahattu 27 Pirkkola Dust emissions from low-noise and normal pavements 4/4. Kesärengas ref Kesärengas hil Nastarengas ref 1600 Nastarengas hil 3500 1400 3000 1200 2500 1000 2000 800 1500 600 1000 400 500 200 0 0 Konala Lippa/Kolke Klaukka Röykkä Keskiarvo Pirkkola Konala Summer tyre Kitkarengas ref 5000 4000 3000 2000 1000 0 Heikki Tervahattu Klaukka Röykkä Keskiarvo Kitkarengas hil • Lippa/Kolke Klaukka Studded tyre 6000 Konala Lippa/Kolke Röykkä Friction tyre Keskiarvo 28 Pirkkola Sniffer measurements May 31, 2006 Pirkkola Dust emissions from a low-noise and a reference pavement Heikki Tervahattu 29 Conclusions • • Differences in dust level between low-noise and normal pavements are varying and no clear tendency could be shown More intensive research is needed Hypothesis Having a smoother surface, low noise asphalt has smaller volume for depot of PM. It may be better cleaned by traffic, wind and rain as well as better cleanable by maintenance. PM emissions would thus be lower. Heikki Tervahattu 30 Noise and wear measurements by HUT* Panu Sainio 1. Noise from CPX alias trailer method with 3 tyres, 50km/h (normal summer, Nordic non-studded and studded winter tyre), 5 silent pavements +references 2. Wear measurements done by Lab. of Highway Engineering with profilometer from one old and well know test area *Helsinki University of Technology www.tkk.fi/units/auto NOTRA CPX-trailer Heikki Tervahattu 31 www.tkk.fi/units/auto 1. Noise emission -Tyre-road noise emission decreases during summer period with all types of tyres - Silent pavements do not lower stud-related noise -Type of tyre is more important than type of asphalt dB(A) - Noise emission from friction tyres much lower than from studded tyres and even lower than from summer tyres average values of different pavements with different tyres 99 avg stud silent avg stud ref 97 95 avg sum ref 93 avg sum silent avg fric ref 91 avg fric silent 5.8. 29.7. 22.7. 15.7. 8.7. 1.7. 24.6. 17.6. 10.6. 3.6. 27.5. 20.5. 13.5. 32 6.5. 29.4. 22.4. Heikki Tervahattu 15.4. 89 Wear measurements www.tkk.fi/units/auto - One aspect of the project is to follow older test sections from previous projects as for wear and noise - Silent pavement are made from "best available" material to gain max wearing resistance. The mass used for silent pavement 60 kg/m2 ~ for conventional AB16 100 kg/m2. mm autumn02 spring03 spring04 spring05 spring06 14 12 Collector road on residential area with average daytime traffic~4500 10 8 6 4 2 0 Heikki Tervahattu Hiltti-mix 33 SMA6 SMA8 ref AB16 ref Noise emission from aging pavement www.tkk.fi/units/auto • Old silent pavement (left), SMA 6 in the previous slide • Noise emission substantially lower than in the reference (right) with summer tyres Heikki Tervahattu 34 Noise emission & propagation Dr. Tapio Lahti, Akukon Oy • Measurement setup: – Pass-by – 4 simultaneous synchronised microphone channels (low, standard, high & far) – Full phase-locked signal information recorded for post-processing – In addition to standard measurements: • Nearfield radiation of emission • Vertical directivity • Close-distance propagation Heikki Tervahattu 35 Microphone positions High Heikki Tervahattu Standard 36 Far Low Basic measurements • Low-noise and reference pavements • Relation to standard methods: – – – – Common statistical pass-by (SPB) + Nordtest standard: determination of noise emission + Nordtest extension (under preparation) + EU Harmonoise: complement method for directivity of emission – + Determination of the ground attenuation of noise propagation Heikki Tervahattu 37 Special measurements • Nokia proving ground (normal pavement) – 3 types: summer, friction, studded – fully controlled conditions (e.g. geometry, asphalt surface & vehicle speed) – repeated single-vehicle coast-by with motor idling Heikki Tervahattu 38 Examples of pass-by time histories 100 AF sound level, dB low std high far passing by 90 80 approaching driving away 70 60 50 0 Heikki Tervahattu 5 10 39 15 time, s Examples of pass-by spectra 80 Aeq sound level, dB low std high far 70 60 50 40 30 100 Heikki Tervahattu 1000 40 