Deterioration and Repair of Concrete in the Lower Monumental Navigation Lock Wall.
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS STRUCTURES LAB
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Deterioration of navigation lock wall concrete due to freezing and thawing is a serious problem which is usually attributed to the ineffectiveness or lack of a proper air-void system in the concrete. Most of the affected locks were constructed many years ago before air-entrained concrete began to be widely used. However, Lower Monumental Lock, one of the largest locks in the world, has only been in service for 10 years yet has serious surface deterioration. Depending on the extent of concrete deterioration, conventional techniques for repair of deteriorated concrete surfaces normally require the removal of about 1 ft of face concrete, placing anchors and reinforcing steel mat, and replacing the removed concrete with new high-quality air-entrained concrete. This type of repair is very expensive and can put a lock out of service for a long period of time. At lower Monumental, the cost of conventional repair was estimated to be prohibitive, and the lock could not be taken out of service for more than a matter of weeks. A coating was needed that a could be applied in a short period of time, b might prevent continued damage from freezing and thawing, and c would be permanent under the adverse service conditions. Six coatings of various portland cement and fine aggregate mixtures were pneumatically applied to a section of the lock wall for evaluation. Each was applied at a thickness of approximately 38 in. A conventional dry-mix shotcrete was used as the control material and was compared to fiberglass fiber reinforced mortar applied by the spray-up process with and without latex.
- Ceramics, Refractories and Glass
- Coatings, Colorants and Finishes
- Civil Engineering