This workshop is a deliverable of TRAC project which has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement Nº777823. Presentation 2: Utilization of Fine RCA together with MSWI Bottom Ashes TANG Luping, Chalmers University of Technology, Sweden Prof Tang received his PhD in 1996 at Chalmers University of Technology, Gothenburg, Sweden. Since then he has worked at SP Technical Research Institute of Sweden for 12 years and rejoined Chalmers since 2008 as professor and leader of research group for building materials. His main research interest is new types of cementitious materials and durability of concrete, especially chloride transport mechanisms and chloride induced corrosion of steel in concrete. In the past years he has been involved in several research projects dealing with greener cementitious materials including nano-technology and chemical activations.

1. Acknowledgement:
This project that has received funding from the European Union’s Horizon 2020 Research and Innovation
Programme under grant agreement no. 777823
TRAC 2nd International Workshop, online, 30th Dec 2020
Grant reference: 777823
Project acronym: TRAC
Size of funds: €450,000
Period: 1st July 2018 to 30th June 2022
Utilization of Fine RCA together with MSWI
Bottom Ashes
LupingTANG, Liming Huang & Emma ZHANG (Chalmers)

2. Outline
Background
Laboratory experiments
Preliminary results
Concluding remarks

3. The World Needs Sustainable Development
3

4. Concrete Recycling
4
0.063 0.125 0.25 0.5 1 2 4 8 16 32 64
Particle size, mm
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Chalmers Master’s thesis by Erik Johansson, 2011
Easier for reuse
Difficult for reuse

5. Ashes from Municipal Solid Waste Incineration (MSWI)
5
Source: Confederation of European Waste-Energy Plants, 2016
20% bottom ash per
incinerated waste!

6. Alkali-Activation Techniques
6
Using alkaline metal or alkaline
earth metal to activate the latent
hydration of minerals containing
silicon dioxide (SiO2) and
aluminum oxide (Al2O3) which
widely exist in the earth
as ”green” cementitious materials

7. Effect of Combined Additions for Shrinkage Control
7
Shrinkage (‰) = a1·Na2O% + a2 · SiO2% + a3 ·Gypsum% + b
-50
-40
-30
-20
-10
0
10
20
0 100 200 300 400
Drying duration, days
a1
a2
a3
SiO2
Na2O
Gypsum Expansion
Shrinkage

8. A Recently Published Paper
8

9. Laboratory Experiments
 Swedish RCA from an old road bridge
• Coarse RCA (>4 mm) has been tested in another project
with reasonably good results
• Our focus is on the fine part of RCA (0-4 mm)
 Average density about 2100 kg/m3
 Water absorption about 9% by dry mass of RCA

10. Mortar Content in RCA

11. Adsorption of Moisture by RCA Sand
• In general, fine particles adsorb more moisture
• Adsorption needs a long time to reach equilibrium
0%
1%
2%
3%
4%
5%
6%
7%
8%
9%
10%
< 0.075 0.075-0.125 0.125-0.25 0.25-0.5 0.5-1.0 1.0-2.0 2.0-4.0
Moisturecontentbymassofdrysample
Particle size, mm
6 days
16 days
32 days
63 days
262 days

12. 0 10 20 30 40 50 60
OPC-NS (Ref)
OPC-RFA0-4+2.5%w
OPC-RFA0-4+2.5%A
OPC-RFA0-4+3%A
CompressiveStrength [MPa]
(std curing)
7 days
28 days
Previous Results from Mortar Prisms
Almost just the effect of w/c ratio!
Eq. w/c 0.5
Eq. w/c 0.56
Eq. w/c 0.55
Eq. w/c 0.56

13. Previous Results from Mortar Prisms
AAS80: Alkali-activatd slag with 80%GGBS+20%OPC
0 10 20 30 40 50 60
AAS80-NS (Ref-A)
AAS80-RFA0-4+2.5%A
AAS80-RFA0-4+3%A
Compressive Strength [MPa]
24h(55°C,100%RH) 1d(55°C,100%RH)+20d(20°C,100%RH)

14. Bottom Ashes from Two Swedish MSWI Plants
14
Size Renova Fint 0-10 Stena Fint 0-10
0-0.5 mm 31.0% 23.3%
0.5-2 mm 39.3% 42.0%
2-10 mm 29.6% 34.7%
Moisture content
Renova Fint 0-10 15.32%
Stena Fint 0-10 14.40%
R-0-10 mm
S-0-10 mm
R-0-10 mm S-0-10 mm
R-0-10 mm
S-0-10 mm

