freezing of salty solutions vs mobile surface condition ...€¦ · connector or cigarette lighter...

TECONER OY Technical Consulting & Research

Freezing of Salty Solutions vs Mobile Surface Condition and

Friction Measurements

PIARC TC 2.4 Workshop, 11.03.2015 Helsinki

Taisto Haavasoja

[email protected]


Contents • Freezing process

– Composite mixture of clean ice and anti-icer solution

– Consequences to winter maintenance

• Mobile measurement of winter surface conditions – RCM411 Road Condition Monitor – Mapping of winter road conditions

• Future applications – Global service of slippery surface

conditions – Real time control of gritting based

on measured conditions

11.03.2015 PIARC TC 2.4 Mobile Road Surface Condition Measurements 2


Phase Diagram of NaCl


Ice Fraction = b / (a+b) Brine Fraction = a / (a+b)


Research on Freezing Solutions

T. Haavasoja, J. Nylander and P. Nylander, “Relation of Road Surface Friction and Salt Concentration”, SIRWEC 2012, Helsinki

• Low salt concentrations are adequate

• Pressure dependence

A. Klein-Paste, J. Wåhlin, “Wet pavement anti-icing — A physical mechanism”, Cold Regions Science and Technology 96 (2013), pages 1–7

• Minimum Brine Fraction is independent of anti-icer chemical



Salt Concentration and Slipperiness



Minimum Brine Fraction vs Pressure



Consequences to Winter Maintenance

• Fairly low salt concentrations keep friction at tolerable levels, even at low temperatures

0.1 mm * 1 % = 1 g/m² NaCl

• Let surface partially freeze -> reduce liquid spray

• Liquid anti-icers work well

• Potential for saving salt and anti-icers

– measure friction and water layer -> adjust required salt amount

– Mobile Winter Road Condition Monitoring



Road Condition Monitor RCM411

• measurements

– road surface condition • dry, • moist, • wet, • icy, • snowy, • slushy

– water layer thickness

– modeled friction

– surface temperature



Road Condition Monitor RCM411

• user interface

– cell phones • BlueTooth link to cell phone

• power from the trailer connector or cigarette lighter

– data communicated to selected servers

– results on a map interface as color coded lines

– Mobile Road Condition Map


http://keliapu.net/map


µTEC Friction Meter

• µTEC

– cell phone application

– accelerometer based absolute friction meter

• used for friction reference

– development of RCM411 friction model



Map Interface for Friction …



Surface state…



… Water Layer



… Surface Temperature



Water layer, Hki-Vantaa Airport 29.12.2011



Research Publications, tests …

RCM411: • FTA 2011, test report of the Finnish Transport Agency

• FTA 2013, test report of the Finnish Transport Agengy

• SIRWEC 2012 Extended Abstract ”Experiences of Mobile Road Condition Monitoring”

• SIRWEC 2012 Presentation ”Experiencies of Mobile Road Condition Monitoring”

• PIARC 2014 Article ”Continuous Skid Resistance Test”

• PIARC 2014 Presentation ”Continuous Skid Resistance Test” – standard deviation in friction is on the order of 0.10

Freezing of Salty Solution and Friction: • SIRWEC 2012 Extended Abstract ”Relation of Road Surface Friction and Salt Concentration”

• SIRWEC 2012 Presentation ”Relation of Road Surface Friction and Salt Concentration”

• Look also at A. Klein-Paste, J. Wåhlin (NTNU Trondheim), “Wet pavement anti-icing — A physical mechanism”, Cold Regions Science and Technology 96 (2013), pages 1–7

• AASHTO/TRB SCOM 2015 ”Freezing of Anti-Icing Solutions on Road Surfaces”


http://www.teconer.fi/Friction_Meters_2011.pdf

http://www.teconer.fi/Friction_Meters_2011.pdf

http://www.teconer.fi/lts_2013-52_comparison_study_web.pdf

http://www.teconer.fi/lts_2013-52_comparison_study_web.pdf

http://www.teconer.fi/SIRWEC_2012_Experiences of Mobile RCM_ID14.pdf




http://www.teconer.fi/ID14 Haavasoja - Mobile Road Condition Monitoring.pdf




http://www.teconer.fi/IP13-Haavasoja-E.pdf







http://www.teconer.fi/Presentation13.pdf







http://www.teconer.fi/SIRWEC_2012_Friction and Salt Concentration_ID17.pdf







http://www.teconer.fi/ID17 Haavasoja - Relation of Road Surface Friction and Concentration.pdf








Friction Test Run 11.3.2012 Road Laboratory of Aalto University

11.03.2015 PIARC TC 2.4 Mobile Road Surface Condition

Measurements 18

http://www.gpsvisualizer.com/map_input?bg_opacity=90&colorize_gray=0&colorize_max=0.7&colorize_min=0.2&form=google&google_wpt_filter_sort=0&hue2=120&legend_steps=6&lightness=100&trk_colorize=custom&trk_colorize_custom=friction&trk_opacity=100&trk_width=8&form:remote_data=http://keliapu.net/Destia/RCMapD01_12_03_11_18.csv

http://www.gpsvisualizer.com/map_input?bg_opacity=90&colorize_gray=0&colorize_max=0.7&colorize_min=0.2&form=google&google_wpt_filter_sort=0&hue2=120&legend_steps=6&lightness=100&trk_colorize=custom&trk_colorize_custom=friction&trk_opacity=100&trk_width=8&form:remote_data=http://keliapu.net/Destia/RCMapD01_12_03_11_19_33.csv


Aalto University Friction Test

11.03.2015 PIARC TC 2.4 Mobile Road Surface Condition

Measurements 19


FIRWE Project (2011-2014)

• TEKES project

• RCM411 testing started with Itella logistics vehicle in Helsinki – driving on working days in

the morning and in the afternoon

– moved to a taxi in Helsinki region

• Ravensburg, Germany – Buses!

• Finnish Transport Agency



New fixing parts for RCM411



Summary …

• Mobile Road Condition Monitor RCM411

– surface state, water layer, friction and surface temperature (RTS411)

• standard deviation is on the order of 0.10

– various user interfaces available

• cell phone, tablet or PC

• real time map interface

• Mobile Road Condition Map


http://keliapu.net/map


Summary … • RCM applications

– a tool for winter maintenance

– a tool for quality control

– a tool for learning and training

– friction mapping

– thermal mapping

– information to drivers

– warning for aquaplaning, …


http://www.teconer.fi/index_tiedostot/Page1037.htm


Future Vision • Global service of slippery surface conditions

• Real time view of slippery conditions on a world map

• Control of gritting based on measured conditions • From rules of thump to calculated amounts based on measurements

and weather forecasts to keep brine fraction on safe side


freezing of salty solutions vs mobile surface condition ...€¦ · connector or cigarette lighter...

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