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Early DC Metro Concrete Tests Favorable

Wednesday, July 25, 2018

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Initial testing triggered by a whistleblower lawsuit, which called out faulty concrete panels on Washington D.C.’s Silver Line Metro stations, suggests that the problem may not be as widespread as once feared.

The lawsuit pointed out that the use of incorrect stone, along wtih improperly mixed concrete, could lead to the breakdown of concrete panels at Silver Line stations slated to open in 2020. In the initial testing, the Metropolitan Washington Airports Authority took core samples from 20 of the panels.

Whistleblower Lawsuit

In May it was revealed that issues with the panels discovered along the $2.7 billion Silver Line Metro extension in Northern Virginia were apparently known in 2016, according to the timing of the whistleblower lawsuit.

More than a year before the Metropolitan Washington Airports Authority and contractor Capital Rail Constructors were made aware of the issue with the panels, Nathan Davidheiser, who worked for subcontractor Universal Concrete Products, filed the whistleblower lawsuit. Universal Concrete Products produced the faulty panels; Davidheiser alleged he was instructed by his employer to lie about quality-control tests during their fabrication.

According to WTOP, both the Airports Authority and CRC noted that they recognized flaws in the concrete panels in the beginning of 2017. As a result, the FBI and U.S. Department of Transportation Inspector General conducted an investigation, as federal money was spent on the second phase of the project.

Earlier this month, the state of Virginia, along with the federal government, joined Davidheiser's suit against Universal Concrete Products for allegedly knowingly providing precast concrete panels that did not meet contract specifications, along with cutting corners regarding quality-control requirements and falsifying records related to panel quality.

Recent Findings

The first half of the test samples taken have not revealed any significant issues, noted Charles Stark, MWAA vice president for the Dulles Corridor Metrorail Project. 

Two labs—one for the Airports Authority and another for the contractor building the rail line—are taking a look at the sample results. So far there has been no evidence of microcracking or a reaction taking place, according to Stark. If a reaction were to occur, it would be fueled by water getting into the panels; to prevent this, and in response to the improper concrete mixture, the contractor will be providing protective silane coatings every 10 years.

“We’re fairly certain that, unless we see something untoward in the remaining laboratory examinations, keeping water out of the concrete will preclude any problem going forward,” Stark said.

Test results will likely be released in the next three weeks, with Metro reviewing the results and testing separately. The panels must also undergo certain material certifications.

Test trains could be running on part of the tracks as early as October.

   

Tagged categories: concrete; Contractors; Government; Infrastructure; Testing + Evaluation

Comment from Tom Schwerdt, (7/25/2018, 8:08 AM)

Presumably they are talking about using reactive aggregates, which increase alkali-silica reaction (ASR) - reducing moisture is a great method to slow this down. However, aren't these panels holding back (moist) soil? If so, simply putting silane on the front wouldn't stop the main source of moisture intrusion. ASR also takes time - perhaps these panels will be fine for 20 years rather than the 50+ they should have been designed for. Secondly, the other accusation was an overly high water:cement ratio, which means that they should be doing strength tests on the cores.


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