Low-grade RC beams strengthened with TRM composite based on basalt, carbon and steel textiles: Experimental and analytical study

IDI-20101594 IDI-20101592 MCIN/AEI/10.13039/501100011033/ FEDER, UE [PID2021–124203OB-I00 and RTI2018–097079-B-C31] IT1619–22This study develops an easy-to-conduct numerical calculation method to assess the effect of Textile Reinforced Mortar when used as externally bonded flexural strengthening technique in low-grade reinforced concrete beams from ancient structures (aged between 60 and 100 years old). Using materials main mechanical characteristics and the beams dimensions as inputs, the model defines the behaviour of the strengthened elements. This paper includes the experimental characterization of the whole strengthening solution, from the constituent materials and the composite in pure tensile to scaled beams strengthened in flexure. In total three different materials – basalt, carbon and steel cords – are used as Textile Reinforced Mortar inner reinforcement. Tests are carried out on sixteen low-grade reinforced concrete beams that reproduce low-quality concretes with a compression strength below 17 MPa and, in general, poor mechanical properties, as those present in old and decayed structures. This experimental campaign includes the study of two other particular features of the adopted retrofitting technique: the strengthening ratio and the use of an anchorage system. The obtained experimental findings are assessed and satisfactorily compared with the developed numerical approach, leading us to conclude that Textile Reinforced Mortar is an effective solution for retrofitting structures made of low-grade reinforced concretes in terms of increasing their deformation and load-bearing capacity under flexural loads (the maximum bending moment has increased between 30% and 200%). Besides, the failure mechanism due to undesired premature detachment was effectively countered using U-shaped anchors, failing the strengthened beams due to the composite tensile failure.publishersversionpublishe

Global study of the behaviour of textile reinforced mortar under tensile stress

The authors would like to thanks the Fundación Iñaki Goenaga for its scholarship programme and the financial support of the regional Diputación Foral de Bizkaia (Birgaitek, DFB-7/12/TK/2009/10).publishersversionpublishe

Evaluation of the theoretical, technical and economic potential of industrial waste heat recovery in the Basque Country

Industrial waste heat recovery shows significant potential for increasing energy efficiency in industry. However, to design strategies that exploit this potential, it is necessary to have data about the quantity and characteristics of industrial waste heat flows. This information is not always readily available and many companies do not even have a systematic record of these energy flows. Hence, bottom-up methodologies to estimate that recovery potential by means of key transfer figures are useful tools within this field. In the present article, four different methods are applied to determine the industrial waste heat recovery potential in the Autonomous Community of the Basque Country (northern Spain), an energy-intensive industrial region with large energy dependency from the outside. Besides, the analysis of the economic viability of the industrial waste heat recovery is essential, because it determines the final adoption of energy efficiency measures. For that aim, the authors develop an easy-to-apply bottom-up methodology to carry out an assessment for the economic potential of the estimated industrial waste heat at different temperature levels. This method is applied to 129 companies, whose potentials are characterized and discussed. The obtained results show that, for waste heat streams above 400 ?C, more than 90% of the studied companies present payback periods below five years. For those industries with waste heat temperatures below 200 ?C, the ratio decreases to around 40%, still a noticeable value. The estimations show a significant opportunity to implement solutions to recover this wasted energy, especially in the iron and steel sector and the petrochemical industry. The development of public policies that encourage these measurements would be also beneficial.The authors would like to acknowledge the Spanish Ministry of Science and Innovation (MICINN) for funding through the SweetTES research project (RTI 2018099557BC22)

Mortar-based systems for externally bonded strengthening of masonry

Mortar-based composite materials appear particularly promising for use as externally bonded reinforcement (EBR) systems for masonry structures. Nevertheless, their mechanical performance, which may significantly differ from that of Fibre Reinforced Polymers, is still far from being fully investigated. Furthermore, standardized and reliable testing procedures have not been defined yet. The present paper provides an insight on experimental-related issues arising from campaigns on mortar-based EBRs carried out by laboratories in Italy, Portugal and Spain. The performance of three reinforcement systems made out of steel, carbon and basalt textiles embedded in inorganic matrices has been investigated by means of uniaxial tensile coupon testing and bond tests on brick and stone substrates. The experimental results contribute to the existing knowledge regarding the structural behaviour of mortar-based EBRs against tension and shear bond stress, and to the development of reliable test procedures aiming at their homogenization/standardization

Flexural strengthening of low-grade reinforced concrete beams with compatible composite material: Steel Reinforced Grout (SRG)

