RAEng Frontiers Champion Project: Recycled Aggregate in South East Asia

DESIGN STRATEGY FOR RECYCLED AGGREGATE CONCRETE Nikola Tošić Universitat Politécnica de Catalunya [email protected] CONTENTS

▸ Intro to CEN prEN1992 and fib Model Code 2020

▸ RAC provisions in prEN1992 and MC2020

▸ Background to RAC code provisions

▸ Implications for design and future work 1. Intro to CEN prEN1992 & fib MC2020 Intro to prEN1992 and MC2020

CEN – European Committee for Standardization

EU + Iceland + Norway + Switzerland + UK + North Macedonia + + Serbia + Turkey Intro to prEN1992 and MC2020

EN 1992 – Design of Concrete Structures EN 1992-1-1:2004 Part 1-1: General rules and rules for buildings EN 1992-1-2:2004 Part 1-2: General rules - Structural fire design EN 1992-2:2005 Part 2: Concrete bridges - Design and detailing rules EN 1992-3:2006 Part 3: Liquid retaining and containment structures

Links to other EN standards: EN 196, EN 197 – Methods of testing ; Cement EN 206+A1 – Concrete – Part 1: Specification, performance, production and conformity EN 10080 – Steel for the reinforcement of concrete EN 12620 – Aggregates for concrete EN 13670 – Execution of concrete structures Intro to prEN1992 and MC2020

Revision of the Intro to prEN1992 and MC2020

Revision of the Eurocodes

https://eurocodes.jrc.ec.europa.eu/showpage.php?id=23 Intro to prEN1992 and MC2020

Revision of the Eurocodes: prEN1992-1-1 & prEN1992-1-2

▸ CEN Enquiry: September–December 2021

▸ Target date of availability of 2nd generation EN 1992: March 2023

▸ Date of publication – national choice (National Annexes!)

▸ Target Date of Availability of last 2nd gen. Eurocodes: March 2026

▸ Target Date of Withdrawal of 1st gen Eurocodes: March 2028 Intro to prEN1992 and MC2020

International Federation for Structural Concrete – fib

Euro-International Committee for Concrete CEB Comité euro-internationale du béton 1953 fib International Federation for Prestressing Fédération internationale de la précontrainte 1952 David Fernández-Ordóñez, 2018 Intro to prEN1992 and MC2020

International Federation for Structural Concrete – fib

David Fernández-Ordóñez, 2018 Intro to prEN1992 and MC2020

Evolution of Model Codes

David Fernández-Ordóñez, 2018 Intro to prEN1992 and MC2020

Task Group 4.7: Structural Applications of Recycled Aggregate Concrete – Properties, Modelling, and Design

https://www.fib-international.org/commissions/com4-concrete-concrete-technology.html 2. RAC provisions in prEN1992 & fib MC2020 RAC provisions in prEN1992 and MC2020

Current basis: EN 12620 & EN 206+A1 https://www.gov.il/BlobFolder/reports/aggregates/en/04%20Sanchez- %20EN%2012620%20Aggregates%20for%20concrete.pdf

▸ Only coarse RA ▸ Composition-based classification ▸ Future – performance-based classification? RAC provisions in prEN1992 and MC2020

Current basis: EN 12620 & EN 206+A1

▸ Only coarse RA ▸ Low substitution ratios ▸ Assuming no change in properties/not taking into account any change RAC provisions in prEN1992 and MC2020

Current situation:

[1]

▸ “High collection rates of well-segregated CDW are achieved… but the market uptake of recycled materials is really low; large storage areas at treatment plants have essentially become temporary landfills” [2]

▸ Motivation: increase the use of RA in structural applications! RAC provisions in prEN1992 and MC2020 RAC provisions in prEN1992 and MC2020 RAC provisions in prEN1992 and MC2020

MC2020 section 12 3. Background to RAC code provisions RAC provisions in prEN1992 and MC2020

Background: significant amount of research performed over previous decades on all levels – from material to structural [3]

[6]

[5] [7]

[4] RAC provisions in prEN1992 and MC2020

Background documents

Fabienne Robert, 2021 RAC provisions in prEN1992 and MC2020

Choice of main variable – N.3

▸ Definition of αRA ▸ Future: changes to EN 206?

