Materials, Methods & Technologies, Volume 16, 2022

Abstract: The forthcoming repair works on the pier wall of the port of Bourgas envisage the construction of a combined structural and protective barrier against the ongoing processes of suffusion from the quay wall to the sea. On the water side of the quay, the construction of a pilot system with two types of poured concrete piles with different diameters for barrier counteraction against suffusion is envisaged. The forming wavy vertical protective wall is at a distance from the existing quay wall, built of concrete blocks with relatively displaced geometry, which does not provide a smooth vertical surface for direct contact with the pilot system. In this regard, the need to design a technological option for dense filling of the volume between the existing concrete blocks and the pilot system designed for construction is in favor of the effective solution of the complex technical task. The report proposes an innovative technical solution based on the specific characteristics of specially designed sulphate-resistant hybrid fiber-reinforced concrete for underwater concreting with high strength-deformation characteristics, resistant to the aggressive effects of operation in seawater. The developed working concrete mix design includes special corrosion-resistant steel fibers and special chemical admixtures – high range water reducing admixture (HRWRA), internal crystallization chemical one and anti-washout admixture (covering the specific requirements of the US Army Corps of Engineers - CRD - C661-06 Specification for Anti-Washout Admixtures). The obtained main strength-deformation indicators of the proposed composition of the special concrete are discussed, which confirms the possibility of satisfying all technological requirements for the project.