Phase changes in cementitious materials exposed to saline solutions

Weerdt, Klaartje De; Bernard, Ellina; Kunther, Wolfgang; Pedersen, Mona Kyndi; Lothenbach, Barbara

doi:10.1016/j.cemconres.2022.107071

Cited by 37 publications

(17 citation statements)

References 107 publications

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“…The formation of M-S-H has also been observed at the surface of cements in contact with solutions with high magnesium concentrations such as seawater or the interstitial solution of clayey rocks [38,39]. Magnesium from the seawater or clay water reacts with the amorphous silica from the degradation of C-S-H in cement leading to the formation of M-S-H [40]. M-S-H has also been observed in Roman cements rich in chert and dolostone [41] indicating a long-term stability of M-S-H. Electron microprobe, SEM/EDS and TEM analyses indicate that M-S-H contains not only magnesium, silica, hydroxides and water but that aluminium, calcium and iron can be incorporated in its structure [42,43].…”

Section: Magnesium Silicate Cementsmentioning

confidence: 99%

MgO‐based binders

Lothenbach,

Bernard,

German

et al. 2023

ce papers

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To limit global temperature rise to below 2°C, we need to radically and rapidly change the way we build and use materials, since construction is responsible for 20‐40% of industrial CO2 emissions. Magnesium carbonate‐based cements have the potential to become a major carbon sink in construction industry, as CO2 will not be emitted during their production, but CO2 will rather be bound during hardening. Two different reaction mechanisms lead to setting and hardening of such HMC cements: i) hydration of MgO‐Mg‐carbonate, also in blends with silica and other mineral additions, in the presence of water or salt solutions (such as sodium bicarbonate solution) at ambient conditions or ii) carbonation hardening of MgO‐based systems at increased CO2 partial pressure and/or at increased temperatures.However, the utilization of hydrated magnesium carbonate and magnesium silicate cements is currently hampered by the lack of systematic experiments and of fundamental understanding of the factors affecting the hardening process, mechanical properties, long‐term behavior and durability. In particular, the role of temperature, relative humidity and addition of supplementary cementitious materials and/or industrial by‐products has not been systematically investigated. We need knowledge both on the practical side through systematic experiments with pastes, mortars and concretes as well as on a fundamental level through solubility and sorption experiments and thermodynamic modelling. In addition, reaction kinetics need to be optimized as well as the early formation of the preferred phases (stability enhancement) to develop efficient HMC cements for construction. Due to the socio‐economic relevance of cement and concrete, the impact of such “carbon”‐negative cements may go beyond a purely scientific one and lead to technological breakthroughs to the benefit of environment and society.

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Section: Magnesium Silicate Cementsmentioning

confidence: 99%

MgO‐based binders

Lothenbach,

Bernard,

German

et al. 2023

ce papers

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“…Such simplified thermodynamic models are very flexible and allow easy parameter variations and the results are in many cases comparable to full transport modelling, where parameters such as porosity and tortuosity have to be known in detail. A detailed comparison between the simplified modelling as used here and full transport modelling is given in [25,44].…”

Section: Thermodynamic Modelling Predictionsmentioning

confidence: 99%

The "Mica Crisis" in Donegal, Ireland – a Case of Internal Sulfate Attack?

Leemann¹,

Lothenbach²,

Münch³

et al. 2022

SSRN Journal

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“…Always use Ground Granulated Blast-furnace Slag (GGBS),Pulverized Fuel Ash PFA and micro silica MS (OPC + PFA/GGBS or OPC + PFA/GGBS + M.S). This is the best concrete you will get by this combination and this concrete is referred as durable concrete [5]. Always choose right mix design for right concrete.…”

Section: Introductionmentioning

confidence: 99%

Effects of Five Sources of Mixing Water on Durability of Concrete

Elshami

2023

Preprint

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This paper presents the experimental approach and the first results obtained as a result of the effect of five Sources of mixing water on produce more durable concrete. Five types of water were used, namely simulated acid rain (AR), Rain water (RW), tap water (TW), Zamzam water (ZW) and sea water (SW) as mixing water for ordinary portland cement concrete OPCC. The durability of these different types of water were tested toward their capacity to prevent the rebar corrosion. The results of workability, pH value, compressive strength, chlorides penetration and microstructure of different specimens mixed with each type of water were compared with those mixed with tap water (TW).

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Phase changes in cementitious materials exposed to saline solutions

Cited by 37 publications

References 107 publications

MgO‐based binders

MgO‐based binders

The "Mica Crisis" in Donegal, Ireland – a Case of Internal Sulfate Attack?

Effects of Five Sources of Mixing Water on Durability of Concrete

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