Use of Aqualastic to encapsulate degraded RCC Lining in Canals
Can Aqualastic provide a cost effective way to encapsulate degraded sections of Roller Compacted Concrete (RCC) and Shotcrete to seal degraded portions of the canal lining to stop further degradation, erosion, and to reduce or eliminate seepage?
Aqualastic is a polyurea elastomeric coating that is sprayed onto a prepared surface. This product is similar to spray on bedliners commonly used in pickup trucks. Aqualastic is currently applied to concrete canal lining as a crack sealer. We are proposing to apply Aqualastic over a section of canal approximately 75 feet long by 36 feet wide to measure its ability to achieve seepage reductions and its ability to protect degraded or eroded sections of the lining. The tests will also determine how well the product will adhere to the RCC and shotcrete substrate over time over a large area. As a secondary benefit, we believe the product will also result in increase transmission efficiency as a result of reducing the channel roughness due to a smoother surface area.
The current method of repairing the RCC and shotcrete lined canal is to patch the deteriorated section with more concrete. This patch is 3 to 4 inches thick and over time will reduce the available canal cross section for water transmission. This process is also labor intensive and costly.
The North Unit Irrigation District is interested in finding a material that is economical, will result in a smooth surface, is relatively easy to apply, will not reduce channel capacity, and will last for many irrigation seasons.
Need and Benefit
Reclamation has many concrete and shotcrete lined canals that are in various stages of repair. Reclamation needs to find cost effective ways to repair and maintain these canals. The standard way to repair concrete lined canals is to patch with more concrete. For a shotcrete application the thickness of the repair varies between 2 to 4 inches that is placed over the existing shotcrete. This method reduces channel capacity and may add to channel roughness which will also reduce channel capacity. In order to not reduce the channel capacity the old shotcrete and/or concrete would need to be removed which would increase the cost of the repair.
Aqualastic has the potential to be a cost effective repair method that does not reduce channel capacity. It also has the potential to reduce seepage.
Reclamation and Irrigation Districts have many miles of concrete and shotcrete lined canals across the American West. This technology should be easily transferrable to other irrigation districts and Reclamation offices.
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.
Use of Aqualastic to encapsulate degraded RCC Lining in Canals (final, PDF,
By Kathy Kihara
Publication completed on September 30, 2015