Browsing by Author "Espinosa, Ana B."
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Item Durability Studies on Fiber-Reinforced Siderurgic Concrete(International Center for Numerical Methods in Engineering, 2020) Ortega-Lópe, Vanesa; Revilla-Cuest, Víctor; Santamaría, Amaia; Espinosa, Ana B.; Fuente-Alonso, José A.; Chica, José A.; Serrat, Carles; Casas, Joan Ramon; Gibert i Armengol, Vicente; SGThe construction sector is clearly one of the most pollutant at a global level and its consumption of natural resources is also enormous. Over recent years, heightened awareness of this issue within the construction sector has motivated changes within its working practice,seeking to reduce its environmental impacts and to mitigate the effects of climate change. The consumption of natural resources can be reduced in very different areas and special attention has been given to the substitution of Natural Aggregates (NA) in concrete design by replacing those aggregates with various waste coproducts. Siderurgic concrete is the name given to concrete manufactured with siderurgical aggregate from the steel-making industry. In this paper, test results on fiber-reinforced siderurgical concrete are reported. The concrete is manufactured with approximately 50% Electric Arc Furnace Slag (EAFS) aggregate by volume, for use in pavement applications. Steel and polypropylene fibers, amounting to approximately 0.5% by volume of the concrete mass, are also added to the mix. The durability properties of this concrete type are analyzed through freeze/thaw and moist/dry tests. Furthermore, the long-term behavior of the concrete is explained through its internal structure, using Mercury Intrusion Porosity (MIP) and low-vacuum Scanning Electron Microscopy (SEM) analyses. The results add further weight to the feasibility of using EAFS in replacement of NA in fiber-reinforced concrete for pavement construction.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.