Transport Scotland – Bear Scotland – Innovative Global Products Results following the trial of ECO-THAW as a de-icer Aberdeenshire January 2011
ECO-THAW is a viscous liquid which acts as a freezing point depressant, that can be used in various forms for the purpose of anti-icing and de-icing as and when the prevailing conditions dictate.
It is derived from blending, by-products of the distillation and fermentation process with Magnesium Chloride to suit the demands of its end user.
Traditionally in the UK it has been used as an additive and coating to rock salt, whereby it is spread using the traditional gritting process. However in many other places around the world the liquid is used as a wetting agent in pre-wetting, as an enhancer to brine spraying (extending the usability to lower working temperatures); or by spraying alone as an anti-icer or de-icer.
The trials that were undertaken in Scotland (Jan 2011) with ECO-THAW set out to prove its use as a de-icer in cold temperatures. The road that was chosen that had around 50mm of solidly compacted snow and ice, which had been untouched (by way of ploughing and salting) for some 6 weeks. RST on the day was -8C.
ECO-THAW (ET-S) was sprayed onto the surface using straight line dribble jets at low pressure using a converted weed spraying rig on a Fast-Track tractor as shown in the image below.
The result that followed showed the material starting to work with immediate effect, and followed with the dribble lines widening and cutting down into the hard pack leaving furrows at 30mins.
After 50mins it can be seen in the images below that the liquid lines have started to merge together and de-bonded the hard pack from the road surface allowing it to be scraped clean.
ECO-THAW after 5mins
ECO-THAW after 30mins
Complete de-bond at 50mins
Start of trial area at 50mins
Foot scrape after 50mins
The second phase of the trial (and the point at which we are reporting from) was to establish the science behind the success, which in turn could further help inform on appropriate spread rates, its usage as an enhancing agent to brine and the development of economical blends to aid the dilemma of severe winter weather working be it as an anti-icer or de-icer.
Analysis was carried out by The Department of Chemistry at Durham University under the direction of Dr. Jonathan Sellars, using differential scanning calorimetry (DSC) to accurately determine the freezing point of the various samples provided and blended in the laboratory.
Initial testing by IGP took neat samples of the 3 ECO-THAW mixes and analysed their re-spective freezing points through a series of dilutions in rainwater. (ET-C, ET-L, ET-S)
For comparison purposes the results are plotted against the well established profile of 23% saturated salt brine mix. (Graph A)
Phase two of the testing took the 3 samples of ECO-THAW and blended them with a 23% brine sample as provided by Amey from their Tanchoside depot.(fp determined as -22.96C). The blending followed a profile that had already been established through work in North America 30/70, 50/50, 60/40. – % by volume of ECO-THAW mix with saturated brine. The results of their respective freezing points are represented in graph B (and A)
We then took two of the brine blends which seemed to provide economical mixes (ETS-30 and ETL-50) and further analysed them through the dilution programme with rainwater with the results reported in Graph C.
Graph A Results of Freezing Point Determination using Differential Scanning Calorimetry for ECO-THAW blends and their subsequent dilution in Rainwater compared to 23% Brine and Enhanced Brine Solutions with ECO-THAW
Graph B Results of Freezing Point Determination using Differential Scanning Calorimetry for ECO-THAW Enhanced Brine solutions compared to 23% saturated Brine diluted
Graph C Results of Freezing Point Determination using Differential Scanning Calorimetry for ECO-THAW Enhanced Brine solutions diluted in Rainwater compared to 23% saturated Brine diluted.
ECO-THAW Enhanced Brine solutions diluted in Rainwater compared to 23% saturated Brine diluted. Test results following the analysis of ECO-THAW samples using Differential Scanning Calorimetry to accurately determine the freezing point of the liquids
All results are in ‘minus’ Centigrade and dilutions % by volume.