Time-Dependent Behavior of Full-Scale Recycled Aggregate Concrete Beams under Long-Term Loading
Wanlin Cao1, Yibin Liu1, Qiyun Qiao1
1College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China.
Materials (Basel, Switzerland)
|November 3, 2020
Summary
Recycled aggregate concrete (RAC) beams show increased deflection with higher recycled fine aggregate (RFA) content. Time-dependent behavior is influenced by RFAs and stress ratio, necessitating accurate deflection calculations for long-term loading.
Area of Science:
- Civil Engineering
- Materials Science
Background:
- Recycled aggregate concrete (RAC) is a sustainable construction material.
- Understanding its long-term performance under sustained loads is crucial for structural applications.
Purpose of the Study:
- To investigate the time-dependent behavior of RAC beams under long-term loading.
- To analyze the influence of recycled coarse aggregate (RCA) and recycled fine aggregate (RFA) replacement rates, concrete strength, and stress ratio on deflection and stiffness.
Main Methods:
- Casting and testing of sixteen full-scale RAC beams.
- Systematic variation of RCA and RFA replacement rates, concrete strength, and applied stress ratios.
- Monitoring deflection and stiffness over time under sustained loading.
Main Results:
- Increased deflection observed with higher RCA content at low stress ratios.
- Nonlinear creep and significant deflection increases (up to 30%) noted with 100% RFA replacement at high stress ratios.
- Concrete strength had minimal impact, while stress ratio affected initial deflection.
Conclusions:
- Recycled aggregate properties, particularly RFAs, significantly impact the time-dependent deflection of RAC beams.
- A new deflection calculation formula for RAC under long-term loading was developed and validated against experimental data.
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