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Effectiveness of Strengthening RC Beams Using Composite Materials-An Accelerated Strengthening Method
Dorota Michałowska-Maziejuk1, Barbara Goszczyńska1
1Faculty of Civil Engineering and Architecture, Department of Strength Materials and Building Structures, Kielce University of Technology, al. Tysiąclecia Państwa Polskiego 7, 25-314 Kielce, Poland.
Materials (Basel, Switzerland)
|July 14, 2023
Summary
Accelerated strengthening of concrete beams using carbon fiber strips is feasible. Heating the strips significantly boosts strengthening efficiency and reduces execution time from 7 days to 1.5 hours.
Area of Science:
- Civil Engineering
- Materials Science
Background:
- Reinforced concrete beams often require strengthening due to degradation or increased load demands.
- The NSM (Near-Surface Mounted) method using carbon fiber reinforced polymer (CFRP) strips is a common strengthening technique.
- Standard adhesive bonding for CFRP strips requires a lengthy curing period.
Purpose of the Study:
- To analyze the effectiveness of strengthening preloaded reinforced concrete beams using CFRP strips applied via the NSM method.
- To investigate the impact of accelerated adhesive curing through strip heating on strengthening efficiency.
- To determine the optimal heating temperature for maximizing strengthening levels under sustained loading.
Main Methods:
- Testing of preloaded reinforced concrete beams strengthened with CFRP strips using the NSM method.
- Application of thixotropic epoxy resin adhesive for bonding.
- Utilizing a prototype heating device to accelerate the adhesive curing process.
- Evaluation of strengthening effectiveness under sustained load conditions simulating real-world scenarios.
Main Results:
- Accelerated strengthening through strip heating is feasible and effective.
- Heating significantly reduced adhesive cure time from 7 days to 1.5 hours.
- Higher strengthening efficiency was achieved with the accelerated method, with optimal heating temperature identified.
Conclusions:
- Strip heating offers a viable method to accelerate CFRP strengthening of reinforced concrete beams.
- The accelerated NSM strengthening method significantly reduces project timelines while enhancing efficiency.
- Further analysis considered the influence of steel and composite reinforcement ratios on strengthening outcomes.
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