Browsing by Author "Revilla-Cuesta, Víctor"
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Item Bending tests on building beams containing electric arc furnace slag and alternative binders and manufactured with energy-saving placement techniques(2021-08) Santamaría, Amaia; García-Llona, Aratz; Revilla-Cuesta, Víctor; Piñero, Ignacio; Ortega-López, Vanesa; E&I SEGURAS Y RESILIENTESThe environmental impact of the building sector is especially relevant during the construction phase. Both the materials and the construction methods that are currently in use must be reconsidered, in order to minimize the environmental impact of concrete-based structures. This research is therefore focused on achieving greener concrete-based building structures. In this context, the feasibility of careful use of materials for concrete manufacture and the use of construction techniques that can facilitate and reduce energy consumption during placement are both studied. To do so, twelve sample beams were prepared using eight different sustainable high-workability structural concretes. The aim was to maximize the use of the by-products that amounted to over 80% of the concrete mass, steelmaking slags, fly ash, and quarry waste, and to employ energy-saving concrete placement techniques. The beams underwent bending tests in which their mechanical behavior and their compliance with the specifications of the most relevant building codes were verified. The results pointed to the feasibility of increased sustainability in the field of building engineering through the suitable use of selected by-products and techniques.Item Quantification and characterization of the microstructural damage of recycled aggregate self-compacting concrete under cyclic temperature changes(2023-02-15) Revilla-Cuesta, Víctor; Skaf, Marta; Chica, José A.; Ortega-López, Vanesa; Manso, Juan M.; SGRecycled Aggregate (RA) usually increases porosity and weakens Interfacial Transition Zones (ITZs) of concrete, which favors the appearance of internal thermal damage. Four Self-Compacting Concrete (SCC) mixes with coarse and fine RA were subjected to positive and negative cyclic temperature variations to characterize their thermal damage and quantify its effects. Two damage mechanisms were found. On the one hand, micro-cracks appeared in the ITZs. On the other hand, micro-cracks arose from the micro-pores and propagated through the cementitious matrix. Both damage mechanisms were promoted by the use of coarse and fine RA, respectively. The damage was most notable at sub-zero temperatures and when adding coarse RA. Furthermore, it primarily affected compressive strength, although ultrasonic pulse velocity and hardened density also decreased, which served as non-destructive indicators to indirectly quantify the level of thermal internal damage of SCC.Item Recycled Self-Compacting Concrete: Mechanical Behavior and Durability(American Concrete Institute, 2022-07-01) Revilla-Cuesta, Víctor; Skaf, Marta; Chica, José A.; Serrano-López, Roberto; Ortega-López, Vanesa; Coffetti, Denny; Coppola, Luigi; Holland, Terence; SGIncreasing sustainability is currently one of the main objectives of the construction sector. One of the most widespread sustainable practices to reach this goal is the recycling of industrial residues within concrete mixes. What began as a practice to produce low-quality concrete has now spread, for example, to Self-Compacting Concrete (SCC), which has a high flowability in the fresh state. Recycled Concrete Aggregate (RCA) is a waste that can be used to develop SCC of good mechanical performance. RCA produced from the crushing of rejected precast components for the prefabricated concrete industry is assessed in this study. It was demonstrated that the addition of 100 % coarse RCA and 50 % fine RCA contributed to the production of an SCC with adequate flowability and an optimal mechanical and durability behavior. To do so, the design of the mixture, its flowability, its strength behavior at different curing ages and its performance in freeze/thaw, moist/dry and sulfate-attack tests are discussed. The study is complemented by analyzing the interaction of RCA with different natural fine aggregates, such as siliceous or limestone sand. It is concluded that the SCC developed with large amounts of RCA was of sufficient strength and durability for general usage.Item Thermal deformability of recycled self-compacting concrete under cyclical temperature variations(2020-11-01) Revilla-Cuesta, Víctor; Skaf, Marta; Chica, José Antonio; Fuente-Alonso, José Antonio; Ortega-López, Vanesa; SGRecycled Concrete Aggregate (RCA) has greater elasticity than natural aggregate, due to the presence of adhered hydrated mortar in the coarse fraction, and mortar particles in the fine fraction. To evaluate this aspect under temperature variations, four Self-Compacting Concretes (SCC) made with 100% coarse and/or fine RCA were subjected to cyclical temperature variations between 70 °C and 20 °C and between −15 °C and 20 °C. The addition of RCA, especially in the coarse fraction, increased the thermal deformability, although the difference tended to decrease with the number of cycles, especially in positive temperature variations. This study concludes that the traditional upper limit of the linear thermal expansion coefficient for concrete (1.2·10−5 °C−1) is also suitable when RCA is incorporated.Item VALIDATION OF ULTRASONIC PULSE TO QUALITY CONTROL OF RECYCLED AGGREGATE SELF-COMPACTING CONCRETE(University of Cantabria - Building Technology R&D Group, 2022) Revilla-Cuesta, Víctor; Santamaría, Amaia; Espinosa, Ana B.; Chica, José A.; Manso, Juan M.; Ortega-López, Vanesa; Blanco, Haydee; Boffill, Yosbel; Lombillo, Ignacio; SGOne of the main operations in any civil work is to verify that the concrete supplied and placed on site reaches the required minimum compressive strength. This verification is usually performed statistically through the preparation and testing of a large number of specimens. However, its indirect control is also useful due to its simplicity, ease of execution, and low cost. One of the most common methods to perform this operation is the measurement of the Ultrasonic Pulse Velocity (UPV) of the cast concrete, checking that its value corresponds to the necessary concrete’s strength class. This study aims to analyze whether this indirect measurement, widely used in vibrated concrete produced with natural aggregate, is also valid when large quantities of Recycled Concrete Aggregate (RCA) are added to Self-Compacting Concrete (SCC). For this purpose, six SCC mixes were produced with 100% coarse RCA and variable fine RCA contents (0%, 50%, and 100%). In addition, two different types of powder were used: Limestone filler <0.063 mm and limestone fines 0/0.5 mm. The determination of the compressive strength and the UPV at 7 and 28 days in all mixes allowed demonstrating the existence of a close relationship between these two magnitudes in this type of concrete. It was even possible to develop highly accurate simple-regression models to interrelate both variables. These findings show that the use of SCC with RCA in engineering works would still allow the control of compressive strength using one of the most common traditional techniques, the ultrasonic pulse.