Evaluating Methods to Seal Leaking Contraction Joints in Dams

Project ID: 7688
Principal Investigator: David Starbuck
Research Topic: Repair and Maintenance
Funded Fiscal Years: 2015 and 2016
Keywords: None

Research Question

What are effective methods to seal leaking contraction joints in dams without affecting the stability of the structure?

A scoping study was performed in 2014 and a promising method using small hydrophilic polyurethane chips was used. This method was tested at Grand Coulee Dam in Washington with good initial results.

This proposal is going to research the hydrophilic chips method further. It will look to improve the compositions of the chips, the delivery method and other factors.

Need and Benefit

All concrete dams have joints, cracks, and seams which can develop leaks. Contraction joints in concrete dams have waterstops to prevent water leaking from the reservoir into the joint. Over time, the waterstops can begin to leak.

These leaks can be quite large and cause many problems within the dam and can lead to millions of dollars of increased maintenance costs across numerous facilities, since they corrode metalwork, increase operating costs through increased pumping to remove excess water, reduce worker productivity as they work around the leaks, etc.

Contributing Partners

Contact the Principal Investigator for information about partners.

Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Evaluating Methods to Seal Leaking Contraction Joints in Dams (final, PDF, 6.9MB)
By David Starbuck
Publication completed on September 30, 2016

All Reclamation concrete dams have joints which experience pressure caused by the reservoir water elevation. These joints have waterstops to prevent water leakage through the joint. Over time, the waterstops can begin to leak. These leaks can lead to millions of dollars of increased maintenance costs across numerous facilities. Conventional leaking contraction joint repair methods are either very expensive or do not last long. We developed an inexpensive method to deliver repair materials deep under water (Travel Report 2013). To test those methods, we built a laboratory fixture to simulate a leaking contraction joint in a dam under pressure. With this fixture we tested different repair options. These options included sawdust, hydrophilic waterstop chips, chemical grouts used for sealing water leakage through concrete, and combinations of the chips and grouts. In this testing we found that sawdust didn't slow the water flowing through the test fixture joint. Hydrophilic chips slowed the water by as much as 65%, and Hydrophilic chips combined with some chemical grouts completely stopped the water flow through the test fixture joint. These methods can be implemented to significantly reduce or completely stop the infiltration of water and are much cheaper than many alternatives.

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Last Updated: 6/22/20