Open Access
Sulfate soils stabilization with magnesium-based binders
(Elsevier, 2016) Seco Meneses, Andrés; Miqueléiz Jiménez, Luis; Prieto Cobo, Eduardo; Marcelino Sádaba, Sara; García, Beñat; Urmeneta, Pablo; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Sulfate soils' stabilization is a very interesting subject with technical, economic and environmental implications. The difficulty of their stabilization is due to the fact that the usual stabilizer additives are based on calcium. In these soils, sulfate combines with the calcium from the additive and the aluminum from the clay, resulting in a highly hydrated expansive mineral named ettringite. This provokes the swelling of the treated material and even its destruction. This study analyzes the result of the substitution of the calciumbased additives by one alternative additive based on magnesium, an industrial byproduct named PC-8, in the stabilization of five different sulfate soils. From a mechanical point of view soils treated with PC-8 reached similar resistance values to the lime treated ones, of about 2–3 MPa for 4% dosage and 2–5 MPa for 8% dosage, being usually better with the PC-8 results than with the lime ones. When PC-8 was combined with GGBS the resistance values increased up to 11–13 MPa and the lime-GGBS reached the 6–7 MPa. The natural swelling of the soils treated with PC-8 decreased substantially and maintained constant even for immersion at long-term. In the case of the soils treated with lime, long-termswelling increased up to very high values even in the case of soilswithout natural swelling. XRD analysis of these samples demonstrated the existence of ettringite in 4 of the 5 soilswhen theywere treated with lime and there was not expansive minerals in the PC-8 treated soils, agreeing with the swelling observed behavior of the soils when treated with both additives.
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
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
A biological insight of hops wastes vermicomposting by Eisenia Andrei
(Springer, 2024) González Moreno, Miguel Ángel; García Gracianteparaluceta, Beñat; Marcelino Sádaba, Sara; Prieto Cobo, Eduardo; Seco Meneses, Andrés; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The study was conducted to assess the feasibility of using Eisenia andrei earthworms for vermicomposting hop remains from a lupulin extraction enterprises for the brewing industry. Vermicomposting process was conducted within 70 days using hop (Humulus lupulus) wastes blended with horse manure at five different ratios for triplicate in laboratory conditions. Number of worms, cocoons, and hatchlings were observed and recorded weekly as earthworm biomass, population build-up and reproduction biological parameters. The results showed an indirect relationship between the hop content and the growth and reproductive performance of the worms. Notwithstanding this fact, 100% of survival occurred in all combinations. A 50% blend of hop wastes and horse manure is suggested to ensure the optimizing usefulness of E. andrei. In addition, moment of maximum splendour of worm population build-up and reproduction parameters measured was achieved at around 40 or 50 days since the beginning of the test, seeing a clear and widespread decline from that moment.
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
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
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
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.