Publisher Copyright: © 2019 Elsevier LtdA substantial fraction of the existing housing stock is built with low-quality reinforced concrete that shows poor mechanical properties. Those concretes, labelled low-grade concretes, present certain drawbacks when common strengthening techniques are used for their rehabilitation. Over recent decades, a number of investigations have added to our knowledge of strengthening materials in the form of inorganic-based composites. Amongst those materials, Steel Reinforced Grout (SRG) presents optimum characteristics for flexural strengthening in situations where the use of other retrofitting techniques is not recommendable. Previous applications of SRG include the reinforcement of constructive components that include masonry walls, arches, and even slabs, in positions where the adherence of externally bonded organic composites such as FRP can present difficulties. The adherence of organic binders is not appropriate for low-performance concrete substrates and can cause FRP laminate debonding and the detachment of the concrete substrate. The central theme of this study is the strengthening of low-performance RC beams with SRG to resist flexural forces. This innovative material forms a cement-based matrix, rather than an organic binder, which is a partial solution for the above-mentioned lack of full compatibility between ancient concrete and externally bonded strengthening solutions. In addition, SRG presents additional advantages such as: fire resistance, durability, and some reversibility. Tests are performed on eighteen reinforced concrete (RC) beams (17 MPa): two reference specimens and sixteen specimens to study particular aspects of the SRG strengthening solution: the strengthening ratio and the performance of two anchorage systems. The results achieved in this research work lead us to conclude that SRG is an effective solution for the retrofitting of low-grade reinforced concrete to increase its load-flexural and deformation capacity.The authors wish to express their gratitude for funding through the Basque Government (ADVICE project - Emaitek 2015 - contract 049639), CDTI (Spanish Ministry MICINN - TERREME project - contracts IDI-20101592 and IDI-20101594), the Spanish Government (DESCLIMA project - contract RTI2018-097079-B-C31 - MCIU/AEI/FEDER, UE), as well as UPV/EHU (contract PPGA19/61), and finally, our thanks to research groups: IT1314-19 (Basque Government) and GIU19/029 (UPV/EHU). The authors wish to express their gratitude for funding through the Basque Government (ADVICE project - Emaitek 2015 - contract 049639), CDTI (Spanish Ministry MICINN - TERREME project - contracts IDI-20101592  and IDI-20101594), the Spanish Government (DESCLIMA project - contract RTI2018-097079-B-C31 - MCIU/AEI/FEDER, UE), as well as UPV/EHU (contract PPGA19/61), and finally, our thanks to research groups: IT1314-19 (Basque Government) and GIU19/029 (UPV/EHU).Peer reviewe

Textile-reinforced mortar as strengthening material for masonry arches

[EN] Masonry arches are an important part of built heritage that must be preserved. Research and advanced studies of historical masonry structures have progressed slowly in comparison to studies on structures made of other materials (e.g., concrete, steel), resulting in a lack of knowledge and experience in this field. This research evaluates the effectiveness of basalt textile-reinforced mortar (BTRM) as a compatible strengthening composite material for stone masonry arches, providing researchers with further quantitative data. To do so, 11 masonry arches were constructed, strengthened with different layouts, and tested. Furthermore, the BTRM was characterized by testing its constituent materials and the composite material. Once analyzed and compared with other studies, the results showed that BTRM is a promising solution for strengthening stone masonry arches. It is easy to apply, compatible and gives the original structures greater mechanical properties, in terms of ultimate load and deformation capacity.[ES] Los arcos de mampostería son una parte importante del patrimonio construido que debe preservarse. La investigación y los estudios avanzados de estructuras históricas de mampostería han avanzado lentamente en comparación con los estudios sobre estructuras hechas de otros materiales (por ejemplo, hormigón, acero), lo que ha resultado en una falta de conocimiento y experiencia en este campo. Esta investigación evalúa la eficacia del mortero reforzado con tejidos de basalto (BTRM) como material compuesto de refuerzo compatible para arcos de mampostería de piedra, proporcionando a los investigadores más datos cuantitativos. Para ello se construyeron 11 arcos de mampostería, se reforzaron con diferentes disposiciones y se probaron. Además, el BTRM se caracterizó por ensayar sus materiales constituyentes y el material compuesto. Una vez analizados y comparados con otros estudios, los resultados mostraron que BTRM es una solución prometedora para fortalecer los arcos de mampostería de piedra. Es de fácil aplicación, compatible y confiere a las estructuras originales mayores propiedades mecánicas, en términos de carga última y capacidad de deformación.Este trabajo de investigación ha sido posible gracias a la financiación del Gobierno Vasco (TEXMOR-S-PE07LA09) y la Diputación Foral de Bizkaia (BIRGAITEK 7-12-TK-2009-10)