frequency, Hz 10000 Some preliminary results • Basic noise emission: – absolute emission of the pavement test sites determined in terms of the Nordic noise prediction models • Additional information of emission: – spectrum and directivity of noise radiation • Comparison of tyre types: – the studded winter tyre is ”several” dB noisier than the summer and friction tyres Heikki Tervahattu 41 THANK YOU FOR YOUR ATTENTION ! Heikki Tervahattu 42 Mineralogy of the aggregates (2001-2002) Traction sands • • • • Minerals >5% presented in table Hornblende tracer Mineral size in aggregates 0.1-10 mm Mineral types identifiable in PM with individual particle analysis (SEM/EDX) Granites Heikki Tervahattu Diabase Mafic vulcanite 29.4 Quartz 30.4 K-feldspar 29.6 Plagioclase 32.4 57.4 Biotite 5.9 3.8 53 Hornblende Clinopyroxene 17.3 Olivine 17.5 CummingtoniteGrunerite 43 Asphalt 12.8 Individual particle analysis • Based on the analysis of individual particles by SEM/EDX. The chemical composition of particles is analysed and the mineral type of each particle is identified. Heikki Tervahattu 44 • The road dust particle in the photo was identified as potassium feldspar for its high content of K, Si, Al, and O. Composition of particles • >90% mineral particles, others: bitumen, tires, carbonates. • Hornblende (red) as a tracer, because the asphalt stone contained 53% hornblende (right column) and the sanding materials (left) did not contain it. All hornblende particles originated from asphalt – this was the basis for calculating the shares of asphalt and sanding material. • 100% ? 34 80% 33 19 60% 17 15 40% 14 13 12 20% 11 2 Heikki Tervahattu 45 asfaltti Ki0 Na0 Mna4 Mna2 Dlna2 Dki2 Dna4 Dna2 Arna2 Anna2 Aki2 Ana4 Ana2 Ämmässuo 0% The test conditions • Indoor road simulator (passenger car weight) • 2-5ºC, RH 50-75% • 59 tests (2001-2003) – – – – 48 with traction sand 11 without studded/non-studded speed (15-30 km h-1) • 28 tests with a new asphalt in 2003 Heikki Tervahattu 46 PM sampling • 2 Virtual-impactors (PM2.5-10 and PM2.5) • 2 SDI cascade-impactors (12 stages, 0.06-10.7 μm) • TSP and PM10 hi-vol samplers Heikki Tervahattu 47 Emission levels affected by (1/4): - amount of sand aggregate - sand aggregate properties The aggregate with the lowest resistance against fragmentation (Granite 1) caused higher emissions especially when more sand was dispersed -3 PM10 [mg m ] (Figure: only studded tests with 2/5.6 sand) 9 8 7 6 5 4 3 2 1 0 Other Granite1 y = 0.0026x + 0.1765 2 R = 0.688 y = 0.002x + 0.3566 2 R = 0.9335 0 500 1000 1500 2000 -2 Heikki Tervahattu Amount of traction sand [g m ] 48 2500 Sanding experiments in field conditions (1/2) Effect of traction sanding on PM emissions • • Sanded surface = 9 x clean Tire type seemed not to play a big role after sanding PM9 before and after dispersion of traction sand µg m -3 30000 25000 40 kph - non-studded 20000 40 kph - studded 50 kph - non-studded 15000 50 kph - studded 10000 70 kph - non-studded 5000 70 kph - studded Heikki Tervahattu 49 After Before After Before After Before After Before After Before After Before 0 Sanding experiments in field conditions (2/2) Effect of traction sanding on PM emissions • • • • Highest difference immediately after sanding (max 15x) 4 hours after sanding the difference had decreased substantially Emissions decreased as sand was swept aside by traffic Result in line with US studies where PM levels decreased to presanding levels 8 hours after sanding (Kuhns et al., 2003. Atm. Env.37, 4573-) PM9 at 40 kph after sanding (15:28 and 18:40 tests with studded tires) 20000 Before sanding After sanding µg m -3 15000 10000 5000 0 14:11 14:55 15:28 16:57 Start time Heikki Tervahattu 50 18:10 18:40 Studies on the sources of the particles • Sanding increased PM from asphalt: indication of the abrasive wear of the pavement by sand grains under the tires (the sandpaper effect). mg m -3 9 8 7 6 5 4 3 2 1 0 Traction sand Asphalt 1 2 3 4 5 6 7 8 9 10 11 12 13 Test Tests 1-2 without sand, 3-8 appr. 900 g m-2 sand, 9-14 appr. 1900 g m-2 sand Heikki Tervahattu 51 14 The sandpaper effect • The asphalt wear by