Caracterización del proceso de descalcificación en morteros, mediante ensayos destructivos y no destructivos
Several applications of concrete need a deffinition of durability and life-cycle extended on time. Some examples of these applications among others, are those used on waste confinement (as those produced on solid urban residues incineration plants or those derived from nuclear combustible), pipes, w...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2008 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/7610 |
| Acceso en línea: | http://hdl.handle.net/10261/7610 |
| Access Level: | acceso abierto |
| Palabra clave: | Caracterización Cementos Descalcificación Durabilidad Microestructura Modelización Mortero Velocidad ultrasónica |
| Sumario: | Several applications of concrete need a deffinition of durability and life-cycle extended on time. Some examples of these applications among others, are those used on waste confinement (as those produced on solid urban residues incineration plants or those derived from nuclear combustible), pipes, water storage tanks and dams. The main degradation process that can affect this structures is caused by natural waters. Water-based degradation processes cause decalcification of the cement-matrix and can lead to a mechanical failure of the structure, caused by the increase on materials porosity and the loss of mechanical properties. Decalcification process in cement mortars has been characterised in this thesis by means of destructive and non-destructive testing. The main aim of this work is to develop a life-cyle estimation model for cement-based materials under decalcification process. To achieve this objective several mortar samples have been made, with different cement types and different water/cement ratios. Samples have been degradated in an accelerated way by inmersion under ammonium nitrate. Microstructural characterization of degraded and non-degraded samples has been tackled by the combination of destructive characterization techniques (thermal analysis, X-ray diffraction, porosity measurements, among others) with non-destructive characterization techniques by means of ultrasonic pulse velocity measurements under water. The models developed in this thesis take in account the CaO content in the cement (accounting for all the components of the cement) and the porosity of non-degraded samples, to estimate the kinetics of the degradation process and the degradation degree of the samples. This model estimates the kinetic parameter from the degraded depth propagation and the ultrasonic velocity in the degradaded zone. Thereby it has been obtained a kinetic model and a cualtitative model for the degradation process. First one allows life-time estimations for materials under decalcification processes. The second one allows to estimate degradation degree and degraded depth from non-destructive ultrasonic measurements. |
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