▸ Future: LoA with more variables?

[8] RAC provisions in prEN1992 and MC2020

Choice of main variable – MC2020

▸ τTRA (=αRA) and τRCA ▸ MC2020 does not rely on EN 206 RAC provisions in prEN1992 and MC2020

Density • volumetric vs. mass replacement ratio

Δ휌RAC = 휌ag ∙ 푉ag − 휌ag ∙ 푉ag ∙ 1 − 훼V,RA + 휌c ∙ 푉ag ∙ 훼V,RA = (휌c−휌ag) ∙ 푉ag ∙ 훼V,RA

휌c ∙ 푉ag ∙ 훼V,RA 휌c ∙ 훼V,RA 훼RA = = 휌ag ∙ 푉ag 1 − 훼V,RA + 휌c ∙ 푉ag ∙ 훼V,RA 휌ag ∙ 1 − 훼V,RA + 휌c ∙ 훼V,RA

휌ag ∙ 훼RA 훼V,RA = 휌c + (휌ag − 휌c) ∙ 훼RA

휌RAC = 2.50 − 0.22 ∙ 훼RA [9] RAC provisions in prEN1992 and MC2020

Compressive strength • Input parameter in the code! • No observed difference in statistical distribution vs. NAC

• <= C50/60 (~fcm,max = 60 MPa)

[10] RAC provisions in prEN1992 and MC2020

Modulus of elasticity

1Τ3 • 퐸cm = 푘E ∙ 푓cm 1Τ3 • 퐸cm = 푘E − 푘E − 푘RA ∙ 훼RA ∙ 푓cm • Experimental database 1Τ3 • prEN1992: 퐸cm = 푘E ∙ 1 − 0.25 ∙ 훼RA ∙ 푓cm [9]

7100 1Τ3 • MC2020: 퐸cm = 푘E ∙ 1 − 1 − ∙ 훼푅퐴 ∙ 푓cm 푘E RAC provisions in prEN1992 and MC2020

Tensile strength

2Τ3 2Τ3 prEN 1992: 푓ctm = 0.3 ∙ 푓ck = 0.3 ∙ 푓cm − 8 ; for concrete strength class ≤ C50/60 1Τ3 and 푓ctm = 1.1 ∙ 푓ck ; for concrete strength class > C50/60

MC2020: 푓ctm = 1.8 ∙ ln 푓ck − 3.1 = 1.8 ∙ ln 푓cm − 8 − 3.1; for all strength classes

푏 푓 = 푎 ∙ 1 − 1 − ∙ 훼 ∙ 푓2Τ3 ctm 푎 푅퐴 ck

Experimental database For low RA content no change!

[9] RAC provisions in prEN1992 and MC2020

Stress–strain relationship Fracture energy

휎 푘∙휂−휂2 • prEN 1992: not treated • c = 푓cm 1+ 푘−2 ∙휂 0.15 • MC2020: 퐺퐹 = 85 ∙ 푓ck 1Τ3 • 휀c1 = 0.7 ∙ 푓cm ≤ 2.8‰ • Experimental database: 4 • 휀cu1 = 2.8 + 14 ∙ 1 − 푓cmΤ108 ≤ 3.5‰ 0.15 • 퐺퐹 = 1 − 0.4 ∙ 훼RA ∙ 85 ∙ 푓ck • Increases for RAC observed in experiments 1Τ3 • 휀c1 = 1 + 0.33 ∙ 훼RA ∙ 0.7 ∙ 푓cm ≤ 2.8‰ 4 • 휀cu1 = 1 + 0.33 ∙ 훼RA ∙ 2.8 + 14 ∙ 1 − 푓cmΤ108 ≤ 3.5‰

[9] RAC provisions in prEN1992 and MC2020

Shrinkage • Strong increase for RAC!

