Examining the behavior of concrete masonry units under fire and post‐fire conditions

Abstract

Masonry is an inert construction material with favorable thermal and mechanical properties. While masonry is widely used in buildings, the fire performance of this material has not received much attention over the years. This continues to hinder the understanding of the fire behavior of masonry. To bridge this knowledge gap, this study presents the results of an experimental campaign carried out on concrete masonry blocks (CMUs) to investigate fire-induced degradation of the compressive strength of CMUs under elevated temperatures and post-fire conditions. In this campaign, steady-state tests were conducted; wherein standard-sized CMUs are exposed to a heating scenario ranging from 25 to 800 C followed by cooling to ambient temperature. In addition, these tests were also complimented with a thermogravimetric (TGA) analysis to arrive at a comprehensive understanding of the degradation of the strength property of masonry. Results from the tests clearly show that the degradation in CMUs is lower than that typically observed in normal strength concrete. Furthermore, our findings also infer that masonry is capable of retaining a larger percentage of strength when tested under post-fire conditions as opposed to being under heating.

Residual mechanical resistance of concrete blocks and laying mortars after high temperatures

“…Daware et al 8 evaluated concrete half blocks produced with lightweight aggregates, heated at a rate of 3.3 C/min to temperatures from 200 C to 800 C. Specimens were kept at the maximum temperature for 3 h. Compression tests were performed after cooling slowly in the oven and on hot specimens. The strength at higher temperatures was higher than the residual strength after cooling.…”