British Columbia finds success with warm mix

Apr 06, 2017

The fall of 2016 was a big achievement for warm mix in British Columbia. After previous struggles with warm mix asphalt (WMA), the B.C. Ministry of Transportation approved Evotherm® P25 as their first additive used for the purposes of both a liquid antistrip (LAS) and WMA.

“The Ministry had experienced many issues with warm mix and liquid antistrip products in the past and was skeptical of using it again,” explains Chuck Van Dyk, director of bitumen marketing at Colasphalt. “Ingevity’s Evotherm has been successfully used in other parts of Canada, so we wanted the Ministry to evaluate its performance on a pilot project in Nelson. They looked at plant production, asphalt placement, in-place density and mix volumetrics.”

Colas-owned Selkirk Paving contracted the job and Colasphalt supplied the liquid asphalt cement (bitumen) on the pilot project. Brenntag supplied the P25 used in the liquid asphalt. Production and paving went well and proved that Evotherm could be used to effectively lay asphalt at 248 F (125 C).

“We produced 1800 tons of a PG 58–28 liquid asphalt with Evotherm,” explains Lisa Mattern, asphalt additives manager at Brenntag in Canada. “The mix contained 25 percent RAP and had a total asphalt content of 5.8 percent. We dosed Evotherm to 0.4 percent of the total asphalt.”

Evotherm P25 is now approved for use as both a LAS and WMA additive throughout B.C., Canada. The country as a whole is also recognizing additional cold weather paving and long haul value from the P25 additive.

“Canada is looking for cost effective ways to reduce emissions and greenhouse gasses while paving with asphalt,” explains Todd Strynadka, technical services manager with Terus Construction. “In fact, future federal funding for Canadian construction projects will be contingent upon these reductions being met. Warm mix is a great solution as long as the additive allows you to significantly reduce production temperatures and still put down quality asphalt. Evotherm really shined on this project.”

“The crew and the Ministry seemed most impressed with the reduction in smoke coming off the mix during production and laydown,” explains Bob Siffert, technical marketing manager at Ingevity. “This is an exciting project because P25 is the Ministry’s first dual purpose LAS and warm mix additive. And we also proved we can improve density, haul mixes further, pave in cooler temperatures and reduce fuel consumption. We hit about seven birds with one Evotherm stone on this project!”