Person:
Espuelas Zuazu, Sandra

person.page.identifierURI

https://academica-e.unavarra.es/handle/2454/48978

Last Name

Espuelas Zuazu

First Name

Sandra

person.page.departamento

Ingeniería

ORCID

0000-0003-1223-515X

person.page.upna

811351

Full item page

Search Results

Now showing 1 - 10 of 14

Open Access
Magnesium oxide as alternative binder for unﬁred clay bricks manufacturing
(Elsevier, 2017) Espuelas Zuazu, Sandra; Omer, Joshua; Marcelino Sádaba, Sara; Echeverria Lazcano, Angel María; Seco Meneses, Andrés; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Replacement of ﬁred bricks by unﬁred ones could be an eﬀective way to reduce the building industryenvironmental footprint: Their manufacture not only requires less energy and natural resources but alsogenerates less waste. Bricks are based on the use of an additive cementitious material in the form of a binder,usually lime or cement. Such additives have a great environmental impact owing to the high energy consumptionand CO2during in their manufacturing process. In this article experiments are carried out in order to investigatethe applicability of a MgO rich industry by-product as a binder for the production of unﬁred clay bricks. Fromthe experiments, the MgO was observed to show ability to enhance the mechanical properties of a clay brick inmuch the same way as lime does. Water absorption tests on bricks revealed the superiority of MgO over lime inenhancing the durability properties of unﬁred bricks. The laboratory results demonstrate the high potential ofMgO based additives as alternative binders to the calcium based ones. Consequently, this oﬀers opportunity forreducing the environmental impact associated with the use of ﬁred clay bricks. In addition, it could allow aneﬀective way for the valorization of MgO containing industry by-products that currently discarded to landﬁlls
Open Access
Valorización de residuos orgánicos como nuevos combustibles sólidos de biomasa
(2023) Espuelas Zuazu, Sandra; Seco Meneses, Andrés; Marcelino Sádaba, Sara; Ingeniería; Ingeniaritza
Esta tesis se ha centrado en la valorización de dos residuos industriales, que en la actualidad no tienen vías de valorización efectivas, como combustibles sólidos de biomasa para la generación de energía limpia. Con el objetivo de valorizar estos residuos, se ha desarrollado una metodología estructurada en seis fases que permite estudiar el residuo y sus diferentes vías de valorización, además de detectar los posibles residuos que se generen tras el propio proceso de valorización. En primer lugar, se ha valorizado el residuo de marro de café (SCG), mediante la fabricación de briquetas mediante condiciones de baja energía y baja temperatura, formadas con SCG y como ligantes, goma xantana y goma guar. Las briquetas se fabricaron a temperatura ambiente, a 10%, 15%, 20%, 25% y 30% de humedad, con 8, 10 y 12 MPa de presión de compactación y con 5 y 10% de dosis de cada ligante. Se realizaron diversos ensayos para caracterizar las briquetas, en primer lugar, para determinar la capacidad de fabricar briquetas funcionales, se realizaron ensayos de densidad seca, durabilidad y absorción de agua. Por último, se realizaron ensayos químicos para determinar su potencial como combustibles sólidos: análisis elemental, análisis inmediato y ensayo de combustión. La combinación de 10% de xantana, 15% de humedad y a 12 MPa, alcanzó la mayor densidad seca, 0,819 g/cm3 . La combinación de 5% de xantana, 30% de humedad, compactada a 12 MPa fue la más duradera con una pérdida de masa del 3,9%. No se establecieron relaciones entre la absorción de agua y el tipo de ligante, la dosis de ligante, la humedad de fabricación o la presión de compactación. El valor más bajo de absorción de agua, 0,25%, correspondió a la combinación con 5% de xantana, 30% de humedad y compactada a 10 MPa. El poder calorífico inferior alcanzado por el SCG fue de 25,399 MJ/kg. El uso de ligantes disminuyó el poder calorífico, redujo los volátiles, aumentó el contenido de carbono fijado y disminuyó el contenido de nitrógeno. La goma guar disminuyó el contenido de nitrógeno del SCG en un 15,92% para la dosis del 5% y en un 16,92% para las combinaciones con 10%, respectivamente. La reducción de nitrógeno con la goma xantana alcanzó el 13,43% para el 5% y un 14,43% para el 10% de dosificación. La producción de cenizas de SCG fue del 0,66%. Este valor aumentó a 0,81% y 0,97% con el 5% y el 10% de goma xantana, mientras que la goma guar lo redujo al 0,57% y al 0,52%, con el 5% y el 10% de dosificación. El segundo residuo estudiado es el polvo de aislante de celulosa (CFP). Este residuo carece de método de valorización efectivo debido a su contenido en sales de boro. En este caso, se valorizó mediante la fabricación de pellets con lignosulfonato