Cutback asphalt and emulsified asphalt

What are cutback asphalt and emulsified asphalt?

Cutback asphalt and emulsified asphalt are used for a number of applications during road construction. In preparing these products, asphalt cement is mixed with either a petroleum diluent to produce cutback asphalt or with emulsifiers, water, and sometimes petroleum diluent to produce emulsified asphalt. Once the liquefied asphalt cement is applied during road construction, the diluent petroleum solvent (in the case of asphalt cutbacks) and water (in the case of asphalt emulsions) evaporates leaving the cured residual asphalt cement. The application of asphalt causes emissions of volatile organic compounds (VOC) through the evaporation process described above and contributes to the creation of ground-level ozone and particulate matter, which are major components of smog.

The majority of asphalt used in Canada is the emulsified asphalt type. Based on a study conducted for Environment and Climate Change Canada in 2010, 301 kilotonnes (kt) of liquefied asphalt were used in Canada in 2009, 85 percent of which was emulsified asphalt while 15 percent was cutback asphalt. For that year, the total VOC emissions associated with this usage were estimated to be 8.8 kt (5.2 kt for cutback asphalt and 3.6 kt for emulsified asphalt). While cutback asphalt represented only 15 per cent of asphalt use in Canada in 2009, it was responsible for 59 per cent of the VOC emissions associated with the use of asphalt. The same study estimated that VOC emissions from asphalt could reach 10.8 kt in 2020 without an environmental framework to guide the use of asphalt in Canada.

Code of practice

On February 25, 2017, a Notice of the issuance and publication of the Final Code of Practice for the Reduction of Volatile Organic Compound (VOC) Emissions from Cutback and Emulsified Asphalt was published in the Canada Gazette, Part I.

The main objective of this Code of Practice (the Code) is to protect the environment and the health of Canadians while maintaining road safety by recommending best practices that encourage the use of low VOC emitting asphalt. The Code seeks to fulfil this objective by providing guidance to the manufacturers, importers, sellers and users of asphalt. In particular, it recommends ways to help reduce VOC emissions from the use of cutback asphalt and emulsified asphalt.

The Code includes a request for report submissions by asphalt manufacturers. The first report should be submitted by March 31st, 2018 and should cover activities from the 2017 calendar year. Subsequent reports should be sent every two years by March 31 of those years and should cover activities relevant to the previous calendar year.

To assist with reporting, you can consult:

Discussion paper and proposed code

A consultation session on possible control measures to establish VOC concentration limits from asphalt products was held in March 2012. A discussion document that outlines the background information and discusses potential approaches was developed.

After the March 2012 consultation regarding the discussion paper, a Code of Practice was deemed as an efficient and cost-effective tool to achieve up to 5 000 tonnes of VOC reductions annually while minimizing the burden on the road construction industry.

On April 4, 2014, Environment and Climate Change Canada published a draft code of practice for a 60-day comment period.

Based on comments received on the April 2014 draft code, a notice for the proposed code was published in the Canada Gazette, Part I on March 5, 2016. Stakeholders are invited to comment on this proposed code during a public consultation period ended on May 4, 2016. Comments received during this consultation period were considered in finalizing the code. A summary of these comments are available on-line.

Contact information

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Questions and inquiries can be directed to Environment and Climate Change Canada – Product Division at:

Telephone: 888-391-3426 or 819-938-4483
Fax: 888-391-3695 or 819-938-4480

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