Estudo do desempenho térmico e mecânico em argamassas de revestimento com substituição do agregado natural pela vermiculita expandida

Abstract

Interest in the thermal performance of buildings is increasingly common due to user requirements and improvements in the enforcement of performance standards, which set the minimum efficiency criteria for a building. We highlight the charges related to thermal behavior, because they impact on the construction, the environment and affect the comfort and costs to users. An alternative to solve this problem is to change the constituent materials of building systems, such as the use of lightweight aggregates with potential for thermal insulation. In this context, the objective of the present work is to analyze the thermal and mechanical performance of coating mortars with substitution of natural aggregate for expanded vermiculite. The experimental procedure began with the characterization of the materials and the production of mortars with a 1: 1: 6 volume trace (cement: lime: sand) with substitutions of 25, 30, 35, 40, 45 and 50% of natural sand by expanded vermiculite, then fresh tests (consistency, density and water retention), hardened tests (density, tensile and compressive strength, modulus of elasticity, capillary and dip absorption and adhesion resistance) and finally , the thermal tests with the KD2Pro appliance and the thermal performance, through a prototype simulating the incidence of heat in a wall. The results show that the workability was improved according to the incorporation of expanded vermiculite, the density in the fresh and hardened state was reduced, the compressive strength decreased slightly, the void index and the bond strength increased. All sealing systems with ceramic bricks coated by the mortars under analysis met the requirements established by NBR 15575 (ANBT, 2013). The thermal performance evaluated by the prototype showed an improvement in thermal insulation according to the incorporation of expanded vermiculite, obtaining more significant results for mortars with 45 and 50% substitution, which came to isolate 34 ° C and 40 ° C, respectively. Therefore, the expansion of expanded vermiculite in cement mortars is able to benefit from thermal insulation without causing major damage to other mortar properties, making it a product with good thermal and mechanical performance.