• RECYBETON: 휀cs,RAC 푡, 푡푠 = 1 + 0.82 ∙ 훼RA ∙ 휀cs 푡, 푡s [11]

0.30 100∙훼CRA • Tošić et al. 2018: 휀cs,RAC 푡, 푡s = 휉cs,RAC ∙ 휀cs 푡, 푡s = ∙ 휀cs 푡, 푡s ≥ 휀cs 푡, 푡s [12] 푓푐푚

• 휀cs,RAC 푡, 푡푠 = 1 + 0.8 ∙ 훼RA ∙ 휀cs 푡, 푡s

[12]

[9] RAC provisions in prEN1992 and MC2020

Creep • Strong increase for RAC!

[11] • RECYBETON: 휑RAC 푡, 푡0 = 1 + 0.9 ∙ 훼RA ∙ 휑 푡, 푡0

0.15 100∙훼CRA • Tošić et al. 2019a: 휑RAC 푡, 푡0 = 휉cc,RAC ∙ 휑 푡, 푡0 = 1.12 ∙ ∙ 휑 푡, 푡0 ≥ 휑 푡, 푡0 [13] 푓cm

• 휑RAC 푡, 푡0 = 1 + 0.6 ∙ 훼RA ∙ 휑 푡, 푡0 [13]

[9] RAC provisions in prEN1992 and MC2020

Durability • prEN 1992: If Exposure Resistance Classes (ERC) are not used, “traditional” cover recommendations are given • ERCs not envisioned by MC2020 • Qualitative literature review:

• Carbonation – cmin,dur,NAC + 5 mm

• Chloride ingress – cmin,dur,NAC + 10 mm RAC provisions in prEN1992 and MC2020

Flexural and shear strength

• Basing calculations on fcm – no need to modify flexural strength models

• For shear there is a need to increase γC! • Members not requiring shear reinforcement:

1Τ3 0.66 푑dg 11 푓ck 푑dg • 휏Rd,c ≥ 휏Rdc,min ⟹ ∙ 100 ∙ 휌l ∙ 푓ck ∙ ≥ ∙ 훾C 푑 훾C 푓yd 푑

• 푑dg = 16 mm + 퐷lower ≤ 40 mm for 푓ck ≤ 60 MPa

1Τ3 0.66 푑dg 11 푓ck 푑dg • 1 − 0.2 ∙ 훼RA ∙ ∙ 100 ∙ 휌l ∙ 푓ck ∙ ≥ 1 − 0.2 ∙ 훼RA ∙ ∙ 훾C 푑 훾C 푓yd 푑

• ddg limited to 16 mm RAC provisions in prEN1992 and MC2020

Deflection control • Decrease modulus; increase creep and shrinkage – not enough

• Decrease tension stiffening (Tošić et al. 2019b) [14]

2 휎sr • 푎 = 푎1 ∙ 1 − 휁 + 푎2 ∙ 휁; 휁 = 1 − 훽tRA ∙ 휎s

• 훽tRA = 1.0 for single, short − term loading

• 훽tRA = 0.25 for sustained or repeated loading • Expression for L/d can be used as long as modulus, creep and shrinkage are considered RAC provisions in prEN1992 and MC2020

Bond and anchorage/lap lengths • No differences observed relative to NAC

[9] 4. Implications for design and future work Implications for design and future work

Example: 6-m one-way slab in a residential building, As for ULS Shear strength: 4.0 C25/30 4.0

3.0 3.0

Ed Ed

/V 2.0

/V 2.0 [15]

Rd

Rd V

V C50/60 1.0 1.0 NAC RAC 0.2 NAC RAC 0.2 RAC 0.4 RAC 0.4 0.0 0.0 15 17 19 21 23 25 15 17 19 21 23 25 L/d L/d

Deflection control: 2.0 2.0 C50/60 C25/30 NAC 1.5 RAC 0.2 1.5

RAC 0.4 [15] lim

lim 1.0

1.0 a/a a/a NAC 0.5 0.5 RAC 0.2 RAC 0.4 0.0 0.0 15 17 19 21 23 25 15 17 19 21 23 25 L/d L/d Implications for design and future work

Directions for future work

Punching: critical for RAC use in residential and office buildings Existing research scarce or not fully representative

Carbonated RA: easier mix design, improvement of RAC fresh-state and hardened properties; structural behaviour?

