Z E M C H 2 0 1 2 I n t e r n a t i o n a l C o n f e r e n c e
646
2. Experimental Plan
2.1 Experimental Plan
The plan for this experiment is shown on Table 1. The binder used the ordinary portland
cement, the regulated setting cement, and the atomizing EAF reducing slag powder. And
the gypsum calculated the optimal value for the ettringite generation following the ratio to
set for 30%, and based on the calculation, the EAFRS was replaced in 4 levels of 0, 20,
30, and 40%. In general, the Portland cement and the regulated setting cement were
used alone without adding the gypsum as the contrasting group for this experiment. For
the measurement category, in the paste phase, it implemented the setting test,
temporary thermal hydration test and hydration analysis, and, in the mortar phase,
compression strength for each material age, and length change were measured.
Table 1 : Experimental plan
Factors
Levels
Test items
Substitution
ratio of
gypsum(%)
OPC
1)
, RSC
2)
EAFRS
3)
(0, 20, 30, 40)
Paste
Setting time
Hydration Heat(Modified adiabatic
temperature)
Hydrates analysis
Mortar Compressive strength
Length variation
1) OPC : Ordinary Portland Cement as the control without gypsum.
2) RSC : Regulated Setting Cement as the control without gypsum.
3) EAFRS : EAF Reducing Slag with gypsum of pre-decided rate
2.2 Using Materials
The binders used in the experiment were the finite crushed materials by the ball mill after
cooling the fused EAF in high speed air spray method as well as regulated setting
cement and ordinary Portland cement. Property characteristics on each binder and
oxidation analysis are shown on Table 2. The chemical composition of the gypsum used
as the mixed material is shown on Table 3. The regulated setting cement and the CA
binder diluted the retardation agent for 0.5% for the binder volume on the combination
water for securing the workability by the drastic setting.
Table 2 Physical & chemical properties of binders
Binders
Physical properties
Oxide content(Wt.%)
Density(g/
㎤
)
Fineness(
㎠
/g)
SiO
2
CaO Al
2
O
3
Fe
2
O
3
MgO MnO
OPC
3.15
3,200
17~25 60~67 3~8 0.5~6 0.1~4
-
RSC
2.87
4,800
10~16 47~53 14~20 3.0
2.5
-
EAFRS
2.97
5,500
10.9
44.5
26.6
4.3
6.6
0.6
Table 3 Chemical composition of gypsum
Type
MgO Al
2
O
3
SiO
2
SO
3
CaO Fe
2
O
3
SrO
HG
(Hemihydrate Gypsum) 0.32
0.88
2.57 55.79 39.99 0.41
0.04
