ALUMINATE CEMENTS COMPARED IN A TERNARY SYSTEM
Transcript of ALUMINATE CEMENTS COMPARED IN A TERNARY SYSTEM
FAST SET , HIGH EARLY STRENGTH SHRINKAGE COMPENSATED CEMENT BASED ON A TERNARY SYSTEM ALUMINATE CEMENTS,
CALCIUM SULPHATE AND PORTLAND CEMENT
Content
1. ternary binder
2. Binder
3. aim
4. tes5ng of different calcium aluminate
5. results
6. discussion
7. conclusion
Ternary binder
Aim forma5on of early e"ringite
a fibrous mineral crystal holding
32 water molecules
3CaO�Al2O3�3CaSO4�32H2O
C4A3Š
advantage
• fast set
• quick hardening
• high ini5al strength
• compensa5on shrinkage
• rapid drying
• cold weather
binder / phases
• CAC High alumina cement CA+C4AF +C12A7+C2AS • CSA Calcium sulpho aluminate C4A3Š +C2AS or C2S • ACA Amorpous calcium aluminate C12A7 +C2AS
• OPC ordinary Portlandcement C3S(alite)+C2S(belite) +C3A+C4AF4
• Anhydrite calcium sulphate CaSO4
Calcium aluminate
Calcium sulphate
Calcium silicate
portlandcement alumina cement
quarz
slag
SiO2
Al2O3 CaO
Portland cement
alumina cement
mayenite mono calcium aluminaat
test
• in accordance with EN-‐196 • 450 gram binder mixed with 1350 gram norm sand
• W/C : 0,5
• 0,3 % of organic retarder (added when se]ng was too quick)
• prisms 16x4x4 cm were filled and de-‐moulded at 2 hours
• 8 parts Portland cement (I.S EN 197-‐1:2011CEM I 52.5R)
• 1 part anhydrite • 1 part of a calcium aluminate
results mortars were tested on ;
• se]ng 5me
• hydra5on temperature
• compressive / flexural strength,
• dimensional stability
Vicat se]ng 5me min.
00:00
02:24
04:48
07:12
09:36
12:00
14:24
16:48
19:12
CSA ACA CAC
Begin se]ng
End se]ng
Temperature on hydra5on C°
0
10
20
30
40
50
60
00:00:00
00:01:20
00:02:40
00:04:00
00:05:20
00:06:40
00:08:00
00:09:20
00:10:40
00:12:00
00:13:20
00:14:40
00:16:00
00:17:20
00:18:40
00:20:00
00:21:20
00:22:40
00:24:00
00:25:20
00:26:40
00:28:00
00:29:20
00:30:40
00:32:00
00:33:20
00:34:40
00:36:00
00:37:20
00:38:40
00:40:00
00:41:20
00:42:40
00:44:00
00:45:20
00:46:40
00:48:00
00:49:20
00:50:40
00:52:00
00:53:20
CSA
ACA
CAC
Compressive strength MPa
0
10
20
30
40
50
60
70
80
6 hours 24 hours 2 days 3 days 7 days
CSA
ACA
CAC
Flexural strength MPa
0
2
4
6
8
10
12
6 hours 24 hours 2 days 3 days 7 days
CSA
ACA
CAC
Shrinkage/Expansion mm/m
0,00
0,01
0,02
0,03
0,04
0,05
0,06
0,07
0,08
0,09
0,10
6 hours 24 hours 2 days 3 days 7 days
CSA
ACA
CAC
discussion • Portlandcement is the dominant part of the binder in a
ternary matrix.
• important to note C3A , free lime , type and amount of sulfate
• Calcium sulfate goes in solu5on quickly
• it counts for the ini5al strength development and expansion
• type and amount (anhydrite, β / α hemi-‐hydrate, gypsum)
influence greatly the reac5vity , expansion and strength
development
discussion
• Calcium aluminate higher ra5o C/A increase reac5vity
• Mayenite (C12A7) is the most rapid phase compared to
other calcium aluminate minerals
• main hydrate formed C2AH8
• hexogonal , hydrates rapidly and is exothermic
• forms with Ca(OH)2 and CaSO4 highest amount of ehringite
conclusion • an op5mum in C/A ra5o and sufficient CaSO4 will react with Ca(OH)2
(formed at hydra5on of Portland cement) to form acicular
3CaO·∙Al2O3·∙3CaSO4·∙32H2O (eTringite/ C4A3S) crystals
• high ini5al strength and posi5ve expansion
• allows working at low temperatures
• ACA gave the most effec5ve results
• even at half the dosage
• lihle impact on se]ng 5me was no5ced
• ajer 48 hours strength was compara5vely in pace with other source
of aluminates