Prestressed RAC: existing research scarce

Innovative reinforcements/: FRC, FRP, 3DPC, etc. REFERENCES

1. Tam, V.W.Y.; Soomro, M.; Evangelista, A.C.J. A review of recycled aggregate in concrete applications (2000-2017). Constr. Build. Mater. 2018, 172, 272– 292 2. Gálvez-Martos, J.-L.; Styles, D.; Schoenberger, H.; Zeschmar-Lahl, B. Construction and demolition waste best management practice in Europe. Resour. Conserv. Recycl. 2018, 136, 166–178 3. Silva, R. V.; De Brito, J.; Dhir, R.K. The influence of the use of recycled aggregates on the compressive strength of concrete: A review. Eur. J. Environ. Civ. Eng. 2015, 19, 825–849 4. Ignjatović, I.; Marinković, S.; Mišković, Z.; Savić, A. Flexural behavior of reinforced recycled aggregate concrete beams under short-term loading. Mater. Struct. 2013, 469, 1045–1059 5. Silva, R.V.; de Brito, J.; Dhir, R.K. Establishing a relationship between the modulus of elasticity and compressive strength of recycled aggregate concrete. J. Clean. Prod. 2016, 112, 2171–2186 6. Lye, C.Q.; Ghataora, G.S.; Dhir, R.K. Shrinkage of recycled aggregate concrete. In Proceedings of the Structures and Buildings, Proceedings of the Institution of Civil Engineers; ICE, 2016; pp. 1–25 7. Pacheco, J.; Brito, J. De; Soares, D. Destructive Horizontal Load Tests of Full-scale Recycled Aggregate Concrete Structures. ACI Struct. J. 2015, 112, 815– 826 8. Bodet, R.; Colina, H.; De Larrard, F.; Delaporte, B.; Ghorbel, E.; Mansoutre, S.; Roudier, J. Comment recycler le béton dans le béton: Recommendations du projet national Recybeton; 2018 9. Tošić, N.; Torrenti, J.M.; Sedran, T.; Ignjatović, I. Toward a codified design of recycled aggregate concrete structures : Background for the new fib Model Code 2020 and Eurocode 2. Struct. Concr. 2020, 1–23, doi:10.1002/suco.202000512 10. Pacheco, J.; de Brito, J.; Chastre, C.; Evangelista, L. Experimental investigation on the variability of the main mechanical produced with coarse recycled concrete aggregates. Constr. Build. Mater. 2019, 201, 110–120 11. De Larrard, F.; Colina, H. : Research and Practice; CRC Press: Boca Raton, 2019 12. Tošić, N.; de la Fuente, A.; Marinković, S. Shrinkage of recycled aggregate concrete: experimental database and application of fib Model Code 2010. Mater. Struct. Constr. 2018, 51, 126 13. Tošić, N.; de la Fuente, A.; Marinković, S. Creep of recycled aggregate concrete: Experimental database and creep prediction model according to the fib Model Code 2010. Constr. Build. Mater. 2019, 195, 590–599 14. Tošić, N.; Marinković, S.; de Brito, J. Deflection control for reinforced recycled aggregate concrete beams : Experimental database and extension of the fib Model Code 2010 model. Struct. Concr. 2019, 20, 1–15 15. Tošić, N.; Torrenti, J.M. New Eurocode 2 provisions for recycled aggregate concrete and their implications for the design of one-way slabs. Build. Mater. Struct. 2021, 64, 119–125 RAEng Frontiers Champion Project: Recycled Aggregate Concrete in South East Asia

THANK YOU FOR YOUR ATTENTION!

Nikola Tošić Universitat Politécnica de Catalunya [email protected]