Buchanan Dam, located on the Colorado River in Texas, is a critical infrastructure built in 1937 to form Lake Buchanan. The dam is one of the longest multiple-arch dams in the world and serves as a vital resource for hydropower generation and flood control. Over time, the dam developed high-pressure water leaks in its concrete arches, particularly in Arch 47. These leaks were exacerbated by seasonal temperature fluctuations, which caused thermal expansion and contraction, leading to recurring cracks and water infiltration. Restek, Inc., a contractor specializing in structural repairs, collaborated with Alchatek to implement a polyurethane grouting solution to address these issues.

Initial Assessment

An inspection of the dam revealed severe water infiltration concentrated in Arches 45-47. Arch 47 presented the most aggressive leaks, with water flowing under high pressure. Previous injection efforts had only provided temporary relief due to insufficient grout penetration and equipment limitations. The concrete structure’s thickness and seasonal movement posed additional challenges for effective leak sealing.

Proposed Solution

Alchatek recommended using a combination of advanced polyurethane products tailored to the dam’s specific conditions. Spetec PUR HighFoamer was selected for high-pressure leaks due to its rapid reaction time and expansive properties. Spetec PUR H100 and Spetec PUR F1000 were chosen for lower-flow areas requiring flexibility to accommodate joint movement. Higher-capacity airless pumps, such as the Titan 640 and Titan 8900, were utilized to ensure effective grout delivery.

Procedures

1. Preparation:

• To reach the midpoints of the concrete structure, deeper injection points were drilled using 24-inch and 36-inch masonry drill bits.
• Oakum rope saturated with grout was packed into joints to slow water flow during the injection.

2. Injection Process:

• Spetec PUR HighFoamer mixed with Alchatek Gen Cat was injected into high-flow leak areas using upgraded pumps capable of handling high pressure.
• Flexible grout mixtures (Spetec PUR H100/PUR F1000) were injected around rigid plugs to reinforce sealed areas and accommodate seasonal joint movement.

3. Post-Sealing Monitoring:

• The team monitored material expansion within cracks and adjusted injection pressure as necessary to ensure complete sealing.

Results

The grouting crew successfully sealed leaks throughout Arches 45-47. High-flow leaks in Arch 47 were effectively stopped using Spetec PUR HighFoamer, while lower-flow leaks were addressed with flexible polyurethane grout mixtures. Equipment upgrades allowed deeper injections, overcoming previous limitations and ensuring long-term durability against thermal stresses. Subsequent inspections confirmed substantial reductions in water infiltration, with no major leak recurrence reported.

Conclusion

The Buchanan Dam leak-sealing project demonstrated the importance of combining advanced materials with appropriate equipment upgrades to address complex infrastructure challenges. Restek, Inc.'s collaboration with Alchatek resulted in a sustainable repair strategy that restored the dam’s structural integrity while accommodating environmental factors such as temperature fluctuations. This case underscores polyurethane grouting’s effectiveness as a solution for high-pressure leak repair in large-scale concrete structures.

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