Utilization of cement-based materials for deep sea infrastructure

Utilization of Cement and Concrete for Deep Sea Infrastructure

“…Owing to the difficulty of accessing deep seas, easy construction methods, such as connecting precast members in situ like "LEGO blocks" are necessary to construct deepsea infrastructures [5,7]. Figure 6 depicts in situ connection using a cement mortar kit specifically designed for deep sea applications.…”

“…Decalcification of C-S-H, formation of thaumasite and M-S-H may occur at the surface as reported in [1,11], and these could cause disintegration of the specimen. Lots of pinhole-like popouts [5], where brucite, calcite and ettringite were detected in Fig. 2, were observed at the surface.…”

“…ions in seawater change the phase of PC hydrates such as dissolution of portlandite, decalcification of calcium silicate hydrate (C-S-H), and precipitation of magnesium silicate hydrate (M-S-H), brucite, ettringite and thaumasite. From the point of thermodynamic modelling, the influence of seawater on PC hydrates was calculated with GEMS3 and the Cemdata18 database [5]. Temperature and pressure were set at 20 °C and 0.1 MPa, predicting the changes in shallow seas, and at 2 °C and 35 MPa, predicting the changes in deep seas.…”

“…This paper reviews the current research on the use of cementitious materials in deep sea environments and highlights the potential for using new compositions to enhance its properties and applicability. Firstly, a series of laboratory and deep-sea field experiments as well as thermodynamic calculation have been conducted to evaluate the properties of conventional Portland cement (PC)-based materials under deep sea conditions [4,5]. The performance of different types of binder have also been evaluated by comparing the changes in physicochemical properties [6][7][8].…”