y residuo de la producción de azúcar. Se realizaron diversos ensayos para caracterizar los pellets, en primer lugar, para determinar la capacidad de fabricar pellets funcionales, se realizaron ensayos de densidad seca, durabilidad y absorción de agua. Estos ensayos permiten estimar su comportamiento ante el manejo, transporte y alimentación de las calderas. Además, se realizaron ensayos químicos para determinar su potencial como combustibles sólidos: análisis elemental, análisis inmediato y ensayo de combustión. Por último, se caracterizaron las cenizas obtenidas tras la combustión de los diferentes pellets fabricados. El CFP mostró una buena capacidad de peletización y durabilidad en el rango de 15-30% de contenido de agua. La densidad del pellet disminuyó al aumentar el contenido de agua. Los ligantes aumentaron la longitud del pellet antes y después de la prueba de durabilidad y aumentaron la absorción de agua del pellet, lo que demuestra una posible disminución de la durabilidad frente a los factores ambientales. Los ligantes también disminuyeron el valor calorífico inferior. El análisis elemental mostró un ligero aumento de nitrógeno en las combinaciones con ligantes que podría aumentar las emisiones contaminantes de NOx en la combustión. Todas las combinaciones mostraron unas características de combustión adecuadas, pero los ligantes aumentaron la producción de cenizas. Los ligantes disminuyeron el contenido de volátiles y aumentaron el carbono fijado, lo que podría facilitar una combustión más estable. Las curvas DTA mostraron una disminución de la tasa de pérdida de masa en la fase volátil en el caso de las combinaciones con ligantes, lo que también podría considerarse como un indicador de una combustión más estable. Las composiciones químicas de las cenizas al ser analizadas por XPS mostraron contenidos de boro que oscilaban entre el 10,03% y el 16,42%, demostrando la posibilidad de recuperarlos de las cenizas de combustión.
Open Access
Characterization of fresh and cured properties of polymer concretes based on two metallurgical wastes
(MDPI, 2020) Seco Meneses, Andrés; Echeverria Lazcano, Angel María; Marcelino Sádaba, Sara; García, Beñat; Espuelas Zuazu, Sandra; Institute of Smart Cities - ISC
Polyester polymer concretes can substitute conventional concretes based on their usually good mechanical strength, adequate physical properties, and high resistance against aggressive chemical environments. They also show a high potential for using recycled targets in their manufacturing. This paper analyzes the fresh and cured properties of polyester polymer concretes containing two metallurgical wastes, namely: ladle slag and alumina filler. Both targets require a higher resin dosage than sand. The standard consistency test showed a low representativeness of the recycled fresh mixes’ workability. The ladle slag and alumina filler samples showed a higher length plastic shrinkage than those containing sand. All of the targets obtained cured density values in the range of 1.589–1.912 g/cm3. From a mechanical point of view, the sand and alumina filler containing polyester polymer concretes reached 11.02 and 10.93 kN, respectively, of flexural strength, while the ladle slag samples showed the best result with 19.31 kN. In the compressive strength test, the sand and alumina filler combinations reached 106.16 and 104.21 MPa, respectively, while the ladle slag achieved 160.48 MPa. The flexural and compressive elasticity modulus showed similar trends related to the resin content.
Open Access
Assessment of the ability of MGO based binary binders for the substitution of Portland cement for mortars manufacturing
(Elsevier, 2022) Seco Meneses, Andrés; Espuelas Zuazu, Sandra; Marcelino Sádaba, Sara; Echeverria Lazcano, Angel María; Del Castillo García, Jesús María; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Gobierno de Navarra / Nafarroako Gobernua
This article evaluates the ability of a magnesia kiln dust (PC-8) and a commercial calcined MgO (MCB100), combined with ground granulated blastfurnace slag (GGBS), as constituents of binary M-S-H binders. Mortars and pastes were manufactured and their properties were compared to those of Portland Cement (PC). MgO-based mortars showed an increase in setting time and higher fresh consistency. At earlier ages MgO mortars showed lower mechanical properties. At 90 days both MgO-based mortars overcame the PC flexural strength and PC-8 + GGBS also overcame its compressive strength. X-Ray Diffraction and Thermogravimetry tests demonstrated the presence of M-S-H in the pastes.
Open Access
Recycled granulates manufacturing from spent refractory wastes and magnesium based binder
(Elsevier, 2023) Seco Meneses, Andrés; Del Castillo García, Jesús María; Perlot, Céline; Marcelino Sádaba, Sara; Espuelas Zuazu, Sandra; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC
