Title: Durability of Reinforced Concrete Elements and Structures Placed by Tremie in the Sea and with Slipforms by the Sea
Author(s): Jovo Beslac, Dubravka Bjegovic, and Marko Hranilovic
Publication: Symposium Paper
Appears on pages(s): 473-486
Keywords: concrete durability; corrosion resistance; marine atmospheres; mix proportioning; protective coatings; reinforced concrete; slipform construction; subsurface structures; tests; tremie concrete.
The paper discusses the results obtained by testing concrete quality and the degree of reinforcement protection in the piles of the submarine tunnel for the Coke Plant at Bakar, and in the walls of the water intake for the Rijeka Thermo-Power Plant, both placed by the tremie method. The shafts of the high chimney stacks of the Rijeka Thermo-Power Plant and the Bakar Coke Plant, erected by slip forms, were similarly investigated. The results obtained by tests and observations show that concrete for thin and highly-reinforced elements, to be placed by tremie, must be made with pure portland cement, or portland cement incorporating slag, having a low need of water for standard consistency, (measured according to Vicat), and with clean well-graded sand and coarse aggregate. Otherwise, mass concrete structures are preferred. Slipform erection of structures by the sea should be avoided, or, if used, the surface of the concrete should be protected additionally and completely (while slipform advancement is still under way) with cement mortar reinforced by the addition of polymer binders . This operation must be planned at the design stage and clearly specified.