Memo: Crumbling Sidewalks Not a Safety Hazard

Don’t expect Arlington’s crumbling sidewalks to be repaired any time soon.

That’s the message from a memo sent by the county’s Dept. of Environmental Services.

ARLnow.com first reported in March that many sidewalks built over the past two years were crumbling, most likely due to the combination of a snowy winter, salt and water-laden concrete.

While ugly, the sidewalks are not dangerous and are unlikely to crumble further, the memo says. While a possible repair method has been found, DES says it will not be widely applied until it can be tested during “a harsh winter.”

The memo, as obtained by ARLnow.com:

Dear Neighborhood Conservation Advisory Committee:

This is a follow-up notification to inform you about the status of sidewalk deterioration on recently constructed projects in the County. Since our last communication, we discovered the deterioration was not just isolated to a few locations that could quickly be repaired, but is in fact a region-wide problem. We want to keep you informed about what we have learned over the past few months and what our plan of action will be moving forward.

We conducted an extensive investigation including an independent analysis of deteriorated concrete samples, as well as a review of our specifications and construction practices. The investigation concluded that the concrete has a weak surface due to high water content and this weak surface can flake off when exposed to repeated freeze-thaw cycles in the presence of salt. This is known as scaling and is superficial in nature as it only affects approximately the top 1/8″ in most locations. This is also occurring in surrounding jurisdictions, including Fairfax and Montgomery County, who have similar specifications and construction practices.

Our investigation has also revealed that the strength of the concrete below approximately 1/8″ to 1/4″ is significantly higher and the scaling at most locations is not expected to get worse. Considering the overall depth of a sidewalk is 4″; the overall durability is also not likely to be affected.

We want to emphasize this is not a safety concern and only affects the appearance of the sidewalk. We have identified a possible repair methodology that may be viable for use at the most severely affected locations. This method will be evaluated at a few pilot sites before considering wider use.

The evaluation process will require the sites to go through a harsh winter to confirm efficacy. At that point, we will determine our next steps on repairs or continued monitoring for each affected location. Unfortunately, this will be a lengthy process and we ask for your patience.

As we continue to construct new sidewalks, the County is taking additional quality assurance measures to minimize the likelihood of more scaling, while still balancing costs against the risk of deterioration and its overall impact. The County has implemented new material testing protocols and has enhanced our construction inspection methods. We will also be proactively communicating with residents in areas where new concrete is installed about the importance of limiting salt use within the first year.

Arlington County will be working closely with other jurisdictions to compare repair methods and approaches and will continue to collaborate to find the best solution. We appreciate your understanding as we work to resolve this issue and we will continue to keep you informed.