This paper analyzes the ability of two Spent Refractory Wastes (SRW) for the manufacturing of recycled granulates for construction applications. A binary magnesium oxide and ground granulated blast furnace slag hydraulic binder was considered as an agglomerating agent for the granulates manufacturing. Influence of curing atmosphere was carried out: in air, 20 % CO2 and 100 % CO2 atmosphere up to 28 days. Granulometry, thermal analysis, particle density, bulk density, water absorption and mechanical strength tests were performed to characterize the granulates. SRW showed their ability for the granulates manufacturing. Results demonstrated the existence of a residual reactivity of the wastes considered. A direct relationship between the CO2 content of the curing atmosphere and the granulates hydration degree was observed. Carbonation process increased from 7 days to 28 days and direct relationships were observed between the CO2 content and the carbonation degree as well as between the binder dosage and the carbonation degree. CO2 curing reduced the water absorption and increased the compressive strength of the granulates.
Open Access
Sulphate soil stabilisation with magnesium binders for road subgrade construction
(Taylor and Francis, 2020) Seco Meneses, Andrés; Espuelas Zuazu, Sandra; Marcelino Sádaba, Sara; García, Beñat; Del Castillo García, Jesús María; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Gobierno de Navarra / Nafarroako Gobernua
This paper analyzes the ability of magnesium oxide-based additives to stabilise a low bearing gypsum marly soil, in order to reach subgrade requirements. This soil was not adequate for stabilisation with lime or cement because of its high sulphate content. Binders considered in this investigation were composed of three reactive Mg products and by products, both with and without ground granulated blast furnace slags (GGBS). They were compared to two cements and an aerial lime as soil stabilisers in a laboratory investigation and a field trial. Laboratory tests showed that Mg products with GGBS reached strength results close and at times even better than those of cement. One of the Mg products was the only additive able to reduce the natural soil swelling. Leaching tests demonstrated the ability of the Mg products to reduce the soil leaching of substances like calcium, magnesium, sulphate and chloride. In field trials two of the Mg products combined with GGBS met the bearing capacity requirements for subgrades, in accordance with the Spanish standard.
Open Access
Sustainable unﬁred bricks manufacturing from construction and demolition wastes
(Elsevier, 2018) Seco Meneses, Andrés; Omer, Joshua; Marcelino Sádaba, Sara; Espuelas Zuazu, Sandra; Prieto Cobo, Eduardo; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
The management of construction and demolition wastes is a huge challenge for most Governments. Thegreatest component of such wastes is concrete and masonry fragments or remains. Among the most com-mon approaches to valorization of such w astes is to convert them to recycled aggregates, however thismay be hampered by low quality of some recycled aggregates compared to natural aggregates. This paperpresents the results of experimental investigation where concrete and ceramic remains were used to par-tially substitute clay soil in producing unﬁred bricks. The bricks were then tested for mechanical strength,water absorption freeze-thaw resistance. Additionally the environmental impact of the bricks wasassessed based on Life Cycle Analysis (LCA). It was established that concrete waste could be used to sub-stitute up to 50% of the clay whereas ceramic wastes could only substitute a maximum of 30% of the clay.Blended bricks made from clay and concrete waste mixes had a lower mechanical strength than thosemade from clay and ceramic waste. As regards water absorption, there was no marked differencebetween the two blends of brick however reduction in water resistance was slightly greater in bricks con-taining concrete waste that in those containing ceramic wastes. Also, tests showed that freeze-thawresistance was greater in bricks blended with concrete wastes than in those incorporating ceramicwastes. Life Cycle analyses demonstrated that it is the binder content in the mix that largely determinesthe environmental impact of the blended bricks. Lastly, it was demonstrated that the most desirable tech-nical and environmental credentials of brick material mixes resulted from using the binder combination:CL-90-S+GGBS 2/8.
Open Access
Technical and environmental characterization of hydraulic and alkaline binders