tires is greatly increased by the sand between the asphalt and the tires. • This impact is not much effected by studs. Heikki Tervahattu 52 Emission levels affected by (2/4): - sand aggregate grain size - all fine-grained hard material on the streets enhances asphalt wear PM 10 vs grain size of traction sand 10 Grain size 2/5.6 mm Grain size 1/5.6 3 PM 10 [mg/m ] 12 8 6 4 2 0 Heikki Tervahattu Sand: 300 g/m2 53 Sand: 1000 g/m2 Sand: 2000 g/m2 Emission levels affected by (3/4): - Tire type: studded/friction tire - Statistically significant differences: higher concentrations with studded tires (Sign test, p=0.016): (Nokian tyres 175/70R13, studded: Hakkapeliitta 1; friction: Hakkapeliitta Q) Tire type vs PM 10 PM10 [mg/m 3] 3 Studded tire 2 Friction tire 1 0 Sand: 300 g/m2 Without sand Heikki Tervahattu 54 Sand: 1000 g/m2 Emission levels affected by (4/4): - Asphalt composition PM10 PM10-concentrations between two asphalts with Diabase as an anti-skid aggregate. Asphalt was made out of Mafic Volcanic Rock (2001-2002) and out of Granite (2003). μg/m 3 6000 From traction sand Studded tires 2000 From asphalt g/m 3 sand 5000 4000 Studded tires, 1000 g/m 3000 3 sand Friction tires, 1000 g/m 3 sand 2000 1000 0 A1 (2001) Heikki Tervahattu A1 (2002) A2 (2003) A1 (2001) 55 A1 (2002) A2 (2003) A1 (2001) A1 (2002) A2 (2003) Conclusions • Both tire studs and the use of traction sand increase PM emissions. • Sanding increases PM10-concentrations several fold independantly from the tire type. • The emission levels with traction sand are affected by the amount dispersed, by the grain size, and by the quality of the sand. • Sanding increased PM from asphalt: abrasive wear of the pavement by sand grains under the tires (the sandpaper effect). All hard material on road surface has a similar impact. • PM mass is mainly in coarse fraction, some contribution also to fine and submicron fractions • The results emphasize the interaction of tires, anti-skid aggregate, and asphalt pavement in the production of dust emissions. They all must be taken into account when measures to reduce road dust are considered. Heikki Tervahattu 56 • another ELPI is sampling background air in front of the van • data were preprocessed • time series of PM10 were plotted with the help of lognotes On-going developments of the sampling system • to be able to make stationary PM10 measurements for dispersion studies the combustion engine located on the roof of the vehicle (provides constant flow rate of 2000 lpm in the sampling tube) was changed to electric engine to avoid engine’s own emissions and a new sampling line through the roof of the van was built • validation of the sampling system • gravimetric mass measurements of the ELPI stages to estimate densities and further PM2.5 and PM1 Heikki Tervahattu 57 30.8.2006 Liisa Pirjola Heikki Tervahattu 58 18:22:40 18:10:10 W 18:23:32 17:57:40 17:45:10 F 18:12:20 Klaukkala 18:01:08 S 17:49:56 17:32:40 17:20:10 17:07:40 S 17:38:44 17:27:32 17:16:20 16:55:10 16:42:40 16:30:10 W 17:05:08 16:53:56 16:42:44 16:17:40 16:05:10 F 16:31:32 16:20:20 15:52:40 S 16:09:08 Espoo 15:57:56 15:40:10 S 15:46:44 14:39:40 14:27:10 W 15:35:32 14:36:04 14:14:40 14:02:10 13:49:40 F 14:24:52 14:13:40 Helsinki 2 14:02:28 13:37:10 13:24:40 13:12:10 12:59:40 S 13:51:16 13:40:04 13:28:52 13:17:40 15000 10000 5000 0 12:47:10 20000 S 13:06:28 12:55:16 25000 W 12:34:40 12:22:10 F 12:44:04 12:32:52 12:09:40 11:57:10 11:44:40 S 12:21:40 Helsinki 1 12:10:28 11:59:16 11:32:10 11:19:40 11:07:10 W S 11:48:04 11:36:52 11:25:40 F 11:14:28 10:54:40 10:42:10 S 11:03:16 10:52:04 10:29:40 PM10 (ug/m3) 30000 10:40:52 10:29:40 Speed (km/h) S = summer tire F = friction tire W = winter tire with spikes VIEME 20060503 S Time Röykkä Sniffer's speed 90 80 70 60 50 40 30 20 10 0 Tim e 30.8.2006 Liisa Pirjola Some expected results • Pavement wear and generation of inhalable particles from different low-noise and ”normal” asphalts • Comparison of summer, friction and studded tires in producing noise and dust • The properties of low-noise asphalts in winter maintenance and cleaning Heikki Tervahattu 59