Explanipedia

Critical review of the properties of MgO - magnesium carbonate cements Open

Barbara Lothenbach, Zeyu Zhou, Alexander German, Paula Montserrat-Torres · 2025

Simultaneous formation and decomposition of calcium silicate hydrate under carbonation in water Open

Yuxi Cai, Pan Feng, Xin Liu, Xuyan Shen, Barbara Lothenbach · 2025

Carbonation curing captures CO₂ while rapidly gaining strength, as calcium silicate hydrate (C-S-H) precipitates and carbonates simultaneously. The simultaneous formation and decomposition of C-S-H under carbonation was investig…

Report of RILEM TC 301-ASR: relation between pore solution composition and ASR expansion Open

Barbara Lothenbach, Miriam E. Krüger, Maxime Ranger, Ana Bergmann, Petter Hemstad , et al. · 2025

An important parameter determining the risk of alkali-silica reaction (ASR) in concrete is the availability of alkali ions as they are closely related to the OH − concentration in the pore solution. Comparison of concrete or mortar expansi…

Enhancing slag reaction in cement blends using calcium formate and sodium metasilicate activators Open

Adrian-Alexandru Pîrvan, Barbara Lothenbach, Miriam Schröder, Michael G. Schwendinger, Joumana Yammine‐Malesys , et al. · 2025

The reactivity of blast furnace slag in blended cements is rather low at early ages, and thus accelerators are usually used for certain applications. This study describes the effects of accelerators, namely calcium formate and sodium metas…

Effect of Mg on xonotlite structure and stability Open

Serena Mingione, Daniel Jansen, Frank Winnefeld, Sergey V. Churakov, Barbara Lothenbach · 2025

Minor constituents such as clays or dolomite might be present in the raw materials used for the synthesis of xonotlite (Ca₆Si₆O₁₇(OH)₂). These impurities can introduce additional elements (e.g., …

Hydrotalcite-pyroaurite solid solution in cement system: Molecular structure and thermodynamic properties Open

Dengquan Wang, Yue Zhang, John L. Provis, Barbara Lothenbach, Sergey V. Churakov , et al. · 2025

Hydrotalcite-pyroaurite solid solutions, which are common minerals both in nature and in modern cementitious materials, hold significant potential for waste immobilization and cement properties yet remain insufficiently studied. In this wo…

Zn2+ as a dopant to stabilize hydrated magnesium carbonates Open

Hoang Nguyen, Nirrupama Kamala Ilango, Frank Winnefeld, Barbara Lothenbach, Päivö Kinnunen · 2025

The formation of solid solutions of Mg‑carbonates incorporating Zn²⁺ was investigated. The presence of Zn retarded the reaction of brucite at the early stages but increased its reaction in the long-term. The initially formed nes…

Modelling and visualizing the impact of metakaolin on the alkali concentration in cement paste pore solution Open

Ana Bergmann, Klaartje De Weerdt, Maxime Ranger, Miriam E. Krüger, Petter Hemstad , et al. · 2025

This study investigates the effects of replacing Portland cement (PC) with metakaolin (MK) on the pore solution composition of cementitious binders. Using the empirical Taylor model and a thermodynamic model (GEMS), the required replacemen…

Zinc acetate as a set retarder for magnesium potassium phosphate cements Open

Biwan Xu, Frank Winnefeld, Barbara Lothenbach · 2025

The development of not-toxic retarders with a high retardation efficiency is crucial for a sustainable development of high-performance magnesium potassium phosphate (MKP) cement-based materials. Zinc acetate is such a promising new set ret…

A connection between structure and reactivity in alkali-modified calcium aluminosilicate glasses for sustainable cements Open

René Mossing Thomsen, Shuai Nie, Barbara Lothenbach, Lars R. Jensen, Asbjørn Haaning Nielsen , et al. · 2025

Alkali-carbonate reaction in concrete - Microstructural consequences and mechanism of expansion Open

Andreas Leemann, Beat Münch, Barbara Lothenbach, Ellina Bernard, Cassandra Trottier , et al. · 2025

A detailed microstructural investigation of a concrete expanding due to alkali‑carbonate reaction (ACR) shows that the cement paste adjacent to reactive aggregate particles is carbonated, which leads to a sulfur redistribution resembling i…

Synthesis and thermodynamic data of acetate-containing giorgiosite – a novel hydrated magnesium carbonate Open

Hoang Nguyen, Ellina Bernard, Frank Winnefeld, Barbara Lothenbach, Päivö Kinnunen · 2025

Organic additives play important roles in enhancing the formation of Mg‑carbonates and reaction kinetics in MgO-based cements. However, little is known about the influences of organics on the formation pathways of carbonate phases and whet…

Uranium(VI) retention by calcium (alumino)silicate hydrates – Impact of temperature and ionic strength Open

Katja Schmeide, Nina Huittinen, Salim Shams Aldin Azzam, Frank Bok, Erica Brendler , et al. · 2025

Calcium aluminosilicate hydrates (C-A-S-H) are the main hydration products of cement formulations with Al-rich additives such as blast furnace slags, fly ashes or calcined clays. We studied systematically the effect of Al substitution on b…

Effect of nesquehonite and silica on magnesia-silicate‑carbonate cements Open

Zeyu Zhou, Ellina Bernard, Barbara Lothenbach · 2025

Cements based on hydrated magnesium carbonates are an alternative binder system with high CO₂ sequestration ability. The present study examines the effect of silica, a by-product of MgO production from magnesium-silicate rocks, …

Thermodynamic modeling: Success in cement science – Untapped potential in corrosion research Open

