Microstructure and mineral composition of Roman cements produced at defined calcination conditions

Weber, Johannes; Gadermayr, N.; Kozłowski, Roman; Mucha, Dariusz; Hughes, David; Jaglin, D.; Schwarz, W.

doi:10.1016/j.matchar.2007.04.025

Cited by 42 publications

(29 citation statements)

References 2 publications

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“…Belite grains can be identified based on the typical ‘grape‐shaped’ arrangement of rounded colorless C 2 S crystals with yellowish to brown interstitial phases grown between them . In historical Roman cements, belite occurs in the two structural modifications α ′‐C 2 S and β ‐C 2 S, with an increasing proportion of the latter with higher (super‐optimal) calcination temperatures . In the course of the EU‐funded project ROCEM, Roman cement clinker relicts were classified into three major groups: (1) overfired lumps are characterized by relatively coarse and therefore nonreactive euhedral crystals of belite C 2 S, wollastonite CS, and gehlenite C 2 AS and show local melting.…”

Section: Resultsmentioning

confidence: 99%

“…The second type of this class is fully hydrated but more dense and brittle than the surrounding cement matrix. (3) The third category of underfired phenograins exhibits the structure of the raw material (marlstone), contains widely unaffected quartz and occasionally fossil structures . These criteria allow a more detailed classification of the clinker remnants found in our samples.…”

Section: Resultsmentioning

confidence: 99%

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Determination and imaging of binder remnants and aggregates in historic cement stone by Raman microscopy

Schmid

Dariz

2013

J Raman Spectroscopy

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We present to our knowledge the first application of Raman microscopic imaging to cementitious materials. This technique yielded the composition and phase distribution (spatial resolution % 500 nm) in samples of cement stone taken from façade elements of four Swiss buildings covering the period of 1892-1924. Raman maps of Roman cement, a predecessor of modern Portland cement, reveal the chemical heterogeneity of clinker remnants consisting of various crystalline, polymorphic, and amorphous phases and visualize different crystal orientations. Our findings include the observation of the g-polymorph of Ca 2 SiO 4 -previously, only detected in Portland cement -and Raman spectra of calcium aluminate (ferrite) interstitial phases in Roman cement showing significant differences to the corresponding phases in Portland cement clinker. Furthermore, calcite, vaterite, gypsum, and ettringite were identified in the rim of a nonhydrated residual nodule. Beyond binder remnants, aggregates in the form of spherical (≤500 mm diameter) slag and irregularly shaped pigment particles were analyzed. Here, we focused on the unambiguous identification of compounds in complex matrices by comparing sample spectra with database and own reference spectra. A Raman map collected on blast furnace slag in cement stone shows the spatial distribution of calcite, quartz glass and pyrite. Furthermore, several Fe-containing, Si-containing, and Pb-containing phases were identified. The analysis of pigments partly confirmed and partly contradicted the bequeathed historic recipe of a cement stone façade. These results have direct implications in the field of conservation and restoration and generally demonstrate the potential of Raman imaging to provide deeper understanding of (historic) building materials.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Determination and imaging of binder remnants and aggregates in historic cement stone by Raman microscopy

Schmid

Dariz

2013

J Raman Spectroscopy

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“…The best analysis technique for identifying Roman cement is to use thin-section petrography and support this with electron microscopy to establish the morphological features and chemical composition of unhydrated cement grains; a description of these may be found elsewhere. 19 Data obtained in the latter analysis can then be used to calculate the hydraulic index and cementation index of the unhydrated cement. A review of various analytical techniques has recently been published by Varas et al and applied to Spanish natural cements of the nineteenth century.…”

Section: Materials Analysis and Microstructural Decaysmentioning

confidence: 99%

Roman Cement

Hughes¹,

Swann²,

Gardner³

2007

Journal of Architectural Conservation

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Roman cement had a short period of significant use in comparison to lime and Portland cement. Despite this, there is a legacy of fine buildings about which conservators need to be informed. Part One of this paper (published March 2007) provided a brief history of the material, its characteristics and the mortars used for stucco and cast decorative elements, with due recognition given to the surface finishes which were required. In this paper, a conservation strategy is proposed which includes reference to the EUfunded ROCEM project through which small-scale production of Roman cement has been recommenced. It is determined that further research is required before the impact on the consolidation of the historic fabric from the use of silicate paints can be fully understood.