(Elsevier, 2018) Espuelas Zuazu, Sandra; Echeverria Lazcano, Angel María; Marcelino Sádaba, Sara; Prieto Cobo, Eduardo; Seco Meneses, Andrés; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak; Gobierno de Navarra / Nafarroako Gobernua, 0011-1365-2017-000176
Portland cement is a widely used binder in construction and building applications because of its good properties. Despite its convenience as construction material, the social demands and policies trends are requesting a lower impact and more sustainable cement manufacturing industry. The most effective ways to reach this goal are the substitution of clinker by different wastes or by-products in the cement composition or the development of more sustainable binders like the alkali activated binders. This work analyzes from a technical and environmental point of view the substitution of a clinker based CEM I common cement for the construction mortars manufacturing. Four common cements with different ground granulated blastfurnace slags (GGBS) or fly ashes (FA) contents as well as fifteen alkali activated binders (AAB) combinations were considered. Fresh consistency, density, compressive strength (CS) tests and life cycle analysis were carried out to state the ability of these different hydraulic and alkaline activated binders for the CEM I substitution. The results obtained demonstrated the technical and environmental convenience of these binders for the construction mortars manufacturing.
Open Access
Experimental study of the valorization of sulfate soils for use as construction material
(MDPI, 2022) Seco Meneses, Andrés; Del Castillo García, Jesús María; Perlot, Céline; Marcelino Sádaba, Sara; Prieto Cobo, Eduardo; Espuelas Zuazu, Sandra; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
This article shows an experimental investigation carried out for the stabilization of a sulfate soil. The stabilization was carried out in two phases: the first phase was the consumption of the sulfate present in the soil through its controlled transformation into ettringite. After this, a modified soil with lower maximum density, greater optimum moisture identified via standard proctor (SP) test, no plasticity and improved unconfined compressive strength (UCS) was obtained. In the second phase, the modified soil was stabilized by the use of different additives rich in oxides of calcium or magnesium, combined with by-products or waste materials containing reactive aluminum or silicon oxides. As a result, the mechanical strength of the modified soil was improved. In this phase, a binary binder composed of a magnesium oxide product and ground granulated blast-furnace slags (GGBS) obtained the highest UCS. The binary binder composed of lime and an alumina filler formed ettringite in the treated soil. This experiment allowed for the validation of a two-phase stabilization process and the non-conventional additives used, mainly magnesium oxide and GGBS, even for high-bearing-requirement pavement layers’ construction.
Open Access
Durability of polyester polymer concretes based on metallurgical wastes for the manufacture of construction and building products
(Elsevier, 2020) Seco Meneses, Andrés; Echeverria Lazcano, Angel María; Marcelino Sádaba, Sara; García, Beñat; Espuelas Zuazu, Sandra; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería
Varied target materials can be incorporated into polyester polymer concretes (PPC). This allows natural aggregates to be substituted for different waste products in non-structural polymeric construction and building materials. Many studies have explored the mechanical properties of waste-based PPC, but the durability and surface resistance of these materials is not fully known. In this study, we compared the suitability of two metallurgical wastes to that of two natural aggregates for manufacturing durable PPC products. Durability against environmental conditions, durability against chemical products, and surface strength against physical damage were tested. Durability against environmental conditions was characterised according to visual damage and mechanical strength losses after freezing-thawing; no PPC combinations exhibited surface damage following the ageing cycles. The ladle slag (LS) samples exhibited the best pre- and post-test flexural and compressive strength. The properties of the alumina filler (AF) combinations exhibited the highest flexural and compressive strength losses after freezing-thawing. The calcareous sand combinations were damaged most severely by acid, while LS and AF exhibited good resistance against chemical substances. The LS combinations exhibited the highest surface strength against impacts in the rebound number test, while the results obtained for the AF combinations were close to those of natural aggregates. The surface resistance against scratching depended on the resin, not on the target material.