Mineralogical characterization and reactivity test of common clays suitable as supplementary cementitious material

Maier, Matthias; Beuntner, Nancy; Thienel, Karl‐Christian

doi:10.1016/j.clay.2021.105990

Cited by 49 publications

(27 citation statements)

References 54 publications

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“…The calcination temperatures were chosen following previous studies on pozzolanic reactivity. 31,32 The calcined clays were ground for 10 min in a rotary disc mill using an agate grinding tool. Additionally, a nanolimestone (Skyspring Nanomaterials, Inc.), referred to as nLS, which provides high SSA but neither reactive silicon nor aluminum ions, was investigated solely by isothermal calorimetry to examine the pure effect of surface area.…”

Section: Cementitious Model Systemmentioning

confidence: 99%

Hydration of cubic tricalcium aluminate in the presence of calcined clays

et al. 2021

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Calcium sulfates take an important role in the reaction of pozzolanic materials by forming ettringite with aluminum ions from the pozzolan. 1 Sulfate carriers like gypsum, bassanite, or anhydrite are used to retard the tricalcium aluminate (C 3 A) reaction in ordinary portland cement (OPC). 2 The latter mechanism is used to avoid flash set and to optimize strength development by preventing a superposition of the silicate and aluminate clinker reaction. 3 As calcined clay blended cements 4 or limestone calcined clay cements (LC 3 ) 5 are currently among the most promising solutions to address CO 2 emissions in cement industry 6 , their influence on cement hydration in general and on the aluminate reaction in particular is gaining attention. In calcined clay blended cements, where additional aluminum sources are present, awareness has been raised for extra sulfate demand, as the

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Section: Cementitious Model Systemmentioning

confidence: 99%

Hydration of cubic tricalcium aluminate in the presence of calcined clays

et al. 2021

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“…The second product of the pozzolanic reaction, calcite, revealed that its proportion increased in all the mixtures. Paying attention to the development of the chemical balance of the reaction, the generation of calcium carbonate moved towards a higher formation of this specie can be manifested in addition to an amorphous phase, in some of its polymorphic phases as aragonite, when the proportion of carbonate was small and as calcite when the concentration of carbonate was high [ 21 ].…”

Section: Discussion Of Resultsmentioning

confidence: 99%

“…As is known, the exploitation of a low-activity pozzolan when mixed with other high-activity pozzolans will improve its performance, yielding binary, ternary and even quaternary pozzolanic mixtures [ 19 , 20 , 21 ], as is covered in the European regulation on common cements [ 22 ]. Laminated glass that is present in CDW residues, because of its amorphous nature, could constitute a waste stream for recycling as an agent activating pozzolanic mixtures.…”

Section: Introductionmentioning

confidence: 99%

Reactivity of Binary Construction and Demolition Waste Mix as Supplementary Cementitious Materials

et al. 2021

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Calcareous and siliceous CDW wastes from concrete and glass wastes when mixed in binary mixtures has been analyzed in this study. Fine CDW fractions (<5 mm) of different sorts are selected: siliceous waste (HsT), calcareous waste (HcG) and laminated glass waste. The binary mixtures HsT/glass and HcG/glass at mix-proportions of 1:1, 2:1 and 1:2, respectively, are analyzed with a range of characterization techniques (XRD, TG/DTA, SEM-EDX, NMR, FT-IR) in the pure pozzolan/lime system over a reaction time of 90 days. The results showed that the incorporation of highly reactive recycled glass modified the pozzolanic reaction of the binary mixtures with respect to each particular concrete waste (of low activity). The principal mineralogical phases of the reaction were calcite and C–S–H gel, the latter modifying the C/S and A/S ratios as a function of either the silica or the lime-based concrete waste and the glass content of the mixtures. A higher degree of polymerization, morphology, and sodium content of C-H-S gel formed when glass was added.

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“…When limited to one type of SCMs; specifically calcined clays, the kaolinite content controls their reactivity; the heat release measured in the R 3 test increases linearly as the kaolinite content increases [8,27]. Calcined kaolinite systems are substantially more reactive than calcined montmorillonite or illite systems due to their greater disorder and the presence of 5-coordinated aluminum [28].…”

Section: Bulk Chemistry and Amorphous Contentmentioning

confidence: 99%

Recent developments in reactivity testing of supplementary cementitious materials

Suraneni

2021

RILEM Tech Lett

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Identification and rapid characterization of novel supplementary cementitious materials (SCMs) is a critical need, driven by shortfalls in conventional SCMs. In this study, we present a discussion of recently developed reactivity tests – the R3 test, the modified R3 test, the lime strength test, and the bulk resistivity index test. These tests measure reactivity parameters such as heat release, bound water, calcium hydroxide consumption, strength, and bulk resistivity. All tests can screen inert from reactive materials. To additionally differentiate pozzolanic and latent hydraulic materials, two parameters, for example, calcium hydroxide consumption and heat release, are needed. The influences of SCM bulk chemistry, amorphous content, and fineness on measured reactivity are outlined. Reactivity test outputs can predict strength and durability of cement paste/mortar/concrete; however, caution must be exercised as these properties are influenced by a variety of other factors independent of reactivity. Thoughts are provided on using reactivity tests to screen materials for concrete durability.

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Mineralogical characterization and reactivity test of common clays suitable as supplementary cementitious material

Cited by 49 publications

References 54 publications

Hydration of cubic tricalcium aluminate in the presence of calcined clays

Hydration of cubic tricalcium aluminate in the presence of calcined clays

Reactivity of Binary Construction and Demolition Waste Mix as Supplementary Cementitious Materials

Recent developments in reactivity testing of supplementary cementitious materials

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