Blar i Institutt for konstruksjonsteknikk på forfatter "Lothenbach, Barbara"
-
Al uptake in calcium silicate hydrate and the effect of alkali hydroxide
Yan, Yiru; Ma, Bin; Miron, G. Dan; Kulik, D.A.; Scrivener, Karen; Lothenbach, Barbara (Peer reviewed; Journal article, 2022)The effect of Al and of pH on the structure of calcium silicate hydrate (C-S-H), the most important hydration product in Portland and blended cement, was studied at Ca/Si ~1.0. The presence of Al led to higher amounts of ... -
Analysis of the trend of pH changes of concrete pore solution during the hydration by various analytical methods
Natkunarajah, Kapilraj; Masilamani, Koneswaran; Maheswaran, Sithambaresan; Lothenbach, Barbara; Amarasinghe, D.A.S.; Attygalle, Dinesh (Peer reviewed; Journal article, 2022)The pH is an important parameter in concrete health monitoring. Many studies have been conducted to investigate the environmental elements that influence the pH value of concrete. This study focussed on the investigation ... -
Cement paste chemistry and its relation to concrete durability
Hemstad, Petter (Doctoral theses at NTNU;2023:258, Doctoral thesis, 2023) -
CemGEMS – An easy-to-use web application for thermodynamic modelling of cementitious materials
Kulik, Dmitrii A.; Winnefeld, Frank; Kulik, Anton; Miron, George Dan; Lothenbach, Barbara (Journal article; Peer reviewed, 2021)Thermodynamic equilibrium calculations for cementitious materials enable predictions of stable phases and solution composition. In the last two decades, thermodynamic modelling has been increasingly used to understand the ... -
CO2 storage in cement and concrete by mineral carbonation
Winnefeld, Frank; Leemann, Andreas; German, Alexander; Lothenbach, Barbara (Peer reviewed; Journal article, 2022)The production of cement is responsible for about 8% of man-made CO2 emissions. CO2 fixation by mineral carbonation in Ca- and Mg-rich raw materials such as cement-based concrete in various stages of its lifetime and ... -
The combined effect of potassium, sodium and calcium on the formation of alkali-silica reaction products
Shi, Zhenguo; Lothenbach, Barbara (Peer reviewed; Journal article, 2020)Both alkalis and calcium play essential roles in the formation of alkali-silica reaction (ASR) products. Investigation of their combined effect helps to better understand the conditions of ASR. In this study, samples with ... -
Comparing chloride ingress from seawater and NaCl solution in Portland cement mortar
De Weerdt, Klaartje; Lothenbach, Barbara; Geiker, Mette Rica (Journal article; Peer reviewed, 2019)This study investigates whether chloride ingress testing can be done using NaCl solution instead of seawater when assessing the performance of concrete in marine conditions. Seawater contains besides sodium and chlorine ... -
Early age impacts of CO2 activation on the tricalcium silicate and cement systems
Monkman, Sean; Sargam, Yogiraj; Naboka, Olga; Lothenbach, Barbara (Peer reviewed; Journal article, 2022)The early-age impacts of CO2 activation (using a dose of 0.3% CO2 by weight of cement) on two binder systems (tricalcium silicate and cement) were studied, principally across the first 3 h of hydration. The investigation ... -
Effect of alkali hydroxide on calcium silicate hydrate (C-S-H)
Yan, Yiru; Yang, Shen-Yu; Miron, G. Dan; Colings, Ines E.; L'Hôpital, Emilie; Skibsted, Jorgen; Winnefeld, Frank; Scrivener, Karen; Lothenbach, Barbara (Peer reviewed; Journal article, 2022)This paper investigates the effect of KOH and NaOH on C-S-H structure and solubility. Both KOH and NaOH have a similar effect, they increase pH values and silicon concentrations, and decrease calcium concentrations. At ... -
The effect of equilibration time on Al uptake in C-S-H
Barzgar, Sonya; Tarik, Mohamed; Ludwig, Christian; Lothenbach, Barbara (Peer reviewed; Journal article, 2021)Calcium silicate hydrate (C-S-H) is the main hydration product of Portland cements. The partial replacement of Portland cements by supplementary cementitious materials can result in C-S-H with lower Ca/Si ratios and more ... -
The effect of sodium hydroxide on Al uptake by calcium silicate hydrates (C-S-H)
