Open Access
Project risk management methodology for small firms
(Elsevier, 2014) Marcelino Sádaba, Sara; Pérez Ezcurdia, Amaya; Echeverría Lazcano, Amparo; Villanueva Roldán, Pedro; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería
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
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
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.
Open Access
Recovered foam impact absorption systems
(MDPI, 2024-10-19) Marcelino Sádaba, Sara; Benito Hernández, Pablo; Martín Antunes, Miguel Ángel; Villanueva Roldán, Pedro; Veiga Suárez, Fernando; Ingeniería; Ingeniaritza
The use of foam materials in environments where they come into contact with individuals often results in deterioration, necessitating periodic replacements to maintain safety and hygiene standards. Foam, a lightweight, porous plastic formed by aggregated bubbles, possesses excellent impact-absorbing properties; however, its inherent porosity and susceptibility to wear present challenges. This project aims to develop a technological application for repurposing spent polyurethane (PU) foam from leisure facilities into effective impact absorption systems. By focusing on the reuse of deteriorated foam materials, this initiative seeks to minimize environmental impact while leveraging their beneficial technical characteristics. Addressing issues related to foam degradation, this project endeavors to create sustainable solutions by reintegrating spent foam into new systems. This innovative approach promotes sustainability while enhancing safety through the provision of high-quality, impact-resistant elements. Ultimately, this work aims to contribute to environmental conservation and the advancement of effective impact protection measures in leisure facilities.
Open Access
Experimental study of the performance and emission characteristics of an adapted commercial four-cylinder spark ignition engine running on hydrogen-methane mixtures
(Elsevier, 2014) Diéguez Elizondo, Pedro; Urroz Unzueta, José Carlos; Marcelino Sádaba, Sara; Pérez Ezcurdia, Amaya; Benito Amurrio, Marta; Sáinz Casas, David; Gandía Pascual, Luis; Ingeniería; Ingeniaritza
The use of hydrogen/methane mixtures with low methane contents as fuels for internal combustion engines (ICEs) may help to speed up the development of the hydrogen energy market and contribute to the decarbonization of the transportation sector. In this work, a commercial 1.4 L four-cylinder Volkswagen spark-ignition engine previously adapted to operate on pure hydrogen has been fueled with hydrogen/methane mixtures with 5–20 vol.% methane (29.6–66.7 wt.%). An experimental program has been executed by varying the fuel composition, air-to-fuel ratio (λ), spark advance and engine speed. A discussion of the results regarding the engine performance (brake torque, brake mean effective pressure, thermal efficiency) and emissions (nitrogen oxides, CO and unburned hydrocarbons) is presented. The results reveal that λ is the most influential variable on the engine behavior due to its marked effect on the combustion temperature. As far as relatively high values of λ have to be used to prevent knock, the effect on the engine performance is negative. In contrast, the specific emissions of nitrogen oxides decrease due to a reduced formation of thermal NOx. A clear positive effect of reducing the spark advance on the specific NOx emissions has been observed as well. As concerns CO and unburned hydrocarbons (HCs), their specific emissions increase with the methane content of the fuel mixture, as expected. However, they also increase as λ increases in spite of the lower fuel concentration due to a proportionally higher reduction of the power. Finally, the effect of the increase of the engine speed is positive on the CO and HCs emissions but negative on that of NOx due to improved mixing and higher temperature associated to intensified turbulence in the cylinders.
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
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
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.