Thesis supervisor: Éva Eszter Majorosné Lublóy
Location of studies (in Hungarian): Department of Construction Materials and Technologies Abbreviation of location of studies: EOEM
Description of the research topic:
In the case of reinforced concrete structures, the compressive strength of concrete and the tensile strength of steel reinforcements decrease during a fire, which can result in plastic deformations. However, the decrease in load-bearing capacity of the structure is greatly influenced by the change in the interaction (bond strength) between the concrete and the steel reinforcements. The change in the interaction between concrete and steel not only affects the load-bearing capacity, but also influences the way cracks form and develop.
Designing and constructing reinforced concrete structures involves an important question of how and to what extent the connection between the two materials changes under high temperatures.
Part of the bond between the concrete and the reinforcing steel is determined by a chemical bond between the two materials. The level of chemical bonding can be modified by altering the concrete composition, such as by adding supplementary materials (blast furnace slag, fly ash, silica fume, metakaolin). In addition to modifying the chemical bond, the concrete strength, which provides the other part of the bond through mechanical connection, can also be modified by the concrete composition (supplementary materials).
The adhesive strength significantly decreases at a temperature of 400°C for both ribbed and smooth reinforcing steel, making it impossible to ensure safe anchoring of the reinforcing steel within the structure.
The aim of this research is to clarify how and to what extent the bond strength changes due to the addition of different supplementary materials.
Before starting the measurements, the candidate must review the relevant literature and determine the parameters of the laboratory tests based on this. To clarify the issue, the candidate must perform laboratory tests, which include the expected strength tests (compressive strength, adhesive strength), macro (visual inspection, optical microscope), and microstructure (SEM) analysis, as well as realizing the engineering correlations.
Based on the measurement results, the critical anchoring length and the corresponding temperature can be determined, and recommendations can be made for modifying the design standards.
Deadline for application: 2024-05-31
2024. IV. 17. ODT ülés Az ODT következő ülésére 2024. június 14-én, pénteken 10.00 órakor kerül sor a Semmelweis Egyetem Szenátusi termében (Bp. Üllői út 26. I. emelet).
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