CHANTILLY, Va. (AP) — Concrete panels installed in the $2.6 billion project extending the D.C. region’s Metrorail Silver Line to Dulles International Airport are not as durable as they should be.
Thousands of areas along the extension will need to be dealt with. And some of the concrete will need to be completely thrown out, despite being already installed.
Charles Stark, director of the Silver Line project, said the concrete is supposed to last 100 years but was not mixed properly by a subcontractor.
To fix the problem, the concrete will have to be periodically coated with a special substance to enhance its durability.
Stark said the additional costs will be borne by the contractor and will not delay the anticipated 2020 opening of the Silver Line’s second phase.
Every station except the Dulles Airport station is affected.
According to NBC Washington, the water-to-cement ratio is off, there isn’t enough concrete covering the steel underneath and safeguards for water to expand and contract are lacking.
Stark said another 60 panels are being replaced because the reinforcing steel mesh is positioned in a way that it could too easily rust.
The contractor on the project did not specify how much the fixes would cost.
The issue was first reported by WRC-TV.