Investigation of MSWI mechanical properties based on the amount of - - PowerPoint PPT Presentation

Investigation of MSWI mechanical properties based on the amount

• f reactive

compounds

PhD Student:

• V. Ca pra i

Pro f.Dr. H.J.H. Bro uwe rs M.V.A F lo re a K . Sc ho llb a c h

Ove rvie w 1/ 12

• I

ntro duc tio n a nd mo tiva tio ns

• Cha ra c te riza tio n o f b y-pro duc ts (Physic a lly a nd c he mic a lly)
• Po zzo la nic a c tivity inve stig a tio n (T

GA, pa ste )

• Re a c tivity due to disso lutio n o f c he mic a l spe c ie s (I

so the rma l c a lo rime try)

• Suita b ility fo r c e me nt re pla c e me nt (E

N 450)

• Co nc lusio n

General overview

Mo tiva tio n 2/ 12

• Physic a l pro pe rtie s o f b y-pro duc t

(po ro sity, surfa c e a re a e tc .)

• Pre se nc e o f c o nta mina nts

(he a vy me ta ls, me ta llic Al a nd c hlo ride s)

Use o f b y-pro duc ts T re a tme nts fo r

• ptimiza tio n

Alka li a c tiva te d b y-pro duc ts Re a c tivity a na lysis

• F
• rma tio n o f ne w c o mpo und (C-A-S-H o r N-A-S-H)
• I

mmo biliza tio n o f c o nta mina nts

3/ 12

Divide d in 3 main fractions: Sma ll (s)  ϕ < 0.125 mm Me dium (m)  1 mm > ϕ > 0.125 mm L a rg e (l) 1 mm > ϕ > 4 mm

Chemical composition Particle size distribution

BA BA

Bo tto m Ash

L BA L BA

Lo w o rg a nic

c o nte nt

Bo tto m Ash

10 20 30 40 50 60 70 80 90 100 0,1 1 10 100 1000 Cumulative fines [%] Particle size [Micron] Q5 Q6 BA‐S LBA‐S Sludge CEM I 52.5 R

0,8 3,435 13,274 17,15 1,32 7,421 1,035 39,907 1,966 9,347 1,156 1,253

S-s

1,324 2,387 10,274 14,516 1,584 8,553 1,547 42,329 2,422 9,334 1,24 2,543 0,929

BA-s LBA-s

1,345 2,376 10,707 16,721 1,442 7,184 1,467 37,954 2,389 12,894 0,915 1,488 2,064

Chemical characterization

S

Sludg e

Admixtures CaCO3 content Metal Al Alkaline phases content Pozzolanic phases % w.t. % w.t % w.t. % w.t. S-s 1.61 0.1 10.5 30.40 BA-s 2.88 0.13 14.0 24.80 LBA-s 2.27 0.14 12.1 27.40

Cha ra c te riza tio n o f the b y-pro duc ts

Cha ra c te riza tio n o f the b y-pro duc ts 4/ 12

Visualization of by-products (SEM)

BA BA

Bo tto m Ash

L BA L BA

Lo w o rg a nic

c o nte nt

Bo tto m Ash S-s BA-s Physical properties

S

Sludg e

Admixtures Bulk density Specific gravity Moisture content Langmuir surface area g / c m3 g / c m3 % w.t m2/ g S-s 0.48 3.9 56 38.6 BA-s 0.56 4.1 21 25.2 LBA-s 0.56 3.7 21 14.6

Po zzo la nic a c tivity– T GA a na lysis 5/ 12

Methodology

Fraction tested: S-s, BA-s, L BA-s, Ca lc ium hydro xide (CH) Samples preparation: 50% e a c h fra c tio n + 50% CH + H

2O (w/ b = 0.8)

Reference: 50% SiO 2 + 50% CH Curing: Mo ulde d fo r 6 da ys a nd the n c ure d a t 97% RH Equipment: T G a na lysis Testing time: 7, 14, 28 da ys

Results

1. I nc re a sing po zzo la nic a c tivity within 14 da ys. S-s ha s the g re a te r po zzo la nic a c tivity. 2. At 28 da ys inc re me nta l fo rma tio n o f CH is re g iste re d. 3. Hig h pre se nc e o f c a lc ium spe c ie s, mo re tha n po zzo la nic , le a ds to the sa tura tio n o f the so lutio n re spe c t o f CH.

• 4,E

+00

• 4,E

+00

• 3,E

+00

• 3,E

+00

• 2,E

+00

• 2,E

+00

• 1,E

+00

• 5,E
• 01

0,E +00 5,E

• 01

1,E +00 80 85 90 95 100 105 30 130 230 330 430 530 630

DTG [%/min] Mass [%] Temperature [C]

Ma ss/ % Ma ss/ % Ma ss/ % DT G/ BA-s DT G/ BA-s+CH_7d DT G/ BA-s+CH_14d

72 39 85 65 62 39 54 48 87 20 40 60 80 100 7 d 14 d 28 d

CH content [%]

S-s+CH Ba -s+CH L Ba -s+CH

Po zzo la nic a c tivity– Me c ha nic a l stre ng th 6/ 12

Methodology

Fraction tested: S-s, BA-s, L BA-s, Ca lc ium hydro xide (CH) Samples preparation: 50% e a c h BA type + 50% CH Solution used: Wa te r (w/ b =0.8) Equipment: Co mpre ssive stre ng th te st Curing Conditions: 20°C (± 5°C) a nd 97% RH

Results

1. T he increasing porosity, due to the pa rtic le s sha pe a nd initia l ma c ro -po ro sity, re duc e s the me c ha nic a l stre ng th.

