Title: Durability of Concrete Containing Supplementary Cementing Materials in Marine Environment

Author(s): V. M. Malhotra, G. G. Carette, and T. W. Bremner

Publication: Symposium Paper

Volume: 100

Issue:

Appears on pages(s): 1227-1258

Keywords: blast furnace slag; compressive strength; concrete durability; fly ash; freeze-thaw durability; long-time study; marine atmospheres; portland cements research; seawater; silica; wetting and drying tests; Materials Research

DOI: 10.14359/2094

Date: 4/1/1987

Abstract:
Evaluation in marine environment of normal and lightweight concretes incorporating supplementary cementing materials is discussed. A series of 138 concrete prisms, 305 x 305 x 915 mm in size, were cast over a five-year period starting in 1978, for long-term exposure at Treat Island, Maine. The prisms were positioned at mid-tide level on a rack at the entrance to the Bay of Fundy, and this represents what is perhaps the most severe marine exposure conditions for concrete. The test specimens are exposed to repeated cycles of wetting and drying and to an average of about 100 cycles of freezing and thawing per year. The test specimens are monitored at yearly intervals: the specimens are photographed and rated on a visual basis. Ultrasonic pulse velocity is also determined. After up to 8 years of exposure, both normal-weight and lightweight air-entrained concretes show no degradation of the mass of the concrete; however, some of the specimens show significant surface deterioration. The amount of deterioration generally increases with an increasing water-to-cementitious materials ratio, and increasing replacement of cement with slag and fly ash. It appears that surface deterioration can be avoided if the cement content is kept to at least a certain minimum level. The tests confirm that over long exposure duration, non-air-entrained concrete is not durable in this environment.