From: Massachusetts Institute of Technology
Published September 14, 2017 02:40 PM

Investigating a big dam concrete problem

When the Mactaquac Dam opened in New Brunswick, Canada, in 1968, it was expected to have a service life of 100 years, but a chemical reaction occurring within the concrete used to build the dam has drastically shortened that timeline.

“Concrete is a mix of cement, crushed rock, sand, and water. Alkali-silica reaction, the cause of the major issues in New Brunswick, occurs when alkalis in the cement pore solution encounter reactive forms of silica in the rock used to make the concrete,” explains Jeremy Gregory, executive director of the MIT Concrete Sustainability Hub (CSHub). “The reaction produces a gel which expands as it absorbs water and exerts pressure that can cause cracking and result in structural problems in concrete infrastructure.”

Researchers from the CSHub, the University of New Brunswick (UNB) and Oregon State University (OSU) have teamed up on a project to address several concrete durability issues, including alkali-silica reaction (ASR). Researchers at UNB are conducting ASR experiments, while OSU researchers are leading work on another durability issue known as freeze-thaw. Most of the project’s computational work is done at MIT, along with some experimental measurements.

Read more at Massachusetts Institute of Technology (MIT)

Photo: Researchers from the MIT Concrete Sustainability Hub, the University of New Brunswick, and Oregon State University visited the Mactaquac Dam in New Brunswick, Canada, in August.

Credit: Jeremy Gregory / MIT Concrete Sustainability Hub

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