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Eurocode Shear Design of Coarse Recycled Aggregate Concrete: Reliability Analysis and Partial Factor Calibration
João Pacheco1, Jorge de Brito1, Carlos Chastre2
1CERIS, IST, Universidade de Lisboa, 1049-001 Lisbon, Portugal.
Materials (Basel, Switzerland)
|August 7, 2021
Summary
This study proposes design partial factors for recycled aggregate concrete (RAC) to ensure structural safety. Calibrated reliability analyses show reduced shear resistance for RAC compared to natural aggregate concrete, necessitating specific design clauses.
Area of Science:
- Civil Engineering
- Materials Science
- Structural Engineering
Background:
- Recycled aggregate concrete (RAC) faces skepticism due to aggregate heterogeneity impacting concrete behavior.
- Previous research indicated higher model uncertainty for RAC shear design compared to natural aggregate concrete (NAC).
- A need exists for specific design factors to ensure the safety of RAC structures.
Purpose of the Study:
- To define design clauses for coarse recycled aggregate concrete.
- To propose partial factors for shear failure design of RAC using structural reliability concepts.
- To address the uncertainty in RAC behavior by establishing reliable design parameters.
Main Methods:
- Utilized structural reliability concepts for calibration of partial factors.
- Conducted explicit reliability analyses for different design scenarios (beams with shear reinforcement, slabs without).
- Compared model uncertainty statistics of RAC elements against NAC elements.
Main Results:
- Calibrated partial factors for RAC shear design are presented.
- For elements without shear reinforcement, RAC shear resistance is reduced by 10% (EN1992) or 15% (prEN1992) compared to NAC.
- For elements with shear reinforcement, RAC shear resistance is reduced by 5%, with potential reductions up to 20% under pessimistic assumptions.
Conclusions:
- Proposed partial factors enhance the safe design of recycled aggregate concrete.
- The findings support the incorporation of coarse recycled concrete aggregates into structural design.
- Specific design clauses are necessary to account for the reduced shear resistance of RAC.
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