Fired clay-based construction and demolition waste as pozzolanic addition in cements. Design of new eco-efficient cements

Asensio, Eloy; Medina, César; Frías, Moisés; Rojas, María Isabel Sánchez de

doi:10.1016/j.jclepro.2020.121610

Cited by 43 publications

(15 citation statements)

References 62 publications

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“…The H-WG T25-2 pastes exhibited greater strength than the HN T25-2 pastes due to the extra soluble silica (sourced from the WG) in the medium and the early formation of reaction product [53,57,58]. As expected, an inverse relationship was observed between compressive strength and mean pore size (see Table 5), a finding consistent with earlier reports [59][60][61].…”

Section: Hybrid Cement Paste Compressive Strength and Mean Size Poresupporting

confidence: 90%

Hybrid Cements: Mechanical Properties, Microstructure and Radiological Behavior

et al. 2022

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The use of more eco-efficient cements in concretes is one of the keys to ensuring construction industry sustainability. Such eco-efficient binders often contain large but variable proportions of industrial waste or by-products in their composition, many of which may be naturally occurring radioactive materials (NORMs). This study explored the application of a new gamma spectrometric method for measuring radionuclide activity in hybrid alkali-activated cements from solid 5 cm cubic specimens rather than powder samples. The research involved assessing the effect of significant variables such as the nature of the alkaline activator, reaction time and curing conditions to relate the microstructures identified to the radiological behavior observed. The findings showed that varying the inputs generated pastes with similar reaction products (C-S-H, C-A-S-H and (N,C)-A-S-H) but different microstructures. The new gamma spectrometric method for measuring radioactivity in solid 5 cm cubic specimens in alkaline pastes was found to be valid. The variables involved in hybrid cement activation were shown to have no impact on specimen radioactive content. The powder samples, however, emanated 222Rn (a descendent of 226Ra), possibly due to the deformation taking place in fly ash structure during alkaline activation. Further research would be required to explain that finding.

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Section: Hybrid Cement Paste Compressive Strength and Mean Size Poresupporting

confidence: 90%

Hybrid Cements: Mechanical Properties, Microstructure and Radiological Behavior

et al. 2022

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“…The EDX analysis (ten analyses/gel) showed that the Ca/Si ratio in the OPC gel was 2.0, compared to 1.7 in M1 and 1.9 in M2. The findings also showed that adding SCMs induced aluminium uptake in the gel, as reported earlier by other authors who used pozzolanic additions to partially replace clinker [22,24,36,57]. Inasmuch as the aluminium may have replaced Si in the gel structure, those findings would explain the lower Ca/Si ratio in the pastes bearing SCMs.…”

Section: Sem/edx Microstructural Analysissupporting

confidence: 86%

“…Its filler effect likewise-identified would favour hydration, providing nucleation sites that would densify the cement matrix microstructure. Masonry and mixed C&DW ultrafines [19][20][21][22] comprise essentially SiO 2 , Al 2 O 3 and Fe 2 O 3 (SiO 2 + Al 2 O 3 + Fe 2 O 3 ≥ 84%), with pozzolanicity at least as high as fly ash and similar to that of other masonry materials, such as masonry [4,23] and fired clay sanitary ware [24] rubble. Further to research on mechanical behaviour, GRC has no adverse effect on new eco-cement performance at low replacement ratios (≤7%), whereas masonry ultrafines induce no significant decline in compressive or flexural strength at percentages of up to 25%.…”

Section: Introductionmentioning

confidence: 99%

Durability of Ternary Cements Based on New Supplementary Cementitious Materials from Industrial Waste

et al. 2021

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Cement-based materials decay with exposure to aggressive agents, a development that raises infrastructure operation and maintenance costs substantially. This paper analyses the inclusion of ultrafine construction and demolition (UC&DW) and biomass-fuelled power plant (BA) waste as pozzolanic additions to cement in pursuit of more sustainable and eco-respectful binders and assesses the durability of the end materials when exposed to seawater, chlorides (0.5 M NaCl) or sulphates (0.3 M Na2SO4). The effect of adding silica fume (SF) at a replacement ratio of 5% was also analysed. Durability was determined using the methodology proposed by Koch and Steinegger, whilst microstructural changes were monitored with mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and scanning electron microscopy (SEM) for a fuller understanding of decay processes. According to the findings, the new blended cements containing 20%UC&DW + 10%BA or 20%UC&DW + 20%BA + 5%SF resist the attack by the aggressive media studied, with a 56-d corrosion index of over 0.7. The composition of the reaction products generated with the attack is essentially the same in OPC and the SCM-bearing materials. The results show that the optimal replacement ratio for SCM is 30%.

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“…Parte de esta prioridad es el enorme potencial que presentan estos RCDs para el cumplimiento de los objetivos de desarrollo sostenible(ODS) y de la economía circular, recuperando estos residuos como materias primas secundarias para el propio sector de la construcción [6,7]. Con este objetivo, el aprovechamiento de estos residuos, por su heterogeneidad, pasa por las plantas de tratamientos de RCDs para la selección de los diferentes materiales presentes: hormigón reciclado, cerámico, mixto, papel, plásticos, madera, hierro, etc, [8][9][10][11][12]. Uno de estos residuos RCDs que están centrando especial interés en la comunidad científica son los residuos de hormigón reciclado, por estar recogidos en diferentes instrucciones y recomendaciones como árido grueso reciclado en la fabricación de nuevos hormigones ecológicos [13].…”

Section: Introductionunclassified

Nuevos cementos eco-eficientes elaborados con la fracción fina de hormigón reciclado para futuras aplicaciones ingenieriles

Monasterio¹,

Frías²,

García³

et al. 2021

Congreso Latino-Americano De Patología De Construcción

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Los residuos de la construcción son un gran problema medioambiental. Europa ha priorizado su reciclaje para nuevas construcciones ingenieriles. Sin embargo, la fracción fina de los residuos de hormigón, no presenta aplicaciones y son almacenados en las plantas de tratamiento. Este trabajo investiga el comportamiento de pastas de cemento elaboradas con un 7% de la fracción fina de hormigón de diferente naturaleza. Los resultados muestran que estos residuos presentan poca actividad puzolánica y sus propiedades físicas y mecánicas son muy similares a la pasta de cemento. A pesar de ello, los cementos mezcla cumplirían con la normativa para cementos comunes. Esto abre una vía para reutilizar estos residuos en nuevas tecnologías de construcción como puede ser impresión 3D. Palabras clave:Fracciones finas de hormigón reciclado; caracterización; propiedades de las pastas de cemento mezcla; nuevas aplicaciones ingenieriles. RESUMO

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Fired clay-based construction and demolition waste as pozzolanic addition in cements. Design of new eco-efficient cements

Cited by 43 publications

References 62 publications

Hybrid Cements: Mechanical Properties, Microstructure and Radiological Behavior

Hybrid Cements: Mechanical Properties, Microstructure and Radiological Behavior

Durability of Ternary Cements Based on New Supplementary Cementitious Materials from Industrial Waste

Nuevos cementos eco-eficientes elaborados con la fracción fina de hormigón reciclado para futuras aplicaciones ingenieriles

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