Tratamento superficial para Blocos de Terra Comprimida (BTC): avaliação do potencial da mucilagem de xique-xique (Pilosocereus gounellei)

Abstract

Sustainable architecture or bio-architecture, with emphasis on buildings on raw earth, present an environmental advantage that makes them extremely competitive due to their thermal and hygrothermal properties that contribute to the regulation of the thermal comfort of environments, and to the exploitation of mechanisms with bioclimatic functioning, providing even more salubrious environments. However, one of the main problems of these constructions is related to the performance against the action of the rain water, caused by the appearance of pathologies. Faced with such considerations, the present work proposes the use of the mucilage of xique-xique cactus (Pilosocereus gounellei), as a surface treatment for compressed earth blocks (CEB), in order to verify its potential as a protective film. Tests with different mucilage concentrations and at different sample scales, such as cubic specimens, small walls and full-scale prototypes, were performed comparing the proposed material (TX) with a commercial acrylic waterproofing resin (TR) and untreated control samples (TC). Based on the results, it was observed that the TX treatment obtained a satisfactory performance in the tests of water absorption by capillarity, being very similar to the TR treatment, having in view that at 60 minutes of test the samples TR, TX and TC had an addition of mass of 0.3 g/cm², 0.5 g/cm² and 1.4 g/cm², respectively. The water vapor permeability at TX was 8% higher compared to TR and 6% lower than TC, demonstrating a superior behavior of the samples with mucilage when compared to the samples with resin treatment. Regarding durability after heat and thermal shock tests, the TX samples also had satisfactory performance. Therefore, it can be concluded that the mucilage of xique-xique has potential for use as a surface waterproofing treatment in CEB blocks and possibly in other types of raw earth construction. This work has provided for the filing of an invention patent under the title: Process and waterproofing product based on cactus mucilage (BR 10 2019 008108 2).