Influence of type of mortar and unit in the flexural strength parallel to the bed-joints of brick-mortar assemblages

According to EN 1996 Part 1-1, the flexural strength of masonry could be estimated based on information related mainly to the compressive strength of the mortar and the type of material of the unit. However, it is necessary to consider the impact of the interaction between components due to their physical characteristics, such as water absorption of the units and water retentivity of the mortar that may affect the bond between masonry components. Therefore, this paper evaluates the influence of the use of different types of mortar and units on the flexural strength parallel to the joints of masonry. For this, two types of mortar were considered: 1:1:6, and 1:0:5 (Cement: Lime: Sand), by volume. Regarding the units, two types of clay bricks of different geometric configuration (solid and frogged) were chosen. Thus, four combinations of units and mortar types were considered for the construction of the masonry wallets according to the guidelines indicated in EN1052-2. Flexural strength parallel to the bed-joints was tested according to EN1052-2, and compressive strengths of mortar specimens were controlled in accordance with EN1015-11 for the age of 90 days. In addition, characteristics of the units and water retentivity of mortars were also evaluated. The results showed that the compressive strength of the mortar is a significant factor if the failure occurs at the mortar bed-joint and not at the interface between components.