Effect of replacing natural sand with high levels of expanded vermiculite on the thermal and mechanical properties of coating mortars

I.M.S.  Barros; K. C.  Cabral; J.A.  Silva Neto; M.A.S. Anjos; R.A.  Araújo; F.L.M.  Rocha; G.M.  Nunes

doi:10.3989/mc.2025.392924

Authors

I.M.S. Barros Federal University of Rio Grande do Norte, UFRN - Federal University of Paraíba, UFPB https://orcid.org/0000-0002-8719-6055
K. C. Cabral Federal University of Rio Grande do Norte, UFRN https://orcid.org/0000-0001-7502-3002
J.A. Silva Neto Federal University of Paraíba, UFPB https://orcid.org/0000-0002-8355-1902
M.A.S. Anjos Federal University of Rio Grande do Norte, UFRN https://orcid.org/0000-0001-9563-2534
R.A. Araújo Federal University of Rio Grande do Norte, UFRN https://orcid.org/0000-0001-9265-9459
F.L.M. Rocha Federal University of Paraíba, UFPB https://orcid.org/0000-0002-0707-9140
G.M. Nunes Federal University of Paraíba, UFPB https://orcid.org/0000-0002-5519-3714

DOI:

https://doi.org/10.3989/mc.2025.392924

Keywords:

Expanded Vermiculite., Mortars, Coatings, Thermo-mechanical performance

Abstract

Coating mortars must have properties that guarantee good performance in construction. Expanded vermiculite, as a substitute for fine aggregate, reduces thermal conductivity, specific mass and mechanical strength, which requires studying the levels of substitution. This study evaluated 1:1:6 mortars (cement:lime:aggregate) with a vermiculite replacement between 25% and 100%. Tests were carried out to evaluate energy efficiency, thermal conductivity, diffusivity, density, porosity and compressive and tensile strength. The results showed that mortars with a vermiculite replacement of 25% and 50% offered the best balance between thermal and mechanical properties, being suitable as coatings to improve thermal performance without compromising mechanical strength.

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