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
Stabilization of a clay soil using cementing material from spent refractories and ground-granulated blast furnace slag
(MDPI, 2021) Seco Meneses, Andrés; Del Castillo García, Jesús María; Espuelas Zuazu, Sandra; Marcelino Sádaba, Sara; García Gracianteparaluceta, Beñat; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC
Nowadays, huge amounts of refractory materials are generated around the world. The majority of them lack valorization methods. This study analyzes the ability of a doloma and two magnesia spent refractory wastes as soil stabilizers on their own, as well as when combined with Ground-Granulated Blast Furnace Slags (GGBS). These materials showed a limited ability for the soil’s plasticity modification from a plasticity index of 15.6 to a minimum of 12.7. The high pH of the additives increased the soil’s pH from 7.88 to values in the range of 10.94–11.25 before the 28 days, allowing the development of the pozzolanic reactions. Unconfined compressive strength (UCS) increased along the curing time, reaching a maximum value of 5.68 MPa after 90 days. Based on the UCS, the optimum refractory GGBS ratios oscillate between 30:70 and 50:50. The UCS values after soaking samples reduced the unsoaked results between 68.70% to 94.41%. The binders considered showed a low effect against the soil swelling and the lack of delayed expansive effects because of the MgO hydration. Finally, X Ray Diffraction (XRD) tests showed that the stabilization only slightly modified the combinations of mineralogy and the formation of Magnesium Silicate Hydrate (MSH) gels.
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
Mechanochemical activation of non-conventional precursors for use as suplementary cementitious materials
(Elsevier, 2025-03-15) Seco Meneses, Andrés; Martín Antunes, Miguel Ángel; Espuelas Zuazu, Sandra; Fernández Jiménez, Ana; Prieto Cobo, Eduardo; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC
This work analyzes the effect of Mechanochemical Activation (MA) of a Commercial low-grade kaolinite and low- grade illite, a feldspar, a diatomite and a clayey soil (non-commercial) as supplementary cementitious materials. Milling was conducted at different times for up to 360 min. MA decreased the particles size and increased the specific surface area except for low-grade illite. However, prolonged milling produced agglomeration in feldspar, diatomite and clayey soil. MA partially reduced diffractogram peaks and modified the dehydroxylation losses of mass in the thermogravimetric tests. MA's effect over the solubility of SiO 2 and Al 2 O 3 was not conclusive, with differences among aluminosilicate minerals and with no relationships with their physical parameters or chemical structures. Feldspar was the only one not to show Strength Activity Index (SAI) increases due to MA. Low-grade illite, feldspar and diatomite combinations surpassed 75 % on the SAI. No clear relationships were observed between the combinations SAI and their physical parameters, chemical structure or SiO 2 and Al 2 O 3 availability.
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.
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
Valorization of insulation cellulose waste as solid biomass fuel
(MDPI, 2021) Espuelas Zuazu, Sandra; Marcelino Sádaba, Sara; García, Beñat; Seco Meneses, Andrés; Del Castillo García, Jesús María; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua
This paper investigates the ability of insulation cellulose fiber powder (CFP) to be pelletized for its valorization as biomass fuel. CFP is a waste originating from insulation cellulose manufacturing that lacks any method of valorization because of its boron salts content. A sugar byproduct and lignosulfonate (LS) were considered as binders for the pellet manufacturing process. Physical tests were carried out to characterize the pellets’ performance. Chemical and combustion tests were considered to state the pellets’ potential as a green energy source. Raw CFP showed good ability in its pelletization and durability in the range of 15–30% of moisture content. The pellet’s density decreased as water content increased. Binders increased the pellet’s length before and after the durability test. Binders also increased the CFP pellet’s water absorption, demonstrating a potential decrease in durability against environmental factors. Binders also decreased the lower heating value. Ultimate analysis showed a slight Nitrogen increase in both binder combinations that could potentially raise the pollutant NOx combustion emissions. All the combinations showed adequate combustion characteristics, but binders increased ash production. Additives decreased the CFP volatile matter content and increased the fixed carbon, which could facilitate a more stable combustion. DTA curves showed a mass loss rate decrease in the volatile stage for the binder combinations, which also could be considered as an indicator of a more stable combustion. The ashes’ chemical compositions when analyzed by XPS showed boron contents oscillating between 10.03% and 16.42%, demonstrating the possibility of recovering them from the combustion ashes.
Open Access
Fresh, mechanical, and microstructural properties of sustainable mortars made of two recycled sands from construction and demolition wastes
(American Society of Civil Engineers, 2025-04-28) Seco Meneses, Andrés; Martín Antunes, Miguel Ángel; Espuelas Zuazu, Sandra; Marcelino Sádaba, Sara; Prieto Cobo, Eduardo; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Gobierno de Navarra / Nafarroako Gobernua
This paper analyses the ability of two recycled sands (RSs) from concrete (CON) and masonry (MAS) wastes for the manufacture of mortars for the construction industry. Manufactured sand (MS) was substituted by both RSs at the rates of 25%, 50%, 75%, and 100%. CON combinations did not demonstrate any correlation between workability and the MS replacement ratio, whereas MAS combinations exhibited a direct relationship between these factors. A decrease in the starting and final setting times was observed for both RS combinations and, in general, longer total setting times. CON combinations showed mechanical strength increases for substitution rates between 25% and 50%, whereas MAS reached improved mechanical strength at 25%. Scanning electron microscopy-energy dispersive X-ray (SEM-EDX)-demonstrated tests allowed for mortar microstructure differences and hydration product formation. Thermogravimetric analysis/derivative thermogravimetry (TG/DTG) tests showed hydrated cementitious compounds' formation differences and the consumption of Portlandite between combinations and their evolution during curing.
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
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.