Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Experimental studies of ion transport in cementitious materials under partially saturated conditions
Cement production is responsible for a significant portion of manmade CO2 emissions. This motivates the development of cementitious binders with a lower carbon footprint. Considering the emissions in a longer perspective, the durability of concrete structures is absolutely essential. Most degradation of concrete structures is closely related to both moisture transport and ion transport. Many studies have investigated these areas under saturated conditions. Owing to varying exposure conditions and self-desiccation, most concrete structures undergo large variations in moisture state during their service life. The coupling between ionic transport and moisture transport in cementitious materials under partially saturated conditions is still poorly understood. This project aimed to contribute to the knowledge in this area.Service life models can be used to predict the performance of the material over time, but fundamental understanding of the underlying physical and chemical relations is critical for the development of accurate models. In this project, these physical relations of unsaturated ion transport were studied experimentally. The moisture dependency of ionic diffusion and ionic convection was investigated in two studies. The experimental investigations were performed on mortars with two water to binder ratios (0.38 and 0.53) and with four binders (OPC, 95% OPC + 5% silica fume, 60% OPC + 40% GGBFS, and 30% OPC + 70% GGBFS). In the diffusion study, resistivity measurements and the Nernst-Einstein equation were used to evaluate the moisture dependency of the chloride diffusion coefficient, i.e., DCl(RH) and DCl(S). Desorption isotherms were determined using a gravimetric box method, and the conductivity of pore solutions was evaluated in two different ways. First, a simplified method was used. The limitation of this method is that it can only assess the pore solution composition for the OPC mortars. Second, a thermodynamic modeling tool, GEMS, was used to assess the pore solution composition and the chloride ...
Experimental studies of ion transport in cementitious materials under partially saturated conditions
Cement production is responsible for a significant portion of manmade CO2 emissions. This motivates the development of cementitious binders with a lower carbon footprint. Considering the emissions in a longer perspective, the durability of concrete structures is absolutely essential. Most degradation of concrete structures is closely related to both moisture transport and ion transport. Many studies have investigated these areas under saturated conditions. Owing to varying exposure conditions and self-desiccation, most concrete structures undergo large variations in moisture state during their service life. The coupling between ionic transport and moisture transport in cementitious materials under partially saturated conditions is still poorly understood. This project aimed to contribute to the knowledge in this area.Service life models can be used to predict the performance of the material over time, but fundamental understanding of the underlying physical and chemical relations is critical for the development of accurate models. In this project, these physical relations of unsaturated ion transport were studied experimentally. The moisture dependency of ionic diffusion and ionic convection was investigated in two studies. The experimental investigations were performed on mortars with two water to binder ratios (0.38 and 0.53) and with four binders (OPC, 95% OPC + 5% silica fume, 60% OPC + 40% GGBFS, and 30% OPC + 70% GGBFS). In the diffusion study, resistivity measurements and the Nernst-Einstein equation were used to evaluate the moisture dependency of the chloride diffusion coefficient, i.e., DCl(RH) and DCl(S). Desorption isotherms were determined using a gravimetric box method, and the conductivity of pore solutions was evaluated in two different ways. First, a simplified method was used. The limitation of this method is that it can only assess the pore solution composition for the OPC mortars. Second, a thermodynamic modeling tool, GEMS, was used to assess the pore solution composition and the chloride ...
Experimental studies of ion transport in cementitious materials under partially saturated conditions
Olsson, Nilla (Autor:in)
01.01.2018
Hochschulschrift
Elektronische Ressource
Englisch
Engineering and Technology , Cement , Bruk , Betong , Jontransport , Fukttransport , Sorptionsisoterm , Tillsatsmaterial , Kiselstoft , Masugnsslagg , Ciment , Mortier , Béton , Transport ionique , Transport d'humidité , Sorption de vapeur d'eau , Additions minérales , Fumée de silice , Laitier de haut fourneau granulé moulu , Mortar , Concrete , Ion transport , moisture transport , Water vapor sorption , Supplementary cementitious materials (SCMs) , Silica fume , Ground granulated blast furnace slag
Chloride diffusion in partially saturated cementitious material
| Elsevier | 2002
Chloride diffusion in partially saturated cementitious material
| Online Contents | 2003
Chloride diffusion in partially saturated cementitious material
| British Library Online Contents | 2003
Chloride diffusion in partially saturated cementitious material
| Tema Archiv | 2002