Departamento de Ingeniería Química, Ambiental y de los Materiales
URI permanente para esta comunidadhttps://hdl.handle.net/10953/42
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Examinando Departamento de Ingeniería Química, Ambiental y de los Materiales por Materia "Alkali-activated cements"
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Ítem Alkaline-activated cements synthesized from spent diatomaceous earth and different industrial sludge ashes(Taylor & Francis, 2025-07-29) Felipe-Sesé, Manuel; García-Díaz , Almudena; Gómez-Casero, Miguel Ángel; Eliche-Quesada, DoloresThis study evaluates the technological properties of alkali-activated cements (AACs) produced from spent diatomaceous earth (SDE), a by-product of beer filtration, combined with 20wt.% of industrial sludge ashes. The ashes used include brewery sludge ash (BSA), oil industry sludge ash (OSA), pulp–paper sludge ash (PSA), and aluminum anodizing sludge ash (AASA). Activation was carried out using a 1:1 mixture of sodium silicate and sodium hydroxide, with curing at room temperature for 7 and 28 days. Microstructural analysis was performed using X-ray diffractometer (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). The results show that the chemical composition of the sludge ashes significantly influences the mechanical performance of AACs. Calcium-rich wastes improved compressive strength, while the presence of SO3 and P2O5 reduced it due to the formation of expansive phases or secondary reactions. The best results were achieved with BSA-SDE cements, which reached compressive and flexural strengths of 30.0 and 6.5MPa, respectively.Ítem Effect of olive-pruning fibres as reinforcements of alkali-activated cements based on electric arc furnace slag and biomass bottom ash(Springer Nature, 2024-03-18) Gómez-Casero, Miguel Ángel; Sánchez-Soto, Pedro José; Castro-Galiano, Eulogio; Eliche-Quesada, DoloresIn this work, alkali-activated composites using electric arc furnace slag (50 wt%) and biomass bottom ash (50 wt%) were manufactured, adding olive-pruning fibres as reinforcement. The objective of adding fibres is to improve the flexural strength of composites, as well as to prevent the expansion of cracks as a result of shrinkage. For this reason, composites reinforced with olive-pruning fibres (0.5–2 wt%) untreated and treated with three different solutions to improve matrix–fibre adhesion were manufactured. Treatments developed over fibres were a 10 wt% Na2SiO3 solution, 3 wt% CaCl2 solution and 5 wt% NaOH solution. Mechanical properties, physical properties, thermal properties and the microstructure of composites by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were studied to demonstrate the improvement. Alkaline treatment degraded fibre surface, increasing the matrix–fibre adhesion, and as a consequence, flexural strength increased up to 20% at 90 days of curing. Optimal results were obtained with composites reinforced with 1 wt% of olive-pruning fibre treated by a 10 wt% Na2SiO3 solution. Higher quantity of olive-pruning fibre leads to local agglomeration, which weakens the matrix–fibre adhesion. The effect on the compressive strength is less evident, since the addition of fibres produces an admissible decrease (between 0 and 9% using 0.5 or 1 wt% of fibres), except in composites that use olive pruning treated with 10 wt% Na2SiO3 solution, where values remain stable, similar or better to control paste. A greater ductility of the matrix in all composites was observed. Furthermore, the alkali-activated cement matrix was bonded to olive-pruning fibre better than untreated fibre, as it is shown in SEM images. Thus, the results showed that olive-pruning fibres could be used as reinforcement in the manufacturing of alkali-activated materials when they are treated with alkali solutions.