Civil Engineering Reference
In-Depth Information
Table 3.2 Comparison table of clinker mineral component and property produced in 1980 and
2010
Mineral name
Chemical formula
Item
Year
Content/%
Tricalcium silicate
3CaO
·
SiO
2
C
3
S
1980
47
-
55
2010
55
63
-
Dicalcium silicate
2CaO
·
SiO
2
C
2
S
1980
17
31
-
2010
13
-
25
Tricalcium aluminate
3CaO
·
Al
2
O
3
C
3
A
1980
8
10
-
2010
1
15
-
Tetracalcium aluminferrite
4CaO
·
Al
2
O
3
·
Fe
2
O
3
C
4
AF
1980
10
-
18
2010
8
-
16
Fineness/(m
2
/kg)
1980
250
300
-
2010
350
420
-
Final setting time/minute
1980
210
-
270
2010
180
210
-
Admixture dosage/%
1980
6
10
-
2010
10
-
20
Note
All data in 1980 are cited from the topic
concrete manual
published by Jilin science and
technology press in 1986
cement manufacturer. However, overdosage of admixture will
lessen concrete
strength at early age, enlarge shrinkage, and shrinking rate.
5. Changing of mineral component
Looking over the technology progress in cement industry for hundreds of years,
approach for increasing cement strength is mainly boosting
fineness and changing
mineral component. Table
3.2
is a mineral component and property comparison of
cement produced in 2010 and cement produced before 1980 by taking 42.5-grade
ordinary Portland cement as an example.
As we can see from Table
3.2
,C
3
S content which is bene
cial to strength of
cement and concrete has been boosted a lot, while content of C
2
S which has a low
strength growth rate has been reduced. What is more,
fineness has been greatly
increased and
final setting time has been shortened in turn.
In short, due to the progress of machinery industry especially in recent 10 years,
the feature of cement industry has changed a lot.
Talking about the output, single annual output of the eight largest cement fac-
tories in China is less than 2 or 3 million tons. For modern large-scale cement
factory, annual output is approximately above 5 million tons. For example, the
largest cement brand
—
Hailuo cement
—
has an annual output of several hundreds
million tons.
Talking about the output for single kiln, kiln with an output of several thousand
tons per day could be regarded as big kiln 10 years ago, while kiln with an output of
10,000 per day had already under worked during production nowadays. Besides,
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