Using IRA Brick Halifax NS
Using IRA Brick
Source: MASONRY CONSTRUCTION MAGAZINE
Publication date: April 1, 2004
I have heard that if you use brick with a very low IRA in masonry walls, they will float on the mortar during construction, which results in later water leakage problems.
Is this a common problem? If so, which IRA brick should not be used in masonry walls?
Masonry walls built using brick units with a low Initial Rate of Absorption (IRA) often have lower bond strength than walls built with moderate IRA units because very little water is available to be absorbed into the unit during installation into the wall. absorption There is little mechanical bonding without water absorption, which often results in lower bond strength. Because little water is absorbed, little paste is absorbed, which limits chemical bonding.
Using mortars with higher cement content often significantly increases bond strength. However, as the cement content of mortar goes up, there is an increase in the rate of mortar shrinkage. High shrinkage can result in cracking of the mortar, which increases water penetration.
When it pertains to low IRA brick, if a particular combination of mortar and brick has relatively low bond strength, it does not necessarily mean that the rate of water penetration is correspondingly increased. In fact, some studies suggest that low IRA brick may actually out perform brick of a mid-range IRA in resisting water penetration.
In research performed by J. Gregg Borchelt and J. A. Tann, which is summa...