Cedex Laboratorio Central Of Estructuras Y Materiales

Madrid, Spain

Cedex Laboratorio Central Of Estructuras Y Materiales

Madrid, Spain

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Blanco M.,Cedex Laboratorio Central Of Estructuras Y Materiales | Castillo F.,Cedex Laboratorio Central Of Estructuras Y Materiales | Touze-Foltz N.,IRSTEA | Amat B.,Firestone Building Products | Aguiar E.,BALTEN
10th International Conference on Geosynthetics, ICG 2014 | Year: 2014

The purpose of this study is to evaluate the durability of an EPDM geomembrane installed 18 years ago in the water reservoir of El Boquerón (Canary Islands, Spain). To do so, samples were regularly taken from different places of the water reservoir. Samples were laboratory tested as follows: foldability at low temperature, static and dynamic puncture resistance, Shore-A hardness, tensile strength and elongation at break, seam strength and microscopic techniques. The obtained results confirm the EPDM geomembrane is still in good condition.


Peggs I.D.,I Corporation International | Gassner F.,Associates Pty. Ltd. | Scheirs J.,Excelplas | Tan D.,Solmax International Asia Pacific SDN. BHD | And 2 more authors.
10th International Conference on Geosynthetics, ICG 2014 | Year: 2014

Susceptibility to stress cracking (SC) is one of the few concerns about the durability of HDPE geomembranes. The occurrence of short quasi-brittle slow crack growth (SCG) cracks, mostly associated with extrusion welds, and extensive rapid crack propagation (RCP) "shattering" cracks has decreased since the mid 1980s, but SC events over the past few years makes us wonder whether there is a resurgence of SC, including types never seen before. Several case histories of SCG and RCP events are presented from around the world. Common to many of them are initiation sites at extrusion welds of repair patches and significant acceleration of SC by cyclic stresses. Guidance for avoidance of SC is provided.


Velasco-Torres A.,Cedex Laboratorio Central Of Estructuras Y Materiales | Alaejos P.,Cedex Laboratorio Central Of Estructuras Y Materiales | Soriano J.,Cedex Laboratorio Central Of Estructuras Y Materiales
Dam Maintenance and Rehabilitation II - Proceedings of the 2nd International Congress on Dam Maintenance and Rehabilitation | Year: 2011

The presence of metaestable silica in some aggregates used in concrete (quartzites, granites, etc) plays an important role in the alkali-silica reaction (ASR). The aggregates are always selected among the rocks near the construction emplacement to avoid a long transport distance, which increases the cost. The geologic maps of Spain provide extremely useful information to detect the presence of reactive aggregates, which could develop an alkali-silica reaction. The petrographic study carried out in aggregates used in different real works shows a close relationship between the geologic information in the maps and the risk to develop ASR pathology, so a "Risk of ASR pathology map" can be established. © 2011 Taylor & Francis Group, London.


Velasco-Torres A.,Cedex Laboratorio Central Of Estructuras Y Materiales | Alaejos P.,Cedex Laboratorio Central Of Estructuras Y Materiales | Soriano J.,Cedex Laboratorio Central Of Estructuras Y Materiales
Estudios Geologicos | Year: 2010

The reaction between certain reactive components of aggregates (like opal and metaestable silica) and concrete pore solution is well documented. Nevertheless, in this study it has been shown that some aggregates, like granite, could develop a rapid or slow alkali-silica reaction (ASR) depending on the deleterious component involved. Mortar bars were cast with two granitic aggregates extracted from concrete cores drilled in two Spanish Dams affected by ASR, being classified as granitic rocks. The main difference between them is the reactive component: microcrystalline quartz in one case and strained and microcracked quartz in the other case. A petrographic examination was carried out in the mortar bars. Thin sections were cut and the alkalisilica gel was stained for an easier detection. Then, the thin sections were examinated with a stereomicroscope comparing the differences in the progress of the ASR for both aggregates. It can be concluded that the main mechanism of formation and storage of gel is associated to the microcracks instead of the subgrain boundaries.

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