Comparative Study of the Mechanical Properties and Performance, Under Accelerated Aging, of Four Repair Systems for Concrete Hydraulic Structures

摘要

The performance of conventional, polymer-modified, steel-fiber, epoxy, and silica-fume mortars subjected to a high velocity water flow is described. Besides the mechanical requirements and wearing resistance of concrete hydraulic structures, especially spillway surfaces, the high solar radiation and the environmental temperature contribute significantly to decreasing in the lifespan of repairs. Such contributions are particularly evident on surfaces repaired with polymer-modified concrete and epoxy mortar, mainly at the interfaces between the substrate and the environment. This paper presents the results of a comparative study to determine mechanical properties, adherence, and accelerated aging of four repair systems. Two systems exhibited higher performance: the epoxy and silica-fume mortar. Steel-fibers, due to good adherence to the substrate and good mechanical performance, are appropriate for use as an intermediate layer for underwater repair. This system exhibited an apparent corrosion at the steel-fibers on the surface after aging and underwater abrasion tests, which should be considered prior to being used on exposed spillway slab surfaces.