Dimensional Stability of Masonry Walls: Fid-Bau Portal

Dimensional Stability of Masonry Walls

J. R. Clifton / B. E. Foster / E. Trattner / R. A. Clevenger

To assess the contribution of dolomitic limes to dimensional stability of masonry construction, 65 brick masonry walls, 34 by 40 by 8 in. (0.86 by 1.0 by 0.20 m), were constructed. The program involved the following design variables: 6 hydrated limes ranging in autoclave expansion from 0.10 to 15.1 percent; 2 types of brick, one with high water absorption and insignificant autoclave expansion; and, 2 mortars of cement:lime:sand proportions of 1:1:6 and 1:2:9 by volume. Half of the walls were subjected to temperature and moisture cycles, performed indoors, for 3 1/2 years; the other half were tested outdoors for 14 years. Half of the indoor and outdoor exposed walls were spring loaded at 25 psi 170,000 N/sq m. Observed expansion of the walls was found to be related to the potential expansions (as measured by the autoclave test) of the limes. The largest wall expansion took place with the following combination: high potential expansive lime; stable, low absorption brick; unloaded wall; and, 14 year outdoor exposure. In the 14-year outdoor exposure, loss of bond and resulting damage from freezing were complicating factors. The effects of lime, mortar mix, brick, loading, and exposure on the dimensional instability of the masonry walls are discussed.