Round Robin Test for Defining an Accurate Protocol to Measure the Pore Fluid pH of Low-pH Cementitious Materials

Alonso, C.; Calvo, José Luis García; Pettersson, S.; Puigdomènech, I.; Cuñado, Miguel Ángel; Vuorio, Marja; Weber, Hans‐Peter; Ueda, Hisashi; Naito, Morimasa; Walker, Colin; Takeshi, Y.; Cau-dit-Coumes, Céline

doi:10.1007/978-1-4614-3445-0_22

Cited by 16 publications

(18 citation statements)

References 12 publications

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“…Figure 4 shows the results of pH evolution in the suspensions of MKPC pastes with a 1:1 solid/liquid ratio as a function of the curing time, up to 90 days [ 38 ]. The pH is an important parameter for the encapsulation of reactive metals due to its influence on corrosion processes.…”

Section: Resultsmentioning

confidence: 99%

“…The pH of the porewater solution of the MKPC pastes was measured at up to 95 days of curing. Samples were crushed and powder grinded, then pH was measured in suspensions stirred for 5 min with degasified deionized water and with a water/solid ratio of 1 [ 38 ]. Determination of the porewater for pH determination by porepressing, such as described in [ 39 ], was discarded because of the high density and low porosity of these systems.…”

Section: Methodsmentioning

confidence: 99%

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Evaluation of Fillers for Magnesium Potassium Phosphate Cement (MKPC) for the Encapsulation of Low and Intermediate Level Metallic Radioactive Wastes

et al. 2023

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This study investigates the effect of coal fly ash (FA), wollastonite (WO), pumice (PM), and metakaolin (MK) as filler materials in the rheological, mechanical, chemical, and mineralogical properties of a magnesium potassium phosphate cement (MKPC), designed for the encapsulation of low and intermediate level radioactive wastes containing reactive metals. Workability, compression strength, dimensional stability, pH, chemical composition, and mineralogical properties were studied in different pastes and mortars of MKPC with a fixed molar ratio of MgO/KH2PO4 = 1. No new mineral phases were found with the addition of the fillers, denoting their low chemical impact on the MKPC system. Moreover, all formulations with a water/cement mass ratio of <0.65 presented compressive strengths higher than 30 MPa after 90 days, and pH values lower than 8.5, corresponding to the passivation zone of aluminum corrosion.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Evaluation of Fillers for Magnesium Potassium Phosphate Cement (MKPC) for the Encapsulation of Low and Intermediate Level Metallic Radioactive Wastes

et al. 2023

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“…Afterward, parts of the remaining mortar and the gypsum layer were ground for measuring their pH by the ex-situ extraction method [ 15 , 20 , 21 ]. For that purpose, the same amount of powder and of decarbonated distilled water (boiled and bubbled with argon to remove carbon dioxide) were mixed by magnetic stirring in a closed container during 24 h. The pH was measured by potentiometry with an Inlab Expert Pro pH combined electrode and a SevenMulti meter, both from Mettler Toledo (Columbus, OH, USA).…”

Section: Resultsmentioning

confidence: 99%

“…In the in-situ leaching method, a hole is drilled in the concrete, the hole is filled with distilled water, and the pH is measured after sufficient time of equilibration [ 18 , 19 ]. The ex-situ extraction consists of grinding the mortar or concrete to fine powder, mixing it with decarbonated distilled water, and measuring the pH after an equilibration time [ 20 , 21 , 22 , 23 ]. pH indicators are also used particularly for determining carbonation in concrete [ 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

New Sensors for Monitoring pH and Corrosion of Embedded Steel in Mortars during Sulfuric Acid Attack

Sampaio

Bastos

Ferreira

2022

Sensors

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The sulfuric acid attack is a common form of degradation of reinforced concrete in contact with industrial wastewater, mine water, acid rain, or in sewage treatment stations. In this work, new pH-sensitive IrOx electrodes were developed for monitoring the pH inside mortar or concrete. To test their ability, the pH sensors were embedded in mortar samples at different depths and the samples were exposed to sulfuric acid solution. In another set of experiments, iron wires were placed at the same depths inside similar mortar samples and their corrosion was monitored as the acid attacked the mortar. Severe acid attack led to cement dissolution and formation of gypsum. The new pH sensors succeeded in measuring the pH changes inside the mortars. The pH gradient, from the high acid environment to the high alkaline mortar interior, occurred in a narrow region. Corrosion of the iron electrodes started only when the acidic solution was in their close vicinity.

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“…Hence, a slight pH decrease occurred passing from re-alkalised concrete to re-carbonated concrete (on average from 10.6 to 10.3), however it was much smaller than that occurred passing from alkaline to carbonated concrete (on average from 12.4 to 8.9). Although measuring the pH of concrete is not an easy task and its results may be affected by the methodology (Grubb et al, 2007;Alonso et al, 2011;Wan et al, 2013), the obtained pH values can be used to discuss the pH variations that occurred in the concrete specimens as a result of the cycles of carbonation / re-alkalisation / re-carbonation to which they were subjected.…”

Section: Resistance To Re-carbonation [Subheading]mentioning

confidence: 99%

Resistance to carbonation of concrete after re-alkalization by absorption of sodium carbonate solution

Redaelli

Bertolini

2016

Studies in Conservation

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The paper presents experimental research on the durability of a non-conventional technique for the repair of reinforced concrete damaged by carbonation-induced corrosion of steel reinforcement. The technique is called electrochemical re-alkalization and is often considered as an option for the repair of buildings, structures, and other artefacts made of reinforced concrete, for which conservation requirements are becoming increasingly important, in spite of their relatively young age. Absorption of a sodium carbonate solution is one of the processes that lead to concrete re-alkalization. The aim of the work is to investigate the contribution of this process to preventing future carbonation of re-alkalized concrete. Concrete specimens with six different compositions were initially carbonated, then re-alkalized through absorption of a sodium carbonate solution, and then exposed again to carbonation (re-carbonation). The results showed that the pH of concrete after re-carbonation was only slightly lower compared to that of realkalized concrete, highlighting a contribution of the treatment in preventing future pH reduction

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Round Robin Test for Defining an Accurate Protocol to Measure the Pore Fluid pH of Low-pH Cementitious Materials

Cited by 16 publications

References 12 publications

Evaluation of Fillers for Magnesium Potassium Phosphate Cement (MKPC) for the Encapsulation of Low and Intermediate Level Metallic Radioactive Wastes

Evaluation of Fillers for Magnesium Potassium Phosphate Cement (MKPC) for the Encapsulation of Low and Intermediate Level Metallic Radioactive Wastes

New Sensors for Monitoring pH and Corrosion of Embedded Steel in Mortars during Sulfuric Acid Attack

Resistance to carbonation of concrete after re-alkalization by absorption of sodium carbonate solution

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