Anchor bolts will mean very little if this construction mess in downtown Boston is the result of mixing contaminated dirt and fill into the composition of the concrete ceiling, walls or floor. Here is how the trick might have been done:

(1) While most eyes follow the light and focus on anchor bolts, our current investigation shows that there is a global demand for recycled construction products. This demand has increased substantially during the past two decades. The Big Dig produced over 4,000 miles and over 11 million cubic feet of dirt in the early digging stages. Most of this dirt and debris was processed for contamination and recycled into the Big Dig as clay landfill capping material, project backfill and as aggregate (mix) for the tons and tons of concrete needed for the project. The miles of extra dirt came from the demolition at the airport, the dredging of the harbor floor by the Super Scoop for the Ted Williams Tunnel, the digging of the coffer dam, excavation of miles underneath downtown Boston for the Tip O’Neil Tunnel, digging out tunnel entrances, etc.

In Big Dig II: Down Under, co-producer Arnie Reisman and I investigated this dirt and decided to follow the good news. The uncontaminated clay portions of this fill were going to be used to cap Spectacle Island and hundreds of Massachusetts landfills, an appropriate reuse of heavier clay materials. We were assured that there was a dirt-testing lab and that all of the contaminated soil was being properly distributed and reviewed by the Department of Environmental Protection (DEP). We were handed stacks of literature, interagency agreements regarding contaminated materials and many, many press releases about the massive volume of dirt being tested and processed. Occasionally there was other good news on the disposition of the dirt. There were mountains of dirt and any disposition was cause for celebration. After all, any unused dirt was going to cost the project and the managers big money for disposal. (2) Digging back through my Big Dig materials I unearthed a 1992 Memorandum of Understanding between the Department of Environmental Protection and the Massachusetts Highway Department about the “contaminated materials” in the soil. This addressed the process for oversight and inspections of the dirt for specific chemicals contaminating the soil that are harmful to humans and wildlife. Of course, those employees at the state DEP who were “overseeing“ the process with the Big Dig were salaried by the Massachusetts Highway Department and the Central Artery Tunnel Project. We won’t even begin to examine that closet. Why? Because right now we are trying to figure out the rabbit in the hat for Mitt’s Magic Show about the anchor bolts.

(3) During construction, there seemed to be an ongoing safety process regarding the concrete. Footage in Big Dig IV: Still Working contained a segment on the concrete testing process that was overseen by the Joint Venture of Bechtel and the Massachusetts Highway Department. This footage will soon be available at our web site, www.PolarisProduction.com where we will also uncover what we consider to be the design change that is causing continuous leaks in the I-93 tunnel.

This past winter, a small Big Dig contractor was accused and indicted for allegedly mixing too much old concrete in with new concrete to create a substandard mix that may be contributing to some leaks in the I-93 tunnel underneath Boston. This was a red flag that something may be NOT O.K. with at least some of the concrete but no one really noticed.

(4) By looking carefully at the Memorandum of Agreement it is obvious that the chemical contaminants in the DEP agreement are not the same chemical contaminants that can be harmful to the strength of the concrete or to the tendency of certain chemical contaminants to corrode embedded steel. When certain chemicals are present in the sand and soil used as the “aggregate” or the mixing soil that is added to cement to make concrete they can weaken or affect other properties of the concrete. These effects may happen over time and consequently may not be detected using temperature and slump tests on the not-yet-hardened concrete. The Joint Venture (the state and Bechtel) was required to sample portions of the concrete in all Big Dig contracts for strength. If the aggregate used to make this same concrete contained chemical contaminants that do not affect concrete strength, but can corrode steel fittings rapidly how would we know? Well, obviously we check the standards, right? That way we always mix in aggregate that does not contaminate the concrete in ways that can be disastrous.

When I looked for national standards on chemical contaminants and concrete mix, I found only an early attempt in Australia (1994-1996) to develop such construction standards for recycled material used in concrete construction. Many more Internet references attested to a lack of the type of precise testing over time that could lead to such standards. Perhaps the CA/T was following a set of engineering standards of which I am not aware. Of greatest concern is for the public to be informed about which chemical contaminates can affect the strength and durability of the concrete and which were present in what percentages in the recycled fill used throughout the CA/T tunnels. It is particularly important that an independent evaluation team makes a thorough investigation of the chemical properties of the recycled aggregate soil used throughout the project. This could help to identify areas that can be expected to have premature corrosion of steel rods embedded in concrete or that cause the concrete to expand or crumble or leak.

So 12 years of Republican controlled reassurances that the harmful soil was being disposed of properly failed to explain to us that the tests were only for the chemicals and soil properties directly dangerous to humans, for example, piles of dirt that contained mercury. The tests and press releases from the CA/T in 1991-1995 did not describe the concentrations of chemical contaminants in fill that could cause premature collapse of the tunnel ceiling or walls from faulty concrete. We are attempting to get those listed on our web site at http://www.polarisproduction.com/big-dig-concrete.html . We would appreciate hearing from any students, engineers or chemical engineers who can provide clarification on this matter. We will post your information and we will post any established standards for contaminates used in concrete aggregates along with any standards used by the CA/T in disposition of the dirt back into the Artery construction.