Spray Applied Waterproofing System Allows Boston Tunnel to Open Ahead of Schedule

The 53-year-old Callahan Tunnel was closed shortly after Christmas 2013 for a multimillion dollar renovation project. The floor had badly deteriorated, and after a wall panel fell in 2012, many more were soon discovered to be defective. Because the main thruway to East Boston and Logan International Airport carries 30,000 cars a day, many drivers and area businesses were concerned a three-month closure would cause massive traffic problems and delays.

With the help of Bridge Preservation's state of the art, high performance tunnel waterproofing membranes, as well as their approved applicator Island Pavement Cutting Co., Inc.'s highly trained staff, the Callahan Tunnel project was completed two (2) days ahead of schedule with nearly one mile of new waterproofed suspended roadway and two miles of waterproofed curbs. The top four inches of the twelve-inch concrete roadway deck was removed using hydro demolition, and a new deck was then poured. After the new concrete was allowed to cure, Bridge Deck Membrane™ (BDM), the base high performance tunnel waterproofing was installed using two hi-tech spray robots, which allowed for a fast, consistent application of 80 mils, the thickness required to meet the ASTM C836 Crack Bridging Test. Immediately following the application of the base membrane, a 40 mil coat of aggregated BD Top Coat™ was applied. This slower setting topping membrane allows aggregate to be broadcast into it, which results in a highly durable non-skid coating that can accept temporary high speed vehicular traffic (<65 MPH), as well as providing additional shear resistance for the asphalt overlay, greatly enhancing the bond between these two layers. New curbs and gutters were also installed and coated with BD Aliphatic Coating, a highly durable, UV and color stable waterproofing coating system. Bridge Preservation LLC will be at the National Bridge Preservation Partnership Conference in Orlando, FL this April 21-25, 2014, (http://nbppc2014.org).  Bridge Preservation LLC will be doing live demonstrations where visitors can see the same products used on the Callahan Tunnel firsthand.