Investigators in the US have advised the Boston Big Dig project owner to carry out tests on concrete used throughout the scheme fearing that it could be susceptible to alkali silica reaction (ASR), or concrete cancer.
The revelation is made in an engineering review of the entire Boston Central Artery project, ordered by the state government. The report, published last week, discovered an alarming catalogue of defects on the project.It calls for cracked and spalling concrete found in all of the project's seven tunnels to be further investigated by owners Massachusetts Turnpike Authority and the state government. Its authors fear traffic fumes and water ingress could trigger ASR.ASR occurs when silicates in concrete aggregate react with alkalis, for example, salts in sea water. The reaction creates an expanding gel that can cause rapid deterioration.The report was ordered by governor of Massachusetts Mitt Romney after the fatal collapse of reinforced concrete ceiling panels in the Big Dig Interstate 90 Connector Tunnel on 10 July (NCE
20 July). It was carried out by engineering firms Wiss, Janney, Elstner Associates, Schirmer Engineering and Environmental Systems Design.