1. ASSESSMENT OF THE ASR EXPANSION OF CONCRETE MADE WITH RECYCLED CONCRETE AGGREGATES
Luc BOEHME, Miquel JOSEPH
KU Leuven – Faculty of Engineering Technology – Department of Civil Engineering, Ostend, Belgium,

2. Content
The problem at hand
Research program
conclusions

3. The problem at hand Observations:
Recycling of CDW is essential in sustainable material cycles
Increasing amount of recycled aggregates
[*] COPRO - Activiteitenrapport 2014

4. The problem at hand Use of RCA in the context of a circular economy
 applications with added value are needed
 a.i. in structural concrete
BUT: lack of confidence in RCA due to
Lack of convenient standards and regulations
Insufficient prove of performance & behaviour of RC
Uncertainty about the origin of RCA
Hence questions about ASR in RC, amongst others

5. The problem at hand Origin of RCA used in the tests:
Is there a higher risk for ASR in concrete when using
coarse RCA ?
fine RCA ?
Origin of RCA used in the tests:
RCA 1 & RCA 2: crushed concrete waste from 2 different demolition sites
RCA 3: crushed disapproved freshly made concrete sewerage tubes

6. Research program Standard tests on fine and coarse RCA:
Aggregate size and particle size distribution
Amount of fines
Flakiness index
Density
Water absorption
Los Angeles abrasion value
Micro Deval wear resistance value
Coarse RCA  Expansion tests on concrete cores
Fine RCA  expansion tests on mortar prisms

7. Research program – results of standard test

8. Research program Coarse RCA: Expansion test on concrete cores
Principle = ASTM C 1293 & CSA A23,2-14A
Accelerated
Test samples: cores  100mm x 150 mm
curing in NaOH-solution at 38°C
to avoid dilution of alkali in pores
leading to under-estimation of expansion
@ 80°C = faster (24h) but less accurate
@38°C = longer, more reliable
Test period: 26 weeks
Measurements every 3 – 4 weeks
Test criterion: expansion < 0,040%
Method according to Touma [*]
[*]W.E. Touma, Alkali-Silica Reaction in Portland Cement Concrete: Testing Methods, and Mitigation Alternatives, PHD Thesis , University of Texas at Austin, 2000

9. Research Program Preparation of samples - concrete with coarse RCA
Concrete mixtures
Variation of RCA (influence of origin): RCA1 – RCA2 – RCA3
Variation of % replacement rate: 0 – 30 – 100%
Cement: 310 kg/m³
Variation of cement type:
CEM I/52,5 N – CEM III/A 42,5 N – CEM III/A 42,5 N LA
No plasticizer
Environmental Exposure Class: EE2  XC3 & XF1
Max W/C-ratio: 0,55
Aggregate grain size distribution: Bolomey-method

10. Research Program
Expansion tests on concrete cores – coarse RCA - results

11. Research Program Expansion tests on mortar prisms – fine RCA
Principle = ASTM C 1260
Samples: prisms 25 x 25 x 250 [mm]
Curing in 80°C
Test period: 16 days
Test criterion: expansion < 0,10%

12. Research Program Expansion tests on mortar prisms – fine RCA – results
Fine RCA from genuine
concrete demolition = ok
Fine RCA from demolished
early age concrete : n-ok

13. conclusions Coarse RCA (> 8mm)
has a strong potential to be used in recycling concrete
The properties of coarse RCA comply with the standard for aggregates for use in concrete (NBN EN 12620)
30% & 100% RCA: expansion test on genuine demolished concrete = ok
Expansion test on RCA from crushed early age concrete show potential risk
30% RCA: adequate protection against ASR when blast furnace cement or low-alkali cement is used

14. conclusions Fine RCA (0 – 8 mm) contains more old mortar paste
can contain other impurities that could influence the chemical reactivity such as ASR
fRCA from genuine demolished concrete = ok
fRCA from crushed early age concrete = unclear  additional tests !!

15. references
[1] R. V. Silva, J. De Brito and R. K. Dhir, Properties and compositions of recycled aggregates from construction and demolition waste suitable for concrete production, Construction and Building Materials, nr. 65, pp , 2014.
[2] L. Boehme, A. Van Gysel, V. Jeroen, M. Joseph and J. Claes, ValReCon20 – Valorisation of coarse recycled concrete aggregates in concrete C20/25 & C25/30, Oostende, Boehme, 2012.
[3] M. Behera, S. K. Bhattacharyya, A. K. Minocha, R. Deoliya and S. Maiti, Recycled aggregates from C&D waste & its use in concrete - A breakthrough towards sustainability in construction sector: A review, Construction and Building Materials, nr. 68, pp , 2014.
[4] P. Klieger and J. F. Lamond, Significance of Tests and Properties of Concrete and Concrete- Making Materials, ASTM, 1994.
[5] J. Apers and J.-F. Denoël, Concrete Technology - Chapter V, Belgian Concrete Association BBG, 2009.
[6] W. E. Touma, Alkali-Silica Reaction in Portland Cement Concrete: Testing Methods and Mitigation Alternatives, PhD Thesis: University of Texas at Austin, 2000.
[7] J. Lindgard, O. Andic-cakir, I. Fernandes, T. Ronning and M. Thomas, Alkali-silica reactions (ASR): Literature review on parameters influencing laboratory performance testing, Cement & Concrete Research, 2011.

16. Thank you for your attention !
Nieuwe tendensen in de wereld van de betontechnologie - Recyclage beton
Thank you for your attention !
Contact:
Luc Boehme
Program Director Construction Campus Ostend
Head of Research Group RecyCon
KU LEUVEN – Technology Campus Ostend
Zeedijk Oostende
Tel:
iiw.kuleuven.be/onderzoek/recycon