Influência das características da base na resistência de aderência à tração e na distribuição de poros de uma argamassa

Abstract

The difference on properties of a mortar when applied on substrata with distinct characteristics was studied. Twelve masonry miniwalls were elaborated, on which was applied an industrialized mortar, classified according to ABNT-NBR 13281/95 as II - High - C. The study variables were the type of substratum (ceramic block, concrete block and brick), variation in the preparation of the substratum (with and without mortar) and age (7 and 28 days). The characterization of the mortar (consistency, compressive strength and distribution of pores), of substrata (compressive strength, water suction, absorption, and distribution of pores) and of the mortar applied on each substratum (tack resistance, distribution of pores in the hard mortar and visual analysis with microscope use) were carried out. The main conclusions were that the used substrata presented different physical properties, evidenced by a noticeable difference in the distribution of the pores, compressive strength and water absorption. It was also observed that the distribution of pores of the hard mortar is modified in function of the type of substratum, as well as the tack resistance to the traction of the mortar. The chapisco used modified the distribution of pores of the mortar, and also propitiated an increase in the tack resistance to traction in two types of substratum.

Key words: mortar, pore size distribution, tack resistance to traction, durability.