2. Expansion cracks a re visib le a lo ng the mo rta rs, due to CH c rysta lliza tio n.

3. Pre se nc e o f metallic Al inc re a se s the ma c ro po ro sity a nd g e ne ra te s a dditio na l c ra c ks.

0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 5 10 15 20 25 30

Compressive strength [MPa] Time [d]

S-s+CH stre ng th BA-s+CH stre ng th L BA-s+CH stre ng th

7/ 12

Methodology Results

Fraction tested: S-s, BA-s, L BA-s, CE M I 42.5 N (PC), Q5 (q ua rtz), Q6 Samples preparation: 75% PC+ 25% re pla c e me nt + H

2O (w/ b = 0.5)

Equipment: I so the rma l c a lo rime try Testing time: 5.5 da ys

Pre se nc e o f b o tto m a sh de la ys a nd pro lo ng s the re a c tio n o f C 3S a nd Afm Pre se nc e o f BA-s, L BA-s a nd S-s re sults in a n inc re a sing re a c tio n de g re e o f PC F ine r PSD fa vo urs the re a c tio n o f PC

Re a c tivity in c o nc re te – K ine tic a na lysis

22,49 14,49 26,32 2,93 12,85 2,93 5 10 15 20 25 30 35 BA-s S-s L BA-s

Reaction contribution [%] Bottom ash type

Che mic a l c o ntrib utio n PSD c o ntrib utio n

8/ 12

Methodology Results

Fraction tested: S-s, BA-s, L BA-s, CE M I 42.5 N (PC), Q5 (q ua rtz), Q6 Samples preparation: 75% PC+ 25% re pla c e me nt + H

2O (w/ b = 0.5)

Equipment: I so the rma l c a lo rime try Testing time: 5.5 da ys

L BA-s pro vide s the hig he st c o ntrib utio n in te rms o f re a c tivity a mo ng the po wde rs.

PS D c o ntributio n = Cum. he at OPCQn – Cum. he at OPC Re ac tivity c o ntributio n= Cum. he at OPCBAn – Cum. he at OPCQn

Q: q ua rtz n: PSD o f the po wde rs OPC: CE M I 42.5 N

Nomenclature Formulas

Re a c tivity in c o nc re te – K ine tic a na lysis

Re a c tivity in c o nc re te - Ca lc ula tio n o f SAI (stre ng th a c tivity inde x) 9/ 12

Methodology Results

Fraction tested: S-s, BA-s, L BA-s, CE M I 42.5 N (PC) Samples preparation: 75% PC+ 25% re pla c e me nt + H

2O (w/ b = 0.5)

Curing: 97 % RH Equipment: Stre ng th a c tivity inde x Testing time: 7, 14 da ys (28 da ys in pro g re ss) I f SAI ≥ 0.75 the re pla c e me nt ma te ria l can be used in b uilding ma te ria ls I f SAI < 0.75 the re pla c e me nt ma te ria l cannot be used in b uilding ma te ria ls

S-s ha s fine r PSD a nd L BA-s ha s a lo we r to ta l surfa c e a re a L BA ha s the hig he r stre ng th de ve lo pme nt with S-s Re a c tivity o f the pre c urso rs a ffe c ts the re a c tio n pro duc ts pe rfo rma nc e s

0,89 1,08 0,79 0,85 0,85 0,66 0,76 1,09 0,77 0,2 0,4 0,6 0,8 1 1,2 7 14 28

Activity index [-] Time [days]

S-sPC BA-sPC L BA-sPC

Co nc lusio ns 10/ 12

Conclusion

• Bo tto m a sh fro m He ro s Sluiskill B.V. (NL

) pre se nts simila ritie s with c la ss C fly a sh.

• T

he a c hie ve me nt o f sa tura tio n with re spe c t to CH inhibits the g e l fo rma tio n, a nd c o nse q ue ntly the stre ng th de ve lo pme nt due to e xpa nsio n.

• Stre ng th a c tivity inde x re a c he s 1.08 within 14 da ys, displa ying a n impro ve me nt in the re a c tio n de g re e due to

the c he mic a l c o mpo sitio n o f b o tto m a sh.

• Afte r 28 da ys, the inde x de c re a se s a g a in, due to the re duc tio n o f po zzo la nic a c tivity o f the pa ste s a nd

e xpa nsio n phe no me na .

Further research

• Me c ha nic a l tre a tme nts c a n b e a pplie d to inc re a se fine ne ss o f the po wde rs.
• Alka li a c tiva tio n b a se d o n silic a te a nd/ o r a lumina te c a n b e a tte mpte d.
• Alte rna tive silic a a nd a lumina so urc e b y-pro duc ts c a n pa rtia lly re pla c e the ma te ria l, suc h a s c la ss F

fly a sh o r hig h SiO 2-Al

2O 3 c o nte nt b o tto m a sh.

• De te rmina tio n o f T

OC c a n he lp the unde rsta nding o f the re a c tio n pro c e ss.

Que stio ns? 11/ 12

Ca CO 3 fo rma tio n a t 28 da ys 13

Admixtures CaCO3 content of pure ash CaCO3 content of by-products and CH at 28d % w.t. % w.t S-s 1.61 8.7 BA-s 2.88 19.75 LBA-s 2.27 8.8 72 39 85 65 62 39 54 48 87 20 40 60 80 100 7 d 14 d 28 d

CH content [%]

S-s+CH Ba -s+CH L Ba -s+CH 8,7 19,75 8,8 5 10 15 20 25 S-s BA-s L BA-s

CaCO3 content [% w.t]