Evaluation of the Physical and Mechanical Properties of Autoclaved and Foamed Concrete Blocks Marketed in Passo Fundo/RS Brazil

Resumen

Cellular concrete is a light concrete that differs from others because of the presence of air voids (porosity) within the mortars. This air voids, formed by air bubbles, influences the behavior of such concrete. Cellular concrete blocks have been gaining market due to their characteristics which include thermal and acoustic insulation, and low density. However, properties, such as their low compressive strength limit the application of using this type of material, for example, use on structural walls (walls that may be subjected to imposed deformations or more significant occupancy loads), which require a minimum compressive strength of 3 MPa. Moreover, they should meet the minimum compressive strength required by the standard. Therefore, this paper sets out to evaluate the physical and mechanical properties of two types of cellular blocks commercialized in the region of Passo Fundo/RS, Brazil. Experimental assays were performed to determine the following properties: dry density, wet density, air voids, water absorption, thermal conductivity and compressive strength. The results showed that the autoclaved cellular concrete had better physical and mechanical properties when compared to the foamed cellular concrete, i.e., the autoclaved cellular concrete block had a higher compressive strength, lower thermal conductivity, lower density and its pores were more homogeneously distributed. However, the values found for the compressive strength of both blocks were lower than those determined by the manufacturers of these blocks. Therefore, autoclaved concrete blocks can be used for sealing masonry in buildings as it has achieved minimum compressive strength required for this type of wall. On the other hand, foamed concrete blocks, on average, presented values of compressive strength much lower (0.6 MPa) than values required for sealing masonry walls (1.5 MPa), requiring the manufacturer to review the trace formulation of these blocks.