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
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
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
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
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
Characterization of biomass briquettes from spent coffee grounds and xanthan gum using low pressure and temperature
(Springer, 2020) Seco Meneses, Andrés; Espuelas Zuazu, Sandra; Marcelino Sádaba, Sara; Echeverria Lazcano, Angel María; Prieto Cobo, Eduardo; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Gobierno de Navarra / Nafarroako Gobernua
This paper analyzes the ability of the SCG for briquettes production based on the use of xanthan gum as binder under low-pressure and low-temperature biomass manufacturing conditions. Briquettes were manufactured at room temperature, at 10, 15, 20, 25, and 30% of moisture content and 8, 10, and 12 MPa of compaction pressure. Raw SCG samples reached dry densities between 0.669 and 0.735 g/cm3 for the samples with a moisture content of 15% and 8 MPa and 10% and 12 MPa, respectively. Samples treated with 10% of xanthan gum got densities between 0.672 and 0.819 g/cm3 depending on the moisture content and the compaction pressure. No one of the raw SCG combinations passed the durability test meanwhile xanthan ones with 30% of moisture content obtained the best results with a loss of mass of 9.1% for the combination compacted at 10 MPa. Raw SCG samples showed water absorption values between 0.498% and 0.846%, meanwhile xanthan samples water absorption oscillated between 0.427% and 1.065%. Xanthan gum increased the SCG ashes content from 0.66% to 0.97% and decreased the lower heating value (LHV) from 25,399 J/g of the pure raw SCG to 23,503 J/g. Thermogravimetric tests showed that xanthan gum mix compared to the raw SCG increased as well the volatile peak from 61.54 mW to 81.94 mW as the mass loss rate in the volatile stage from −0.0178 mg/s to −0.0184 mg/s.