Fabio E. Furcas, Barbara Lothenbach, Shishir Mundra, O. Burkan Isgor, Mette Rica Geiker , et al. · 2025

For more than a century, the corrosion of steel in concrete has prevailed as a complex and yet poorly understood phenomenon, with many durability design approaches relying on phenomenological or semi-empirical service life models. The incr…

Report of RILEM TC 301-ASR: Modelling the impact of SCMs, alkali level and w/b ratio on alkali concentration in pore solution Open

Klaartje De Weerdt, Maxime Ranger, Miriam E. Krüger, Ana Bergmann, Petter Hemstad , et al. · 2025

Supplementary cementitious materials (SCMs) can mitigate alkali-silica reaction by lowering the alkali metal concentration in the pore solution. This is a theoretical study on the applicability of a thermodynamic model (GEMS) and the empir…

Navigating the Complexities of Multiple Redox State Interactions in Aqueous Systems Open

Shishir Mundra, Mohit Pundir, Barbara Lothenbach, David S. Kammer, Ueli Angst · 2025

Numerous aqueous systems host elements in multiple redox states, with wide ranging implications such as their influence on the formation/dissolution of minerals, water toxicity, and nutrient cycling. To uncover governing mechanisms and com…

Thermodynamic Simulation-Assisted Design of the Electrolytic Manganese Residue-Slag-Ca(Oh)2 Cementitious System: Reaction and Mn Immobilization Open

Lang Pang, Jianwei Sun, John L. Provis, Barbara Lothenbach, Bin Ma , et al. · 2025

Zinc Acetate as a Set Retarder for Magnesium Potassium Phosphate Cements Open

Biwan Xu, Frank Winnefeld, Barbara Lothenbach · 2025

Effect of Mg on Xonotlite Structure and Stability Open

Serena Mingione, Daniel Jansen, Frank Winnefeld, Sergey Churakov, Barbara Lothenbach · 2025

Enhancing Slag Reaction in Cement Blends Using Calcium Formate and Sodium Metasilicate Activators Open

Adrian Alexandru Pîrvan, Barbara Lothenbach, Miriam Schröder, Michael G. Schwendinger, Joumana Yammine‐Malesys , et al. · 2025

Hydrotalcite-Pyroaurite Solid Solution in Cement System: Molecular Structure and Thermodynamic Properties Open

Dengquan Wang, Yue Zhang, John L. Provis, Barbara Lothenbach, Sergey V. Churakov , et al. · 2025

Zn2+ as a Dopant to Stabilize Hydrated Magnesium Carbonates Open

Hoang Nguyen, Nirrupama Kamala Ilango, Frank Winnefeld, Barbara Lothenbach, Päivö Kinnunen · 2025

Impact of nesquehonite on hydration and strength of MgO-based cements Open

Paula Montserrat-Torres, Frank Winnefeld, Barbara Lothenbach · 2024

Hydrated magnesium carbonate cements prepared from MgO and carbonates such as hydromagnesite (Mg₅(CO₃)₄(OH)₂·4H₂O) or nesquehonite (MgCO₃ˑ3H₂O) have potential for…

Pyroaurite-like phases (Mg-Fe3+ LDH) synthesis and solubility Open

Ellina Bernard, Barbara Lothenbach, Rupert J. Myers, Marcus Yio · 2024

This study explores different methods for precipitating carbonated Mg-Fe³⁺ layered double hydroxides (LDHs) with Mg/Fe³⁺ ratios ranging from 2 to 2.5. Two synthesis approaches were investigated: a) CO₃-Mg-F…

Changes in cement paste during accelerated mortar bar testing for pyrrhotite containing aggregate Open

Klaartje De Weerdt, Mahsa Bagheri, Jan Lindgård, H. Lindstad, A. Rodrigues , et al. · 2024

The accelerated mortar bar test (AMBT) for pyrrhotite (Fe_1-xS) containing aggregates accelerates expansion using two regimes: Phase I, during which Fe_1-xS oxidation to iron hydroxide is accelerated by bleach and stora…

Effect of temperature on the solubility of xonotlite Open

Serena Mingione, Daniel Jansen, Frank Winnefeld, Sergey V. Churakov, Barbara Lothenbach · 2024

Xonotlite forms under hydrothermal conditions and it dehydrates to β-wollastonite between 770 and 800 °C under atmospheric pressure. The solubility of xonotlite is poorly known, as the experimental datasets reported in literature differ by…

Speciation Controls the Kinetics of Iron Hydroxide Precipitation and Transformation at Alkaline pH Open

Fabio E. Furcas, Shishir Mundra, Barbara Lothenbach, Ueli Angst · 2024

[Image: see text] The formation of energetically favorable and metastable mineral phases within the Fe–H(2)O system controls the long-term mobility of iron complexes in natural aquifers and other environmentally and industrially relevant s…

Thermodynamic modeling of alkali-activated fly ash paste Open

Yun Chen, Bin Ma, Jiayi Chen, Zhenming Li, Xuhui Liang , et al. · 2024

Previously, the lack of a thermodynamic database for N-(C-)A-S-H gel limited the application of thermodynamic modeling to alkali-activated fly ash (AAFA). This study pioneers thermodynamic modeling of AAFA using a recently developed thermo…

Defective homes in Donegal, Ireland: Effect of exposure conditions and concrete quality on pyrrhotite oxidation and internal sulfate attack Open

Andreas Leemann, Beat Münch, Barbara Lothenbach, Frank Winnefeld, P Dunlop · 2024

Thousands of homes in County Donegal, Ireland, built from concrete blocks, are damaged by extensive cracks and crumbling that occurred a few years after construction. Recently, research has shown that pyrrhotite oxidation triggering intern…

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