Laboratory dilatometry and field test to assess durability of masonry

Abstract

This article analyses the use of dilatometry to assess the durability of load-bearing clay brick masonry in a century home in Toronto (Canada). The building had recently undergone the addition of medium density closed-cell polyurethane spray-applied foam insulation on all interior sides of the exterior clay brick load-bearing walls, increasing the insulating value in areas to RSI 7.9 m2K/W, on average, from the original RSI 0.5 m2K/W, on average. The critical moisture content (saturation degree) of representative samples from the building were compared with values obtained from frost dilatometry testing. The later indicate critical moisture content for freeze–thaw. The frost dilatometry method was furthered by studying three-dimensional testing, rather than the traditional two-dimensional approach. The results showed the brick masonry in the study building are at a relatively low risk of freeze–thaw damage thanks to good resistance of freeze–thaw of the subject brick masonry and low wetting potential of the brick masonry on site. This further strengthens the need for good water shedding characteristics.

On interior rehabilitation of buildings with historic facades

“…Thus, the CMC is established either by dilatometry (Vuorinen, 1969; Williams and Richman, in press) or by measuring residual dynamic modulus (Bomberg and Shirtliffe, 2009) when under one cycle of freeze-thaw the condition of “discontinuity” in material is reached, that is, damage propagate without addition of any additional energy. This state, as shown in the works of Fagerlund (1973, 1974) and others, may be reached either by a multitude of cycles, each of them increasing moisture content in the material, or by one cycle if the moisture is already at the critical level when the freeze-thaw has been started.…”