Masonry has been widely used as a construction method. However, there is a lack of information on its fire behavior due to the multitude of variables that could influence this method. This paper aimed to identify the influence of loading and mortar coating thickness on the fire behavior of masonry. Hence, six masonries made of clay tiles laid with mortar were evaluated. The mortar coating had a thickness of 25 mm on the face not exposed to high temperatures, while the fire-exposed face had thicknesses of 0, 15, and 25 mm. For each mortar coating thickness, two specimens were tested, with and without loading of 10 tf/m. The real-scale specimens were subjected to the standard ISO 834 fire curve for four hours, during which the properties of stability, airtightness, and thermal insulation were assessed. Results showed that loaded specimens yielded smaller deformations than unloaded ones. Samples that lacked mortar coating on the fire-exposed face underwent fire resistance decrease of 27.5%, while the ones with 15 mm decreased by 58.1%, and the ones with 25 mm decreased by 41.0%. As mortar coating thickness increased, the plane deformations decreased from 40 mm to 29 mm and the thermal insulation properties of the walls improved significantly. For specimens with mortar coating thickness of 25 mm, the load application resulted in a reduction of 23.8% of the thermal insulation, while the unloaded specimen showed a decrease of 43.3%, as well as a modification of its fire-resistance rating.
Concrete structures have become common all over the world, however the mateiral undergoes a cracking process, allowing the entrance of deleterious agents. Some countries are now spending more money on recovering existing structures than on building new ones. Thus, in the last decade, researchers have evaluated techniques to promote the selfhealing of concrete. It is known that the concrete has a small healing capacity due to the late hydration of anhydrous cement partickes, but it is limited to small cracks and it increases the consumption of cement, which generates financial and environmental disadvantages. In the search for more promising techniques, it has been studied the use of bacteria for the production of biominerals, which heal the cracks, reduce the permeability and the water absorption, and increase the compressive strenght. This study aims to present the state-ofart of this technique, approaching the species used and the methodology of insertion of the microorganisms in the concrete matrix. Among the taxonomic genus studied, there are advantages in the use of bactéria of the genus Bacillus, because they have physiology resistant to aggressive environments. As for the insertion of the bacteria in the concrete, advantages and disadvantages are presented in relation to their encapsulation in lightweight aggregates and their direct addition in the kneading water of the concrete. Gaps were still to be studied, such as the reduction of costs involved in the preparation of the material, improvement of design methodologies, simplification of the construction processes, verification of the durability of this concrete, and study of the inactive life in the bactéria within the hardened concrete.
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