Resumo

MARTINEZ-GUTIERREZ, Fabio; VALENCIA-SAAVEDRA, William Gustavo  e  MEJIA-DE-GUTIERREZ, Ruby. Low Thermal Conductivity Block from a Hybrid Geopolymer Concrete based on Fly Ash and other Industrial Wastes. TecnoL. [online]. 2024, vol.27, n.61, e203.  Epub 23-Dez-2024. ISSN 0123-7799.  https://doi.org/10.22430/22565337.3102.

The use of alternative cementitious materials and the use of industrial waste as supplementary materials or aggregates in the production of concrete and structural elements that guarantee good mechanical performance, reduced dead load, and high thermal comfort are in line with the principles of circular economy in the construction sector. Therefore, the objective of this research was to develop a hybrid cement based on alkaline activation with sodium sulfate (NS) of a mixture of fly ash (CV), silica fume (HS) and ordinary Portland cement (OPC), in proportions (CV+HS)/OPC of 70/30 %. The methodology used consisted of developing the hybrid cementitious material, which was classified as having moderate heat of hydration (MCH type), and subsequently using it, in proportions of 500 and 600 kg/m3, to produce structural concretes incorporating coarse recycled aggregates (AGR) and fine recycled aggregates (AFR) in the mixture, obtained from construction and demolition waste (CDW). The 600R concrete mixture reached a compressive strength of 18.9 MPa after 28 days of curing and reported a modulus of elasticity of 27 GPa. This concrete was validated in the production of perforated structural blocks, and to improve the thermal comfort of the concrete, 10 % and 20 % of the volume of recycled fine aggregate was replaced with recycled cork. The introduction of cork in the mixture, although it reduces the compressive strength of the block (29 %), allows to reduce the thermal conductivity by 32 %. Based on the results obtained, it is concluded that the use of 10 % of cork volume as a replacement for fine aggregate in the hybrid concrete mix allows the obtaining of a structural block with thermal comfort characteristics. The mixture considered optimal according to the results obtained was composed of 52.5 CV+17.5 HS+30 OPC, 4 % NS, 70 % AGR, 20 % AFR, and 10 % cork.

Palavras-chave : Geopolymer; fly ash; sodium sulfate; structural block; thermal conductivity.

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