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
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
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
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
Challenges in Life Cycle Assessment (LCA) of stabilised clay-based construction materials
(Elsevier, 2017) Marcelino Sádaba, Sara; Kinuthia, John; Oti, Jonathan; Seco Meneses, Andrés; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
The preference of clay-based materials for sustainable construction is well-established. The establishment ofsustainability credentials of emergent construction materials is very subjective, and most available tools are notfully equipped to deal with individual material systems, such as composite cement- or lime-based cementitioussystems, including clay-based blocks and bricks. The main problem emanates from the challenges of the audit ofeach aspect of the material processing, and especially the quantification of the most relevant inputs into thecomposite product. The variability in material ingredients, and lack of data for each aspect of the manufacturingprocesses involved creates major challenges. Incorporation of materials with long and complex recyclingprocesses further exacerbate the challenge. These incorporations create problems in terms of accurate materialtrails and data for input in a robust Life Cycle Assessment (LCA) of individual products. This paper reports on asimplified approach towards full LCA of seven clay-based brick products developed in UK (4) and Spain (3), based on known material data and estimated energy inputs in the manufacturing processes. The UK-based brickscomprise of Lower Oxford Clay (LOC), stabilised using combinations of hydrated lime, Ground Granulated Blast-furnace Slag (GGBS) and Portland cement (PC). In order to test the robustness of the proposed approach, resultson UK-based bricks are compared with a parallel LCA on clay-based product developed in Spain. Finally, theclay-based products are compared with a typical Portland cement-based concrete block andfired clay brick. Inthe LCA, boundary conditions includefixed transport, thus attempting to factor only the material ingredients,their known atmospheric emissions, and estimated energy inputs during processing. Results suggest that themost challenging aspect in the undertaking of LCA is the availability of reliable input data. Results also show thatthere are numerous parameters that can reliably and corroboratively facilitate the comparison of performance, besides carbon dioxide emissions.
Open Access
Monitoring water vapour with GNSS during a heavy rainfall event in the Spanish Mediterranean area
(Taylor & Francis, 2017) Priego, E.; Jones, J.; Porres, M. J.; Seco Meneses, Andrés; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
The Spanish Mediterranean area is periodically affected by torrential rainfall events during autumn. In September 2012, one of these episodes took place with up to 50 mm of rain in a 1-hour period and with more than 300 mm in 12 hours. This study shows the spatial and temporal variability of the atmospheric integrated water vapour (IWV) observed using delays in Global Navigation Satellite System (GNSS) signals and associated rainfall during this severe weather event. This experiment focuses on the relationship between the variations of IWV values in GNSS stations and meteorological variables such as atmospheric pressure and precipitation. This study was carried out on the Mediterranean coast of Spain during a heavy rainfall episode. The results show a mean increase in IWV of around 30 kg/m2 occurring prior to heavy precipitation. They further revealed an increase of up to a 100% in IWV values in several GNSS stations available in the study area. Fluctuations in IWV fields correlate well with approaching frontal rainfall and a combined rise in IWV and a drop in atmospheric pressure may well be used as a pre-cursor to heavy precipitation.
Open Access
Estimated and real durability of unﬁred clay bricks: Determining factorsand representativeness of the laboratory tests
(Elsevier, 2016) Seco Meneses, Andrés; Urmeneta, Pablo; Prieto Cobo, Eduardo; García, Beñat; Miqueléiz Jiménez, Luis; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
This paper presents an analysis of the representativeness of the main laboratory tests and the real dura-bility of earth-based construction materials. For this study, a natural marl soil, mixed with different per-centages of silica sand, was treated with portland cement, hydraulic lime, a mix of lime and groundgranulated blastfurnace slag and other binder composed of a high magnesium oxide waste mixed withground granulated blastfurnace slag. All the combinations were characterized based on the usual dura-bility related laboratory tests as are: maximum density, unconﬁned compressive strength, wetting anddrying, Swinburne accelerated erosion resistance, capillarity water absorption, total water absorptionand freeze/thawing cycles. The results of these tests have been related to the real durability of the sam-ples for eighteen months of outdoor exposure. They revealed the positive effect of sand adding in thematerials durability and the great result of the binder based on magnesium oxide with ground granulatedblastfurnace slag. It was also demonstrated the representativeness of the water absorption test as a dura-bility indicator of earth based construction materials durability.