15. Mineral Compositions of Bottom Ashes
15
0
5
10
15
20
25
30
35
40
45
CaO SiO2 Al2O3 Fe2O3 MgO TiO2 Mn2O3 Na2O MnO Na2O P2O5 K2O
[%]
Stena
S-0-05 S-05-2 S-2-10
0
5
10
15
20
25
30
35
40
45
CaO SiO2 Al2O3 Fe2O3 MgO TiO2 Mn2O3 Na2O MnO Na2O P2O5 K2O
[%]
Renova
R-0-05 R-05-2 R-2-10
R-0-10 mmS-0-10 mm

16. Harmful elements in Bottom Ashes
16
0
2000
4000
6000
8000
10000
12000
14000
As Ba Be Cd Co Cr Cu Hg Mo Nb Ni Pb S Sc Sn Sr V W Y Zn Zr
[mg/kg]
Stena
S-0-05 S-05-2 S-2-10
0
2000
4000
6000
8000
10000
12000
14000
As Ba Be Cd Co Cr Cu Hg Mo Nb Ni Pb S Sc Sn Sr V W Y Zn Zr
[mg/kg]
Renova
R-0-05 R-05-2 R-2-10
R-0-10 mmS-0-10 mm

17. Hydraulic Activities (The Solution Test)
17
Mix 2 g sample with 40 g NaOH (1 M),
rotated (12 rpm) at 40 °C for 7 days
Stop hydration acc to RILEM
recommendation
Heat at 105 °C and 350 °C,
respectively
Determine the mass change between

18. Results from The Solution Test
18
0%
1%
2%
3%
4%
5%
R005 R052 R210 S005 S052 S210
Hydrates
(massdifferencebtween105-350°C)
Samples
Raw
1M NaOH
Low hydraulic activity in all sorts of ashes!
Finer ashes revealed a relatively higher hydrates, possibly due to the wet storage

19. Manufacturing Green Sands
19
Ratio of RCA(0-2mm) to bottom ash: 1:0.5
Alkali-activator (water glass based): 30-40% by mass of bottom ash
before gas release after gas releaseMixing in a drum under rotation

20. CO2 Curing of Green Sands
20
CO2 filling
CO2 curing

21. 21
Particle Size Distribution of Green Sands
RCA:S:AS = 1:0.5:0.2
RCA:SL:AS = 1:0.35:0.15
S: S-bottom ash
SL: GGBS
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Passedportion(%)
Sieve size, mm
RCA0-2
S-RCA
SL-RCA
Funk&Dinger model

22. Application of Balls as Aggregate
22
Fresh status: Excellent workability of all specimens
NS: Natural sand; RCA: Recycled concrete aggregate size 0-2 mm
S025/R025: Stena/Renova bottom ashes size 0-0.25 mm
Standard mortar
Byggcem:sand:water = 1:3:0.5
Mix 0: Natural sand as ref
Sand in Mixes 1-3 (by vol%):
30% Sand (0-1 mm)+70% green sand
Mix 0 Mix 1 Mix 2 Mix 3

23. Results from Compressive Strength Test
23
Ref S025RCA R025RCA R025NS
0
10
20
30
40
50
60
Mix 0 Mix 1 Mix 2 Mix 3
Compressivestrength,MPa
2 days
7 days
28 days

24. Results from Compressive Strength Test
24
Mix 0: Ref (100% natural sand)
Mixes 1-3: 30% natural sand + 70% green sand
Mixes 4-6: 30% RCA0-2 + 70% green sand
(Mix 4: S-RCA; Mix 5: S-RCA with w/c 0.46; Mix 6: SL-RCA
0
5
10
15
20
25
30
35
40
45
50
Mix 0 Mix 1 Mix 2 Mix 3 Mix 4 Mix 5 Mix 6
Compressivestrength,MPa
7 days

25. Concluding Remarks
 Mixing RCA 0-4 mm with 2.5-3% alkali-activator can effectively keep the strength of AAS
mortar at the same level as using natural sand, but not for the OPC binder.
 Pre-treating RCA 0-2 mm with ground MSWI bottom ash by means of alkali-activation
technique can
effectively overcome the problem of fine RCA in workability of concrete, and
replace natural sand by 70-100% without markedly imparing compressive strength.
Our preliminary experimental results show that