Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Damage in cement pastes exposed to $ MgCl_{2} $ solutions
https://orcid.org/0000-0002-2583-5296
Abstract Magnesium chloride ($ MgCl_{2} $) reacts with cement pastes resulting in calcium leaching and the formation of calcium oxychloride, which can cause damage. This paper examines the damage in different cement pastes exposed to $ MgCl_{2} $ solutions. Volume change measurement and low temperature differential scanning calorimetry are used to characterize the formation of calcium oxychloride. Thermogravimetric analysis and X-ray fluorescence are used to quantify calcium leaching from Ca(OH)2 and C-S-H. The ball-on-three-balls test is used to quantify the flexural strength reduction. Calcium oxychloride can form in cement pastes exposed to $ MgCl_{2} $ solutions with a (Ca(OH)2/$ MgCl_{2} $) molar ratio larger than 1. As the $ MgCl_{2} $ concentration increases, two-stages of flexural strength reduction are observed in the plain cement pastes, with the initial reduction primarily due to calcium leaching from Ca(OH)2 and the additional reduction due to the calcium leaching from C-S-H (at $ MgCl_{2} $ concentrations above 17.5 wt%). For the cement pastes containing fly ash, there is a smaller reduction in flexural strength as less Ca(OH)2 is leached, while no additional reduction is observed at high $ MgCl_{2} $ concentrations due to the greater stability of C-S-H with a lower Ca/Si ratio. The addition of fly ash can mitigate damage in the presence of $ MgCl_{2} $ solutions.
Damage in cement pastes exposed to $ MgCl_{2} $ solutions
https://orcid.org/0000-0002-2583-5296
Abstract Magnesium chloride ($ MgCl_{2} $) reacts with cement pastes resulting in calcium leaching and the formation of calcium oxychloride, which can cause damage. This paper examines the damage in different cement pastes exposed to $ MgCl_{2} $ solutions. Volume change measurement and low temperature differential scanning calorimetry are used to characterize the formation of calcium oxychloride. Thermogravimetric analysis and X-ray fluorescence are used to quantify calcium leaching from Ca(OH)2 and C-S-H. The ball-on-three-balls test is used to quantify the flexural strength reduction. Calcium oxychloride can form in cement pastes exposed to $ MgCl_{2} $ solutions with a (Ca(OH)2/$ MgCl_{2} $) molar ratio larger than 1. As the $ MgCl_{2} $ concentration increases, two-stages of flexural strength reduction are observed in the plain cement pastes, with the initial reduction primarily due to calcium leaching from Ca(OH)2 and the additional reduction due to the calcium leaching from C-S-H (at $ MgCl_{2} $ concentrations above 17.5 wt%). For the cement pastes containing fly ash, there is a smaller reduction in flexural strength as less Ca(OH)2 is leached, while no additional reduction is observed at high $ MgCl_{2} $ concentrations due to the greater stability of C-S-H with a lower Ca/Si ratio. The addition of fly ash can mitigate damage in the presence of $ MgCl_{2} $ solutions.
Damage in cement pastes exposed to $ MgCl_{2} $ solutions
https://orcid.org/0000-0002-2583-5296
Abstract Magnesium chloride ($ MgCl_{2} $) reacts with cement pastes resulting in calcium leaching and the formation of calcium oxychloride, which can cause damage. This paper examines the damage in different cement pastes exposed to $ MgCl_{2} $ solutions. Volume change measurement and low temperature differential scanning calorimetry are used to characterize the formation of calcium oxychloride. Thermogravimetric analysis and X-ray fluorescence are used to quantify calcium leaching from Ca(OH)2 and C-S-H. The ball-on-three-balls test is used to quantify the flexural strength reduction. Calcium oxychloride can form in cement pastes exposed to $ MgCl_{2} $ solutions with a (Ca(OH)2/$ MgCl_{2} $) molar ratio larger than 1. As the $ MgCl_{2} $ concentration increases, two-stages of flexural strength reduction are observed in the plain cement pastes, with the initial reduction primarily due to calcium leaching from Ca(OH)2 and the additional reduction due to the calcium leaching from C-S-H (at $ MgCl_{2} $ concentrations above 17.5 wt%). For the cement pastes containing fly ash, there is a smaller reduction in flexural strength as less Ca(OH)2 is leached, while no additional reduction is observed at high $ MgCl_{2} $ concentrations due to the greater stability of C-S-H with a lower Ca/Si ratio. The addition of fly ash can mitigate damage in the presence of $ MgCl_{2} $ solutions.
Damage in cement pastes exposed to $ MgCl_{2} $ solutions
Qiao, Chunyu (Autor:in) / Suraneni, Prannoy (Autor:in) / Tsui Chang, Marisol (Autor:in) / Weiss, Jason (Autor:in)
2018
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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