Co-precipitation of ettringite of rapid and slow formation. Consequence: Expansive Synergic Effect. Its demonstration by mortars and concretes
[EN]Several prior papers have shown that enough pozzolans can bring about rapid formation ettringite (from its Al2O3 r-). It has likewise been found that the formation rate of this ettringite is higher than the of slower forming ettringite originating from OPC (from its C3A). In this context: What t...
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/90144 |
| Acceso en línea: | http://hdl.handle.net/10261/90144 |
| Access Level: | acceso abierto |
| Palabra clave: | Gypsum attack Metakaolin Portland cements Rapid and slow forming ettringites Synergies Ataque del yeso Cementos Pórtland Ettringitas de “rápida” y “lenta” formación Sinergias |
| Sumario: | [EN]Several prior papers have shown that enough pozzolans can bring about rapid formation ettringite (from its Al2O3 r-). It has likewise been found that the formation rate of this ettringite is higher than the of slower forming ettringite originating from OPC (from its C3A). In this context: What type of effect will they ultimately produce? Addition? Synergism? Antagonism? or perhaps Inversion of final expansive action? To reply to these questions, 4 PC and 12 blended cements containing 20%, 30% or 40% metakaolin, were tested using the ASTM C 452-68, EN 196-1 and RT-86:ΔL tests and also concrete specimens. The experimental results have shows that the joint precipitation in a common sulfate medium, of ettringite from pozzolan and from OPC, was always more synergic than additive, and the technical consequences of the Expansive Synergic Effect may be classified as beneficial, adverse or indifferent according to its sulfates content in excess is more or less adequate. |
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