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Madrid, Spain

Gutierrez Jimenez J.P.,IETCC CSIC | Garcia Alonso M.D.,Technical University of Madrid
Engineering for Progress, Nature and People | Year: 2014

Nowadays there is an increasing need of reusing/recycling existing means. This also occurs in construction field where numerous ageing buildings and infrastructures need to be upgraded. Externally bonded FRP (fiber reinforced polymer) laminates has been proven a useful technique for structural strengthening not only for reinforced concrete structures but for others like masonry ones. An ultimate limit state method to design and check unreinforced masonry sections with externally bonded FRP strengthening subject to bending and compression has been developed.Different design formulations are proposed with the aim of covering all flexural failure modes. The work focuses on determinate a "bond reduction factor" to assess the value of FRP design strain. This factor must prevent intermediate FRP debonding failure. The proposed factor is obtained by means of an extensive bending test database. The method has also been checked with the help of this database. Source

Menendez E.,IETCC CSIC | de Frutos Y.J.,Complutense University of Madrid
Boletin de la Sociedad Espanola de Ceramica y Vidrio | Year: 2012

In this paper, we study how to generate and accelerate, expansive phenomena within cementitious composites, considering elements of addiction using both fly ash and slag. We present results of monitoring of these processes from the beginning and characterize chemical, microstructural, and crystallographic by X-ray diffraction, backscattering electron microscopy, X-ray dispersive energy and mercury porosimetry. These data are supplemented with values of mechanical behavior of materials to determine their functionality. As a result of these studies, we propose a model for the generation and progression of microcracks for each alteration processes studied. Source

Nevshupa R.A.,IETCC CSIC | Conte M.,IK4 Tekniker | Igartua A.,IK4 Tekniker | Roman E.,CSIC - Institute of Materials Science | De Segovia J.L.,CSIC - Institute of Materials Science
Tribology International | Year: 2015

The main difficulty in designing of an ultrahigh vacuum (UHV) tribometer combined with tribophysical and tribochemical characterization techniques is to find the critical compromise between the scientific requirements and technical or technological limitations from different subsystems and components. The principal conflicts, their possible solutions and the recommended tribometer configurations are analyzed. The developed methodological principles were applied for designing and construction of two UHV experimental tribological systems: TriDes-2 and Ca3UHV. The advances in the design and development of the vacuum system as well as the UHV force sensor and sample holder are presented and discussed. © 2015 Elsevier Ltd. All rights reserved. Source

Torrens-Martin D.,Polytechnic University of Catalonia | Fernandez-Carrasco L.,Polytechnic University of Catalonia | Blanco-Varela M.T.,IETCC CSIC
Journal of Thermal Analysis and Calorimetry | Year: 2013

Different binders of Portland cement, calcium aluminate cement and calcium sulphate (PC/CAC/CS) have been investigated to determinate the influence the CAC and CS amount in the reactions mechanism. Several mixtures were studied, ratios of 100, 85/15 and 75/25 of PC/CAC with 0, 3 and 5 % of CS. Conduction calorimetric technique was used to follow the hydration during 100 h. The XRD and FTIR techniques were used as support in the analysis of the hydration products. The results have shown that the studied ternary systems form an extra amount of ettringite, and changes in the reactions mechanism with respect to a PC. The reactions mechanism depends on the CAC and CS amount present in the different binders. © Akadémiai Kiadó, Budapest, Hungary 2013. Source

Nevshupa R.,IETCC CSIC | Conte M.,IK4 Tekniker | Van Rijn C.,Noon Energy S.L.
Measurement Science and Technology | Year: 2013

The measurement uncertainty and linearity of a bundle fibre-optic displacement sensor were studied on a wide range of displacements using experimental and simulation approaches. The theoretical He-Cuomo distribution functions of light intensity yielded the simulated modulation characteristic that best fitted the experimental data in the range of dimensionless distances to the target surface from 0 to 50 but diverged beyond. The coefficient of variation of the output signal of the sensor varied non-monotonically with the distance to the target surface. This variation is suggested to stem from small randomly distributed imperfections on the mirror surface. © 2013 IOP Publishing Ltd. Source

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