Dielectric properties of the pore solution in cement-based materials

Abstract

Dielectric properties are intimately related to the content and composition of the liquid phase present in micro-and mesoporous materials. The presence of ions is recognized to affect the dielectric response of electrolytes in a complex way that depends on the ion-water and ion-ion interactions and respective concentrations. Pore solutions in cement-based materials are complex and age-dependent exhibiting different ion pair states, which make them an interesting candidate for the study of the complex pore solution found in geomaterials in general. Here, we study the dielectric properties of bulk aqueous solutions representative of the pore solution found in cement-based materials using molecular dynamics simulations. Broadband dielectric spectra and frequency-dependent conductivities are provided. A mean field upscaling strategy is deployed to compute the dielectric response at cement-paste scale. In cement-based materials, the measurement of dielectric properties can be used for non-destructive monitoring of concrete structures conditions and to unravel details of the hierarchical pore structure of the material, notably at early-age when the microstructure of the material changes significantly. Our results can be used in the interpretation of high frequency electromagnetic methods, such as ground-penetrating radar, enhancing the quality of interpretation and improving the confidence in the corresponding results.

Homogenization of nonaging basic creep of cementitious materials: A multiscale modeling benchmark

“…The multiscale Model 4M is based on a 4-scale representation of concrete with a hydrate matrix, hence the acronym "4M". This representation has been used to upscale thermal [40] and electromagnetic [41,42] properties of cement-based materials and is a simplified version of the modeling approach presented in Ref. The microstructure of the hydrate foam consists of a hydrate matrix and spherical inclusions representing capillary pores.…”

CSI (Cement Science Investigation): Using Machine Learning to Guess the OPC Pastes Composition from the Elastic Response

“…2A. Similar representations were successfully used in previous work to estimate mechanical [16,17], thermal [18], and electromagnetic properties [19,20] of cement pastes.…”

“…Among the variety of possibility to guide the plan of experiments [20], the strategy deployed here to identify the domain in the 7-dimension space of input variables is to take a derivative of the ordered components of each input vector. The higher the peak in the derivative, the most significant is the domain with missing data.…”

Electromagnetic Properties of Concrete: Bottom-Up Modeling from the Molecular Scale

“…As discussed in ref. [10], the contribution of water-water interactions, are predominant in the dielectric response. The dielectric spectra can be fitted using the Cole-Cole model with the parameters gathered in Table 1.…”

“…The self-consistent scheme was used to get the effective properties of the cement paste since it captures the complex liquid-solid transition observed in cement paste at early-ages [10,11]. Mori-Tanaka is deployed to homogenize mortar and concrete scales, in which a clear matrix/inclusion morphology is observed.…”