Barzgar, Sonya; Lothenbach, Barbara; Tarik, Mohamed; Di Giacomo, Alessio; Ludwig, Christian (Peer reviewed; Journal article, 2020)To reduce the CO2 emissions from cement production, Portland cement (PC) is partially replaced by supplementary cementitious materials (SCM). Reactions of SCM with PC during hydration leads to the formation of Csingle ... -
Effect of temperature curing on properties and hydration of wollastonite blended magnesium potassium phosphate cements
Xu, Biwan; Winnefeld, Frank; Lothenbach, Barbara (Peer reviewed; Journal article, 2021)K-struvite, the main hydrate of magnesium potassium phosphate (MKP) cements, dehydrates at ~50 °C, thus elevated temperatures at service conditions could affect cement properties and durability. In this study, properties ... -
Fe(II) interaction with cement phases: Method development, wet chemical studies and X-ray absorption spectroscopy
Mancini, A.; Wieland, E.; Geng, G.; Lothenbach, Barbara; Wehrli, B.; Dähn, R. (Peer reviewed; Journal article, 2021)Fe(II) interaction with cement phases was studied by means of co-precipitation and sorption experiments in combination with X-ray absorption fine structure (XAFS) spectroscopy. Oxidation of Fe(II) was fast in alkaline ... -
Formation of shlykovite and ASR-P1 in concrete under accelerated alkali-silica reaction at 60 and 80 °C
Shi, Zhenguo; Park, Solmoi; Lothenbach, Barbara; Leemann, Andreas (Peer reviewed; Journal article, 2020)Three types of alkali-silica reaction (ASR) products, i.e., crystalline K-shlykovite, Na-shlykovite and nano-crystalline ASR-P1, have recently been synthesized at 80 °C. It is critical to verify the formation of these ASR ... -
Friedel's salt profiles from thermogravimetric analysis and thermodynamic modelling of Portland cement-based mortars exposed to sodium chloride solution
Shi, Zhenguo; Geiker, Mette Rica; Lothenbach, Barbara; De Weerdt, Klaartje; Garzón, Sergio Ferreiro; Enemark-Rasmussen, Kasper; Skibsted, Jørgen (Journal article; Peer reviewed, 2017)Thermogravimetric analysis (TGA), powder X-ray diffraction (XRD) and thermodynamic modelling have been used to obtain Friedel's salt profiles for saturated mortar cylinders exposed to a 2.8 M NaCl solution. Comparison of ... -
Influence of aluminum sulfate on properties and hydration of magnesium potassium phosphate cements
Xu, Biwan; Winnefeld, Frank; Ma, Bin; Rentsch, Daniel; Lothenbach, Barbara (Peer reviewed; Journal article, 2022)Aluminum sulfate shows a positive effect on preventing efflorescence of magnesium potassium phosphate (MKP) cements. Its influence on the MKP cement properties and hydration is explored in this study. Compared to a reference ... -
The influence of calcium sulfate content on the hydration of belite-calcium sulfoaluminate cements with different clinker phase compositions
Mrak, Maruša; Winnefeld, Frank; Lothenbach, Barbara; Dolenec, Sabina (Peer reviewed; Journal article, 2021)The influence of different amounts of gypsum on the hydration of a belite-rich and a ye'elimite-rich belite-calcium sulfoaluminate clinker (BCSA) was investigated. The hydration kinetics, phase assemblages and compressive ... -
Influence of wollastonite on hydration and properties of magnesium potassium phosphate cements
Xu, Biwan; Lothenbach, Barbara; Winnefeld, Frank (Journal article; Peer reviewed, 2020) -
Iron speciation in blast furnace slag cements
Mancini, A.; Lothenbach, Barbara; Geng, G.; Grolimund, D.; Sanchez, D.F.; Fakra, Sirine C.; Dähn, R.; Wehrli, B.; Wieland, E. (Peer reviewed; Journal article, 2021)Slag-containing pastes and concretes were analysed by element-specific synchrotron-based techniques to determine the speciation of iron on crushed materials through spatially resolved micro-spectroscopic studies. The ... -
A long-term study on structural changes in calcium aluminate silicate hydrates
Barzgar, Sonya; Yan, Yiru; Tarik, Mohamed; Skibsted, Jorgen; Ludwig, Christian; Lothenbach, Barbara (Peer reviewed; Journal article, 2022)Production of blended cements in which Portland cement is combined with supplementary cementitious materials (SCM) is an effective strategy for reducing the CO2 emissions during cement manufacturing and achieving sustainable ...