Desenvolvimento de argamassa termoisolante para revestimento de paredes de alvenaria em edificações com uso de areia de britagem e vermiculita

Abstract

Throughout their life cycle, buildings consume electrical energy with air conditioning equipment. The growing global concern about the efficient use of natural resources and the climate crisis imply the adoption of public policies and construction strategies that make buildings more efficient in terms of thermal performance. The present work aims to develop cement rendering mortars with low thermal conductivity walls, composed of crushed sand from the Juiz de Fora-MG region and expanded vermiculite. A reference cement and sand mortar was studied in a 1:6 volume ratio and three mortars with replacement levels of with and without air-entraining additive (0.035% of the cement mass). In order to characterize the mortars produced, mechanical resistance tests, water absorption by capillarity, dynamic modulus of elasticity, density and thermal conductivity were carried out in experimental equipment, developed at the Federal University of Juiz de Fora, with results validated by a commercial equipment. Using computer simulation, energy savings were evaluated wi - RJ, with a hot climate, and São Joaquim-RS, with a cold climate. The V30A mortar – 30% vermiculite and additive – showed the greatest reductions in the values of compressive strength (59%), tensile strength (33%), thermal conductivity (61%) and dynamic modulus of elasticity (72%), in relation to the reference mortar, without vermiculite and additives. The annual energy savings obtained with the use of V30A mortar in the building envelope analyzed in relation to the simulation with conventional mortar was 3.15% for Rio de Janeiro (bioclimatic zone 8) and 4.90% for São Joaquim ( bioclimatic zone 1). It is concluded that the use of vermiculite is effective in reducing the thermal conductivity of the mortars studied, but its use in coatings must be combined with other construction solutions – roofing, for example – for the most important thermal performance of buildings.