Innovative strengthening solution based on Textile Reinforced Mortar for stone masonry arches

This paper aims to present the design, strengthening and testing of full scale masonry walls and arches. The preservation of our cultural heritage is a really important topic. Majority of masonry structures are deteriorated because of ageing effects, load increments, movements at their foundations, etc. Because of this, retrofitting is needed. In order to afford this problem, a compatible and minimally invasive strengthening technique based on Textile Reinforced Mortar (TRM) is developed. The experimental campaign consists of the characterisation of the constitutive materials of the stone structures and the strengthening textile and mortar (TRM has been characterised by pure tensile tests). Furthermore, the influence of the different arrangements of the masonry and mortar type has been analysed by testing 24 masonry prisms. Finally, 12 full-scale stone arches have been erected, strengthened and tested. The purpose is to compare the mechanical behaviour up to failure of both unstrengthened and strengthened structures. During the tests the effectiveness of the technique has been proved being the ultimate load up to 21 times higher.Peer reviewe

Industrial waste heat district-heating design based on geographic information system: Case study in vitoria-gasteiz (Spain)

Publisher Copyright: © Content from this work may be used under the terms of the Creative Commons Attribution 3.0 Licence.The use of georeferenced information system and Light Detection and Ranging (LiDAR) data in combination with traditional data analytics tools is very promising in urban scale engineering and especially in energy urban planning. This paper explores the use of new DH networks for industrial waste heat exploitation and for that purpose, a case-study in Vitoria-Gasteiz (Spain) is proposed. The methodology explained in this paper explores the incorporation of data from industrial emplacements, buildings and road network in order to identify optimal areas in the city for the construction of a new district-heating network. An area of influence of a buffer of radius 1.5km from the industry location is defined and the proposed algorithm divides this area into grids of different sizes. The path for the network is calculated by optimizing the economic performance of the network. The results show that the district-heating may be built in the south-west direction from the industry and among the 40 configurations studied, payback periods from 6 to 8.5 years are obtained.Peer reviewe

Refuerzo de bóvedas de fábrica de ladrillo con materiales compuestos de matriz inorgánica

Peer reviewe

Non-linear analytical model of composites based on basalt textile reinforced mortar under uniaxial tension

[EN] The recent development of inorganic based composites as low-cost materials in reinforced concrete structural strengthening and precast thin-walled components, requires the creation of models that predict the mechanical behaviour of these materials. Textile Reinforced Mortar (TRM) shows complex stress-strain behaviour in tension derived from the heterogeneity of its constituent materials. This complexity is mainly caused by the formation of several cracks in the inorganic matrix. The multiple cracking leads to a decrease in structural stiffness. Due to the severe conditions of the serviceability limit state in structural elements, the prediction of the stress-strain curve is essential for design and calculation purposes. After checking other models, an empirical nonlinear approach, which is based on the crack control expression included in the Eurocode 2, is proposed in this paper. Following this scope, this paper presents an experimental campaign focused on 31 TRM specimens reinforced with four different reinforcing ratios. The results are analysed and satisfactorily contrasted with the presented non-linear approach.[ES] El reciente desarrollo de materiales compuestos de base inorgánica como materiales de bajo coste en el refuerzo estructural de hormigón armado y componentes prefabricados de paredes delgadas, requiere la creación de modelos que predigan el comportamiento mecánico de estos materiales. El Mortero Reforzado con Tejidos (TRM por sus siglas en inglés) muestra un complejo comportamiento tensión-deformación en tensión derivado de la heterogeneidad de sus materiales constituyentes. Esta complejidad se debe principalmente a la formación de varias grietas en la matriz inorgánica. Las múltiples fisuras provocan una disminución de la rigidez estructural. Debido a las severas condiciones del estado límite de servicio en elementos estructurales, la predicción de la curva tensión-deformación es esencial para propósitos de diseño y cálculo. Después de comprobar otros modelos, en este artículo se propone un enfoque empírico no lineal, que se basa en la expresión de control de fisuras incluida en el Eurocódigo 2. Siguiendo este alcance, este artículo presenta una campaña experimental centrada en 31 probetas de TRM reforzadas con cuatro relaciones de refuerzo diferentes. Los resultados se analizan y contrastan satisfactoriamente con el enfoque no lineal presentado.Este trabajo de investigación fue financiado a través del proyecto de investigación DFB 7-12-TK-2009-10 y BIA2010-20789-C04-03/04; y el programa de becas de la Fundación Centros Tecnológicos-Iñaki Goenaga