Dispersible Underwater Concrete Engineering Applications

Upon the placing of underground concrete members by plain concrete, segregation which may result in the coming out of water and reduced strength are easily to occur, which will present great difficulties for construction and cause high construction cost and long construction period. To overcome the fore-mentioned shortcomings of plain concrete, the research of underwater concrete had started in 19r )s in foreign countries. It has been proved by application to projects and practices that the underwater concrete sure has certain advantages over the plain one. However, it has just overcome some shortcomings of the plain concrete instead of all its shortcomings, which is still far from the expected results.This paper presents the undispersed underwater concrete formulated by the adding of flocculant (UWB, SCR), a sort of admixture, whose mixing has involved the technology of materials, construction technology, special plants and engineering structures. The key part of this technology lies in the adding of flocculant, a special admixtures, into the mix of concrete. As a kind of new construction materials, the so-prepared concrete mix is undispersed and unsegregated in water and is characterised by no flow loss, leveling by self-flow and self compacting.The underwater concrete has already found an extensive application in many key projects of Shengli Oiflield, Jilin Oilfield, Liaohe Oilfield, Pipeline Bureau of East China, Bohai Petroleum Company and many other military and water conservation areas and has attained the result of high quality, rapid speed and low cost. With successful application cases, its application is worth of expending to the construction of 1) artificial islands; 2) offshore drilling and producing platforms; 3) subsea pipelines; 4) pipeline crossing projects; 5) foundation in marsh; 6) underground projects, and 7) concrete projects in case of emergency which will require quick hardening and quick strength.It shall be noted that the research of undispersed underwater concrete still calls for systematic and necessary research into relevant materials and technologies.