A Comprehensive Study of the Mechanical and Durability Properties of High-Performance Concrete Materials for Grouting Underwater Foundations of Offshore Wind Turbines

Abstract

With the increasing importance of offshore wind turbines, a critical issue in their construction is the high-performance concrete (HPC) used for grouting underwater foundations, as such materials must be better able to withstand the extremes of the surrounding natural environment. This study produced and tested 12 concrete sample types by varying the water/binder ratio (0.28 and 0.30), the replacement ratios for fly ash (0%, 10%, and 20%) and silica fume (0% and 10%), as substitutes for cement, with ground granulated blast-furnace slag at a fixed proportion of 30%. The workability of fresh HPC is discussed with setting time, slump, and V-funnel flow properties. The hardened mechanical properties of the samples were tested at 1, 7, 28, 56, and 91 days, and durability tests were performed at 28, 56, and 91 days. Our results show that both fly ash (at 20%) and silica fume (at 10%) are required for effective filling of interstices and better pozzolanic reactions over time to produce HPC that is durable enough to withstand acid sulfate and chloride ion attacks, and we recommend this admixture for the best proportioning of HPC suitable for constructing offshore wind turbine foundations under the harsh underwater conditions of the Taiwan Bank. We established a model to predict a durability parameter (i.e., chloride permeability) of a sample using another mechanical property (i.e., compressive strength), or vice versa, using the observable relationship between them. This concept can be generalized to other pairs of parameters and across different parametric categories, and the regression model will make future experiments less laborious and time-consuming.

Complex Modulus characterization of an Optimized Binder with SCMs: proposition of an enhanced Cement formulation to improve Stiffness Behavior and Durability of Mortars and Concretes

“…The results of the complex modulus tests demonstrated that the optimized binder formulation, M2, consistently exhibited a higher complex modulus than M1 across all sweep frequencies, with an average value of 15.48 GPa. This nding indicates that M2 has a higher stiffness than M1, which could potentially improve the material's durability and resistance to pathological manifestations such as cracking (Kuo & Zhuang, 2021;Myrtja et al, 2021c).…”

“…As reported by literature, the use of silica fume (SF) in concrete can signi cantly enhance its compressive strength and elastic modulus, essential properties in those applications (Fattouh & Elsayed, 2023;Keerio et al, 2022;Boukhelf et al, 2021). Kuo & Zhuang (2021) also presented evaluations on high-performance concrete for aerogenerators foundations. It was found that a higher modulus of elasticity, compared to the usual values for normalstrength concrete, were more suitable for that application having an improved resistance to the mechanical and environmental loads incident from the aerogenerators' usual operation.…”

“…It is important to note that despite being called the dynamic modulus, there are no inertial effects involved. (Brinson & Brinson, 2008;Kuo & Zhuang, 2021;Saucedo et al, 2013b).…”

Study on macro performance and micro-analysis of high strength grouting material

“…The particularity of grouting of offshore wind power lies in that the offshore fan is under the action of reciprocating random load, and the grouting connection section is under the combined action of axial force, bending moment, torque and other loads, which makes the grouting material work in a complex stress state. Different from traditional grouting materials, wind power grouting materials are required to have higher fluidity and higher stability in the pumping stage, and also to have high mechanical properties [11,12]. Currently, researchers have conducted extensive research on the fluidity, volume stability, and mechanical properties of grouting materials.…”

Complex Modulus characterization of an optimized binder with SCMs: proposition of an enhanced cement formulation to improve stiffness behaviorand durability of mortars and concretes

“…The imaginary part corresponds to the material's characteristic to dissipate energy, also called the loss modulus. It is important to note that despite being called the dynamic modulus, there are no inertial effects involved (Brinson & Brinson, 2008;Kuo & Zhuang, 2021;Saucedo et al, 2013b)…”