Title: Shotcrete Repairs 0f Concrete Structures in Marine Environment
Author(s): Joseph I. Heneghan
Publication: Symposium Paper
Appears on pages(s): 509-526
Keywords: accelerating agents; calcium aluminates; compressive strength; corrosion; deterioration; erosion; latex (plastic); marine atmospheres; mix proportioning; piers; protective coatings; . reinforced concrete; repairs; salt water; sea water; shotcrete.
This paper presents data, based on extensive rehabilitation of the underside of concrete pier in the harbor of Portland, Maine, of the compressive strengths of shotcrete used as the sole repair material. This paper reviews the principal causes of damage to concrete in a marine environment, including erosion by "scour action," alternate wetting and drying in the "splash zone" and the problems resulting from intrusion of the salts contained in sea water into the concrete. Recommendations as to proper proportioning and mix designs for shotcrete to be used as the repair material for such structures is presented as well as criteria for the use of accelerating admixtures in the shotcrete material. A discussion of the use of both latex modified and calcium aluminate cement shotcrete for rehabilitating deteriorated concrete in an aquatic environment is offered. This paper also considers the proper preparation of the surfaces to be repaired as well as the special problems associated with the placement of shotcrete while working in areas subjected to tidal and wave action.