2018 conference paper
Effect of seawater on the mechanical properties of cement grout used for formation of micropiles in marine applications
Ifcee 2018: innovations in ground improvement for soils, pavements, and subgrades, (296), 394–403.
UN Sustainable Development Goal Categories
14. Life Below Water
(OpenAlex)
Source: NC State University Libraries
Added: August 6, 2018
The deployment of ocean-based renewable energy generation devices, including those utilizing wind, waves, and tidal and ocean currents, requires the installation of cost-effective anchoring foundations. Micropiles provide a viable option for cost-effective subsea anchoring foundations. However, due to the lack of an acceptable approach for the subsea formation of micropiles in sandy soils, no cases that we are aware of have been presented in the literature. The research work reported in this article seeks to investigate the effect of seawater during mixing and curing on compressive strength (fc′) of cement grout for marine micropile anchor systems. Grout mixes are tested at three water-cement ratios (w/c) and in two different curing liquids. Specimens mixed with and cured in fresh water are designated by (ff), those mixed with and cured in seawater as (ss) and those mixed with fresh water and cured in seawater as (fs). A total of 162 cubes and 162 cylinders were cast and exposed to curing liquids for 7, 14, 28, and 90 days. The results showed an appreciable high and early fc′ gain of ss specimens compared to the baseline ff specimens. The rate of fc′ gain of ss specimens reduced slightly at low w/c ratio, but increased at higher w/c ratios (0.5 and 0.6). The reasons for such behavior are related to the accelerated rate of hydration of alite and belite due to the presence of chloride ions (Cl−) in seawater, and the transformation of ettringite (AFt) to monosulfate (AFm) or monochloroaluminate. Scanning electron microscopy (SEM) showed the formation of those crystals at discrete Cl− locations. The ff and fs specimens showed similar rate of fc′ gain (that was not affected by curing in seawater) due to the formation of impermeable layers of brucite [Mg (OH)2] and aragonite (CaCO3) beneath the surface of the fs specimens.