Mecânica da fratura não linear aplicada ao estudo do concreto

Abstract

With the continuous growth of the construction industry, the search for innovative materials has increasingly required research and studies for their implementation in the job market. The study of more durable concretes contributes to the construction of stronger and more sustainable infrastructures, reducing repair costs and increasing the safety of buildings and public works in the country. In order to promote greater durability of building structures and concrete elements for infrastructure and large-scale works, the use of special concretes, such as Self-Compacting Concrete (SCC), has also become a very promising alternative in the construction market. Thus, this study aims to evaluate the mechanical properties and cracking resistance of concrete elements, on a reduced scale, through three-point bending tests. For this purpose, experimental analyses were carried out based on the results obtained using the CMOD (Crack Mouth Opening Displacement) system, which allows the collection of load versus displacement curves using a clip-gage installed in pre-existing and controlled notches on the bottom face of the specimens, enabling accurate measurement of crack openings. The testing program involved the investigation of four types of concrete: Conventional Concrete (CC), Conventional Concrete Reinforced with PVA (Polyvinyl Alcohol) Fibers (CCVRFP), Self-Compacting Concrete (SCC), and Self-Compacting Concrete Reinforced with PVA Fibers (SCCVRFP), the latter developed with the incorporation of waste materials into the mix. The results show that self-compacting concrete (SCC), even without the addition of fibers, outperformed conventional concrete (CC). Notably, an increase of nearly 25% in the initial cracking resistance was observed. This indicates better matrix cohesion and improved mechanical response in relation to the formation of the first crack. This research is expected to contribute to the selection of sustainable and efficient materials, combining the addition of waste and fibers with enhanced structural performance suitable for the demands of such infrastructures.