Thermal performance of sisal fiber-cement roofing tiles for rural constructions

Gustavo Henrique Denzin Tonoli,Sérgio Francisco Dos Santos,Wilson Nunes Dos Santos,José Antonio Rabi,Holmer Savastano Junior

doi:10.1590/s0103-90162011000100001

Gustavo Henrique Denzin Tonoli, Sérgio Francisco Dos Santos + Show 3 more

Open Access

https://doi.org/10.1590/s0103-90162011000100001

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Abstract

Roofing provides the main protection against direct solar radiation in animal housing. Appropriate thermal properties of roofing materials tend to improve the thermal comfort in the inner ambient. Nonasbestos fiber-cement roofing components reinforced with cellulose pulp from sisal (Agave sisalana) were produced by slurry and dewatering techniques, with an optional addition of polypropylene fibers. Nonasbestos tiles were evaluated and compared with commercially available asbestos-cement sheets and ceramic tiles (frequently chosen as roofing materials for animal housing). Thermal conductivity and thermal diffusivity of tiles were determined by the parallel hot-wire method, along with the evaluation of the downside surface temperature. Cement-based components reinforced with sisal pulp presented better thermal performance at room temperature (25ºC), while those reinforced with sisal pulp added by polypropylene fibers presented better thermal performance at 60ºC. Non-asbestos cement tiles provided more efficient protection against radiation than asbestos corrugated sheets.

Highlights

Despite the concerns about the asbestos banishment, asbestos-cement corrugated sheets are claimed as the cheapest alternative for roofing in Brazil (Conceição et al, 2008)
Vegetable fibers added to cement roofing tiles enhance the thermal insulation in comparison to asbestos-cement tiles, specially due to their higher porosity and to air incorporation into the composite (Roma Jr. et al, 2008)
Sisal and sisal+PP fiber-cement presented higher water absorption (WA) and apparent void volume (AVV) than asbestos-cement and ceramic (Figure 5a) due to the air trapped by sisal pulp and/or PP fibers

Summary

Introduction

Despite the concerns about the asbestos banishment, asbestos-cement corrugated sheets are claimed as the cheapest alternative for roofing in Brazil (Conceição et al, 2008). Studies on thermal comfort rendered by roofing tiles reinforced with vegetable fibers were carried out by Kawabata et al (2005) and Roma Jr. et al (2008). Vegetable fibers added to cement roofing tiles enhance the thermal insulation in comparison to asbestos-cement tiles, specially due to their higher porosity and to air incorporation into the composite (Roma Jr. et al, 2008). Roofing is the building component that contributes most to the indoor environment and to the corresponding thermal comfort assessment with regard to animal housing (Conceição et al, 2008). To keep their homeothermy, animals rely on thermoregulatory mechanisms that may lead to physiological compensations in detriment of production (Grant and Albright, 1995). As far as human thermal comfort is concerned, a similar motivation has been attempted in

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