Browsing by Author "Vigil de la Villa, Raquel"
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Item Durability of Construction and Demolition Waste-Bearing Ternary Eco-Cements(2022-04-16) Moreno-Juez, Jaime; Caneda-Martínez, Laura; Vigil de la Villa, Raquel; Vegas, Iñigo; Frías, Moisés; Tecnalia Research & Innovation; TRAZABILIDAD CIRCULAR; GENERALIn recent years, the development of ternary cements has become a priority research line for obtaining cements with a lower carbon footprint, with the goal to contribute to achieve climate neutrality by 2050. This study compared ordinary Portland cement (OPC) durability to the performance of ternary cements bearing OPC plus 7% of a 2:1 binary blend of either calcareous (Hc) or siliceous (Hs) concrete waste fines and shatterproof glass. Durability was measured further to the existing legislation for testing concrete water absorption, effective porosity, pressurized water absorption and resistance to chlorides and CO2. The experimental findings showed that the 7% blended mortars performed better than the reference cement in terms of total and effective porosity, but they absorbed more pressurized water. They also exhibited lower CO2 resistance, particularly in the calcareous blend, likely due to its higher porosity. Including the binary blend of CDW enhanced chloride resistance with diffusion coefficients of 2.9 × 10−11 m2 s−1 (calcareous fines-glass, 7%Hc-G) and 1.5 × 10−11 m2 s−1 (siliceous fines-glass, 7%Hs-G) compared to the reference cement’s 4.3 × 10−11 m2 s−1. The siliceous fines-glass blend out-performed the calcareous blend in all the durability tests. As the mortars with and without CDW (construction and demolition waste) performed to similar standards overall, the former were deemed viable for the manufacture of future eco-efficient cements.Item The Influence of Activated Coal Mining Wastes on the Mineralogy of blended cement pastes(2016-01-01) Frias, Moises; Rodriguez, Olga; Vigil de la Villa, Raquel; Garcia, Rosario; Martinez-Ramirez, Sagrario; Fernandez-Carrasco, Lucia J.; Vegas, Iñigo; GENERALIn recent years, kaolinite-based wastes are focusing the attention of researchers to obtain recycled metakaolinite, with consequent environmental and socioeconomic benefits. One of these lines of research is based on coal mining waste, which once activated thermally, it becomes a highly pozzolanic product (ACM). This study reports the influence of activated carbon mining waste on the formation and evolution of the mineralogical phases in the ACM/cement system as well as their influence on the microstructure up to 90 d of reaction. Mineralogical analyses clearly show that the addition of ACM modified mineralogical compounds of blended cements. The C4AH13 and C4A CH12 were the predominant phases in this type of cements; while in the ordinary portland cement cements, portlandite, ettringite, and carboaluminate were main hydrated phases. Two differential zones in the pore size distribution of the C–S–H gels at 12 and 4.5 nm were observed, predominating the formation of C–S–H gels at 12 nm when 20% of ACM was added to the cement.