Repair, Evaluation, Maintenance, and Rehabilitation Research Program. State-of-the-Art Procedures for Sealing Coastal Structures with Grouts and Concretes

Many Corps rubble-mound breakwaters and jetties have become permeable to wave transmission and sand transport, conditions which result in increased Operation and Maintenance dredging costs, delays to navigation, and damages to recreational craft and marina facilities. A cost-effective alternative to traditional methods of rubble-structure rehabilitation (dismantling to rebuild core sections, chinking layers along surfaces, additional armoring layers, etc.) has been determined to be drilled and grouting (sealing) a vertical barrier curtain along the center line of the structure from the bottom to approximately mean higher high water. Sealing of permeable structures (almost exclusively rubble-mound) by filling significantly large voids is a concept not routinely considered by coastal engineers. However, the basic underlying technology necessary for closing such large voids and for stabilizing sand within a structure has been developed previously in the grouting field for sealing cracks and fissures in rocks or dam foundations. Adaptation of this technology and promotion of the use of cementatious, chemical, and asphaltic products in coastal structures to reduce wave penetration and sand infiltration were initiated by WES in 1986, although specific guidance does not presently exist for sealing breakwaters and jetties by those means. Rehabilitation (REMR) research Program Work Unit NO. 32375, 'Rehabilitation of Permeable Breakwaters and Jetties by Void Sealing,' will develop and convey state-of-the-art knowledge in this area to appropriate Corps and other personnel charged with field application responsibility for performing such sealing measures.