HMC08 - 1st Historical Mortars Conference: Characterization, Diagnosis, Conservation, Repair and Compatibilit, LNEC, Lisbon, 24-26 September 2008Lime mortars with brick dust and grounded particles have been largely used in
many regions of the world as plasters, renders and in masonry joints and repointing. In
Portugal this type of pozzolanic mortars has been introduced at least since the Roman
period, particularly when hydraulic characteristics were needed. Brick dust, a source of
silica and also of alumina, react with the calcium hydroxide of the lime, resulting on
silicates and aluminates of calcium hydrates. The brick particles (grounded to appropriate
dimensions) will act as a specific aggregate.
The lime mortars with brick material are supposed to achieve hydraulic characteristics and
increment their mechanical resistances and durability, compared to pure lime mortars. Also
the mortar behavior in face of water (liquid and vapor) will be changed. Lime mortars with
brick material also present compatibility with ancient supports, what does not happened
with cement mortars.
Within this context and associating the improvement of mortars characteristics to the
necessity of sustainable construction practices, some mortars formulated with lime and the
addition of industrial by-products have been recently studied by several researchers. To
present pozzolanic reactivity, the brick material should be in an amorphous form, obtained
from a low thermal industrial process. It also should be finely grounded, so that there is a
big surface of pozzolanic particles to react.
The aim of this work is to present the evaluation of the influence of brick dust and of brick
particles in lime mortars. Characteristics, particularly in terms of flexural and compressive
resistances, capillary water absorption and water vapor permeability will be discussed. The
repair mortars requirements of compatibility with the ancient masonries and their
protection will be analyzed.
Considering the increase of some characteristics revealed by some mortars with brick dust
and with brick particles, when compared with a pure lime mortar, it is possible to evaluate
the benefits of the addition of this type of pozzolan and aggregates in lime mortars, and the
viability of this industrial by-product reutilization
