Braintree, MA.

Cost-effectively extend pavement life

According to the American Society of Civil Engineers, 43% of roads in the United States are rated poor or mediocre. These rough roads cost the drivers approximately $596 in damages and accelerated vehicle depreciation every year. With this knowledge, why are so many communities waiting until their roads are in dire condition before treating them? One reason towns & cities wait to treat roads is they aren’t familiar with the process and benefits of the treatment. Pavement Preservation treatments on the top of the asphalt deterioration curve are cost-saving and will prolong the need for more expensive projects. In our ongoing effort to educate the Northeast on the benefits of pavement preservation, we took it upon ourselves to start an experiment using Fog Seal on the street outside our headquarters.


The Experiment

Beginning just a year after milling and repaving, we treated only one side of a two-lane road with a Fog Seal every three years. Our goal is to see how long this preventive maintenance treatment can prolong road life before a more serious and costly rehabilitation project is needed. We chose the southbound side of Granite Street to receive the Fog Seal treatments and the northbound side to act as the untreated control.


Treatment Chronology

September 2015
Southbound – Received a 1.5″ Mill & Pave
Northbound – Received a 1.5″ Mill & Pave

October 2016
Southbound – Fog Seal (0.10 gals./s.y.)
Northbound – NOT TREATED

August 2019
Southbound – Fog Seal (0.08 gals./s.y.)
Northbound – NOT TREATED

Next Treatment 2022
Southbound – Fog Seal
Northbound – NOT TREATED

We plan to continue this process until the need for more serious road restoration is needed.


The Treatment

The specific treatment we are using for the experiment is eFog, an asphalt emulsion product engineered by Ergon. eFog is a rejuvenating fog seal that can correct more severe distresses than a conventional fog seal alone. It can also extend the life of open-graded friction courses and worn chip seal surfaces by 2 to 4 years. eFog contains a polymer-modified asphalt base that provides a dense film thickness for increased durability and resistance to tracking. The rejuvenating component of the eFog emulsion restores essential elements in the existing asphalt, improving its overall quality and durability. Once it has cured, traffic can usually return to the pavement within 1-2 hours.

Process: Using a pressurized distributor, a light application of asphalt emulsion is sprayed directly onto the existing pavement. As it coats the entire surface, the emulsion works its way into cracks and surface voids to seal and protect the pavement.



Major Benefits


Fog Seals protect against moisture intrusion – After a light overnight snowstorm, note how the treated southbound lane (left) dried more quickly.




Fog Sealsprotect against oxidation & raveling – See the significant difference in macrotexture due to the raveling and loss of fines in the untreated NB lane (left).




Fog Seals delay the need for milling and repaving – After only 6 years, the untreated northbound lane is noticeably more distressed than the fog sealed lane.