Non-Dispersible Underwater Concrete
Non-dispersible underwater concrete refers to the concrete mixed with the anti-washout admixture, which is a kind of water-soluble polymers with long-chain structures and strong absorption capacity. It can be used to solve the problems including placing a
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Non-Dispersible Underwater Concrete
Abstract Non-dispersible underwater concrete refers to the concrete mixed with the anti-washout admixture, which is a kind of water-soluble polymers with long-chain structures and strong absorption capacity. It can be used to solve the problems including placing and repairing of traditional concrete in underwater construction. Owing to the advantages of self-leveling, self-compacting, and little pollution to the environment water, the non-dispersible underwater concrete plays an important role in underwater and underground construction. Keywords Concrete
22.1
Non-dispersible Underwater Water-soluble polymer
Introduction
Concrete is still one of the most important and largest demand building materials for the construction of underwater engineering [1]. It has direct effect on the quality of engineering. Conventional concrete and water must be kept apart during transportation and placing in underwater engineering. When they inevitably come into contact, rapid interface flow must be minimized. Otherwise cement may be washed out to form a weak layer [2]. One of the typical placement methods for underwater concrete is the tremie method, in which a pipe is used to place concrete below water level. The lower end of the pipe is kept immersed in fresh concrete so that the rising concrete from the bottom displaces the water without washing out the cement paste. Because the concrete is required to flow over significant distances, it needs to keep strengths as low as 20% of the equivalent concrete cast in air can occur to ensure the satisfying flowability. However, some quality uncertainties inevitably exist in the tremie method due to the uncontrolled internal flow velocities and changes in the geometry of concrete and water interface. Therefore, development of nondispersible underwater concrete is necessary for underwater and underground construction. This makes it possible to design a mixture to reduce the quality uncertainties of concrete placing in the tremie method [1, 3].
© Springer Nature Singapore Pte Ltd. 2017 B. Han et al., Smart and Multifunctional Concrete Toward Sustainable Infrastructures, DOI 10.1007/978-981-10-4349-9_22
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Non-Dispersible Underwater Concrete
This chapter will give an overall introduction to the non-dispersible underwater concrete including its definition and classification, principles, properties, current progress, and applications.
22.2
Definition and Classification of Non-Dispersible Underwater Concrete
Non-dispersible underwater concrete, also named anti-washout underwater concrete, is the concrete mixed with anti-washout admixtures (AWAs). The AWAs belong to a kind of water-soluble polymers with long-chain structures and strong absorption capacity [1]. The non-dispersible underwater concrete can be classified as conventional non-dispersible underwater concrete and high-performance non-dispersible underwater concrete. Typical mixing proportion of the two types of non-dispersible underwater concrete is summarized in Table 22.1.
Tabl
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