Improving the Fire Resistance of Concrete Masonry Walls

Abstract

The purpose of this research was to understand the fire resistance of existing masonry construction and to identify ways to improve upon masonry's fire resistance. First, a literature review was conducted to determine the known effects fire had on concrete, and how this could change with different mix designs and temperature ranges. These included common mixes (such as normal-weight and lightweight concrete) as well as novel mixes (such as fly ash, recycled aggregate, or glass aggregate concrete). As masonry units have different geometries, research was also conducted to determine the effects different geometries have on the fire resistance of materials. Once this baseline was established, research was conducted on insulation materials, to determine which materials might be suitable and compatible with concrete masonry. Full scale experimental data was collected to determine how standard masonry units and building techniques reacted to the standard fire. Then new geometries and mix designs were tested to evaluate how the fire resistance was affected by these changes. After experimental data had been collected, thermal models were created to identify which masonry units could be tested in the future. Finally, novel concrete mixes were modeled and compared to determine their possible effect on the fire resistance of concrete masonry walls. The results showed that compartmentalisation of masonry blocks and walls improved the overall fire resistance, as heat flow through the hollow cells is the leading cause of insulation failure. Increasing the faceshell thickness or including insulation materials within the hollow cells improved the overall fire resistance. The data indicated that mortar joint types did not appear to have an impact on the insulation failure of masonry walls. Lightweight concrete mixes showed improved fire resistance when compared to normal weight concrete. Modeling results demonstrated that there are several new mix designs that can improve the thermal performance of masonry; however, with an increase in thermal performance there is usually a decrease in mechanical performance. The results of this research have helped establish a baseline for existing and novel masonry construction and provide recommendations iii for future study into improving the fire resistance of concrete masonry. iv I would like to thank the Canada Masonry Design Centre (CMDC) and the Canadian Masonry Producers Association (CCMPA) for their financial and in-kind support. I would especially like to extend my gratitude to Bennett Banting and David Stubbs for their personal involvement during my research. I would like to extend my gratitude to the Ottawa Fire Services OFS, especially Peter McBride and Sean Tracey, for their help with providing a location and support to continue my testing but more importantly their personal support and encouragment. I would like to thank the National Science and Engineering Research of Canada (NSERC), for their funding support. I would also like to thank Brendan Knapman from Rockwool for his time...