Volume 4, Issue 1 (January 2007)
The Effect of Void Area on Brick Masonry Performance
Higher void (hollow) brick offer the potential for energy savings, decreased raw material usage and reduced environmental impact. These advantages are related to the movement toward “green” building materials. The National Brick Research Center has performed an extensive study comparing the wall system performance of hollow and solid brick. Hollow masonry units are defined by ASTM C 652 while solid masonry units are specified in ASTM C 216. The key differences between these two specifications are related to the permissible void area and face shell thickness. The objective of this work was to determine what effect, if any, increasing void area might have on important aspects of the performance of brick masonry. The effect of decreasing face shell thickness was also evaluated. For this study, the performance of several sets of comparison extruded brick was measured. These sets of comparison brick represent a range of manufacturers and, thus, a range of physical properties. Water penetration, flexural bond strength, and compressive strength were measured on each type of brick and used as indicators of potential performance in a wall. Additionally, mortar usage as a function of void area was studied. Based on the results of testing from these sets of comparison brick, increasing void area or decreasing face shell thickness did not result in increased water penetration or decreased flexural bond strength.