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“…This is caused not only by their needed use in the restoration of historical monuments (3)(4)(5)(6)(7)(8)(9)(10), but also due to their lower environmental impact during their production and use compared to OPC (11). Natural hydraulic lime (NHL) and/or natural cement (NC) are often required in restoration practice due to their favourable composition (12,13) and physical properties (14) that make them more compatible with traditional construction materials (e.g. natural stone) than is OPC (15).…”

Section: Introductionmentioning

confidence: 99%

Devonian micritic limestones used in the historic production of Prague hydraulic lime (‘pasta di Praga’): characterization of the raw material and experimental laboratory burning

Kozlovcev¹,

Přikryl²

2015

Mater. construcc.

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ABSTRACT:The Devonian micritic limestones from the Prague Basin (Barrandian area, Bohemian Massif, Czech Republic), which were the primary raw material used for natural hydraulic lime burned in Prague, exhibit a feebly to eminently hydraulic character. Based on a laboratory experimental study, the burned product is composed of dominant free-lime (CaO) and/or portlandite (Ca(OH) 2 ), larnite-belite (bicalcium silicate 2CaO.SiO 2 ), and quartz (SiO 2 ) -i.e. phases formed due to the decomposition of carbonate and quartz, present in the original limestones. Proportions of the newly formed phases depend on: the composition of the raw material, maximum burning temperature (the highest amount of larnite-belite appearing at a burning temperature of 1200 °C), and the granulometry of the experimental batches (a coarsely-ground batch exhibited a higher amount of larnitebelite compared to the finely-ground one). The presence of minor phyllosilicates in the raw material contributed to the formation of gehlenite, brownmillerite, wollastonite, calcium aluminate, and/or spurrite. RESUMEN: Calizas micríticas devonianas utilizadas en históricamente en la producción de la cal hidráulica de Praga ('pasta di Praga'): caracterización de las materias primas y procedimiento experimental de calcinación en laboratorio.Las calizas micríticas devonianas provenientes de la Cuenca de Praga (área de Barrand, macizo de Bohemia, República checa) que fueron la principal materia prima utilizada para la producción de la cal hidráu-lica natural calcinada en Praga, presentan un carácter hidráulico desde débil hasta alto. El estudio experimental de laboratorio, ha determinado que el producto calcinado está compuesto de cal viva (CaO) como componente predominante y/o cal hidratada (Ca(OH) 2 ), larnita-belita (silicato bicálcico 2CaO.SiO 2 ) y cuarzo (SiO 2 ) -es decir, fases formadas como resultado de la descomposición de carbonato y cuarzo presentes en las calizas originales. Las proporciones de las nuevas fases formadas dependen de: la composición de la materia prima, temperatura máxima de calcinación (la mayor cantidad de larnita-belita se produce a la temperatura de calcinación de 1200 °C), y la granulometría de las muestras (las muestras con granulometría gruesa presentaron mayor cantidad de belita que las de granulometría fina). La presencia de bajas cantidades de filosilicatos en la materia prima contribuyó a la formación de gehlenita, brownmillerita, wollastonita, calcio aluminoso, y/o spurrita.

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Microstructure and mineral composition of Roman cements produced at defined calcination conditions

Cited by 42 publications

References 2 publications

Determination and imaging of binder remnants and aggregates in historic cement stone by Raman microscopy

Determination and imaging of binder remnants and aggregates in historic cement stone by Raman microscopy

Roman Cement

Devonian micritic limestones used in the historic production of Prague hydraulic lime (‘pasta di Praga’): characterization of the raw material and experimental laboratory burning

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