Thermal Conductivity of Seawater Cement-Based Materials: Effect of Water-to-Cement Ratio, Curing Age, Sand Content, and Porosity

Abstract

The microstructures of seawater cement-based materials normally are influenced by the salinity in seawater, which could result in different properties. The thermal conductivity (λ-value) of seawater cement-based materials is a key input parameter for the heat transfer analysis. However, few studies have been conducted on this issue. This study investigated the λ-value of seawater cement-based materials using experimental and numerical methods. The influences of water-to-cement (w/c) ratio, curing age, and sand content on the λ-value of seawater cement-based materials were examined experimentally. Then a three-dimensional mesoscale finite-element model was established to assess the influences of pore size and porosity on the λ-value of cement-based materials. It was found that the λ-value of seawater cement-based materials increases with increasing curing age or sand content, and a low w/c ratio contributes to a high λ-value, similar to that of the tap-water cementitious material. The λ-value of seawater cement paste with curing ages of 1 and 7 days was slightly greater than that of the tap-water cement paste. However, no significant difference was found between the λ-values of the 28-day seawater and tap-water cement pastes. Pore size had a negligible influence on the λ-value. The λ-value of cement-based materials decreased with increasing porosity, and the decrease in λ-value of cement-based materials with pores filled with air was more significant than that with pores filled with water, indicating that the pore-water saturation has a great effect on the thermal conductivity.