Expression of Cementitious Pore Solution and the Analysis of Its Chemical Composition and Resistivity Using X-ray Fluorescence

Chang, Marisol Tsui; Montanari, Luca; Suraneni, Prannoy; Weiss, Werner

doi:10.3791/58432-v

Cited by 3 publications

(2 citation statements)

References 5 publications

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“…As shown in Figure 1, the pore solution electrical conductivity varies from 0.05 to 0.35 S/cm as the chemistry of slags also varies (0–44 wt.% Al 2 O 3 , 24–68 wt.% CaO, and 0–28 wt.% MgO). These electrical conductivities are higher than those reported for early‐age pore solutions of Portland cements, which have mean values between 0.2 S/cm at early ages and 0.014 S/cm at later ages (i.e., 28 days) 26–28 . Here the influence of slag chemistry is observed to be increasingly significant as the degree of reaction of the slag progresses.…”

Section: Pore Solution Chemistry Of Alkali‐ and Salt‐activated Slag M...contrasting

confidence: 55%

“…These electrical conductivities are higher than those reported for early-age pore solutions of Portland cements, which have mean values between 0.2 S/cm at early ages and 0.014 S/cm at later ages (i.e., 28 days). [26][27][28] Here the influence of slag chemistry is observed to be increasingly significant as the degree of reaction of the slag progresses. Between 10% and 60% degrees of reaction (representing approximately the first 7 days of curing 11 ), the mean pore solution conductivity decreases by 18% (μ DOR = 60% = 0.28 S/cm) and 14% (μ DOR = 60% = 0.23 S/cm) for NaOH and Na 2 SiO 3 -activated slags, respectively (Figure 1A,B).…”

Section: 1mentioning

confidence: 94%

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How does the pore solution chemistry influence the passivation of reinforced alkali‐ and salt‐activated slag materials?

et al. 2023

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Service life predictions of reinforced concrete structures are underpinned by the passivation film chemistry, structure, and thickness. In this work, we present how the formation of passive films at the steel–concrete interface of reinforced alkali‐ and salt‐activated slag materials can be affected by the pore solution chemistry, namely, pH, Eh, and chemical composition. Thermodynamic simulations are used to illustrate the time‐dependent changes to the pore solution chemistry, where estimated electrical conductivities of the pore solution are used as a single‐value parameter to understand the solution complexity and capacity for charge transfer. A set of passivation reactions are proposed to understand the effects of OH− and HS− (reduced sulfur species) competition on the passivation pathways. These passivation reactions become more complex considering that a reducing pore solution might not establish until 3 days into the curing process—a crucial factor explaining the significant differences in the phase composition of passive films of activated slag materials (FeOOH, FeS). This study sheds light on recent progress in understanding these initial passivation reactions, emphasizing the essential role of material design and, therefore, the pore solution chemistry of these cements, along with significant insights for vital research and development concerning the corrosion durability of activated slag materials.

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Section: Pore Solution Chemistry Of Alkali‐ and Salt‐activated Slag M...contrasting

confidence: 55%

Section: 1mentioning

confidence: 94%

How does the pore solution chemistry influence the passivation of reinforced alkali‐ and salt‐activated slag materials?

et al. 2023

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Impact of curing solution on concrete surface resistivity and formation factor

Rios,

Rigaud,

Kopp

et al. 2024

Construction and Building Materials

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Influence of Loading Pressure and Sample Preparation on Ionic Concentration and Resistivity of Pore Solution Expressed from Concrete Samples

Montanari

Tanesi

Kim

et al. 2021

Journal of Testing and Evaluation

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Pore solution expression is an established method to obtain samples of the liquid phase from cementitious systems. This experimental method applies pressure to a cementitious sample, forcing its liquid phase out of the pores. By collecting and studying the liquid phase in cementitious systems, it is possible to obtain information on its ionic concentrations. The ionic concentrations can be used for modeling calibrations and to estimate the resistivity of the pore solution. When the bulk resistivity of concrete is normalized by the pore solution resistivity, it is possible to determine the formation factor. The formation factor is related to the transport properties of the concrete and, as such, it can be used to estimate the rates of transport of ionic species within a concrete structure. The formation factor is currently being included in AASHTO PP84, Standard Practice for Developing Performance Engineered Concrete Pavement Mixtures, as an indicator of transport properties for quality control operations. Pore solution expression is included as one of the available procedures of AASHTO PP84-19 to determine the pore solution electrical resistivity. Previous studies on paste and mortar samples have demonstrated that increased loading pressure during the pore solution expression might impact the final ionic concentrations of the expressed solution. This study aims to verify if the pore solutions of concrete specimens are also influenced by the selected loading pressure and whether the potential consequent change in the measured ionic concentrations of the solution also has an impact on its resistivity. No appreciable trend in increased solubility was observed for the range of applied normal pressures between 600 and 985 MPa. Cyclic loading regimes increased the variability of alkali solubility. Sample preparation, in some cases, influenced the water content of the sample and induced unwanted alteration on the ionic concentrations of the mixtures under study.

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Expression of Cementitious Pore Solution and the Analysis of Its Chemical Composition and Resistivity Using X-ray Fluorescence

Cited by 3 publications

References 5 publications

How does the pore solution chemistry influence the passivation of reinforced alkali‐ and salt‐activated slag materials?

How does the pore solution chemistry influence the passivation of reinforced alkali‐ and salt‐activated slag materials?

Impact of curing solution on concrete surface resistivity and formation factor

Influence of Loading Pressure and Sample Preparation on Ionic Concentration and Resistivity of Pore Solution Expressed from Concrete Samples

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