Effect of fineness of cement on properties of fresh
and hardened concrete
S Ahmad*, University of Engineering & Technology, Pakistan
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Singapore
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Effect of fineness of cement on properties of fresh
and hardened concrete
S Ahmad*, University of Engineering & Technology, Pakistan
Abstract
This paper presents the effect of fineness of cement on properties of fresh and
hardened concrete. The objective of this paper was to see these effects on the indigenous
cement of same chemical composition. For this reason, clinker of same chemical
composition was used. Six different fineness ranging from 169 to 333 m 2/kg were used.
British Standards were followed during these investigations. Mortar cubes were cast using
Ottawa sand and their compressive strength tested at 3,7 and 28 days. Other physical
properties of cement i.e. , consistency, initial & final setting time, and soundness were also
determined for all six finenesses. To see the effect of fineness of cement on properties of
concrete, two concrete mixes (1 :2:4 & 1 :1.5:3) with two wlc ratios (0.65 and 0.70 for 1 :2:4
and 0.60 and 0.65 for 1: 1.5:3) were made. For workability slump test and compacting factor
tests for each mix were performed. For compressive strength two hundred & sixteen cubes
of 6" x 6" x 6" were tested at the age of 3, 7 & 28 days. Graphs were drawn between the
fineness and different properties of cement & concrete. It was noted that consistency and
compressive strength of cement increased by increasing fineness while setting times of
cement decreased with fineness . No general pattern could be obtained between fineness
and expansion. Compressive strength of concrete increased with fineness. Workability in
terms of slump and compacting factor of fresh concrete increased by increasing fineness.
However this pattern is prominent upto 250 m2/kg. After this value it was insignificant.
Keywords: Cement, fineness, workability. concrete
Literature Review:
1. Most of the researchers in the past claimed that strength of cement increases with fineness . In these
researchers. AM. NEVILLE [5], W.H. PRICE [1], U.S. BUREAU OF RECLAMATION [2], F.M . LIE [6],
KUHL (3). H.C. ENTROY [4) . M. VENAUL T [7]. F.W. LOUCHER [8], J. WOHRER [9], K. SEHWEDEN
[8], M.J.M. JASPERS [10) AND E.C. HIGGINSON [11) are included .
2. The water content of paste of standard consistency is greater, the finer the cement but conversely an
increase in fineness of cement improves the workability of a concrete mix. This idea was presented by
AM . NEVILLE [5), W .H. PRICE [1), U.S. BUREAU OF RECLAMATION [2], J. WOHRER, A RIO & F.
VON BALDASS [9) and E.C. HIGGINSON [11).
103
Introd uction:
Concrete is one of the most commonly used construction material all over the world . It is a mixture of
different ingredients as cement, coarse aggregate, fine aggregate and water. The individual properties of
each ingredient has tremendous influence on the properties of concrete. Among the constituent materials,
cement is the most important and costly material. Its properties greatly affect the properties of resulting
concrete.
"Fineness", defined as "the total surface area of the cement that is available for hydration", has great
influence on properties of fresh and hardened concrete.
In this research, cement samples of different fineness were prepared in the laboratory keeping other
properties same, like chemical composition, amount of gypsum etc. For each sample, tests regarding other
properties of cement like consistency, initial setting time, final setting time, expansion, compressive strength
were performed . Concrete cubes were cast in the laboratory as per British Standards. Two mix ratios and for
each mix ratio, two w/c ratios were used. In fresh state, slump test and compacting factor tests were carried
out to see the influence of changing fineness on workability. Compressive strength at the age of 3, 7 and 28
days was obtained and graphs were drawn to show the effect of fineness of cement on these properties.
Blaine's air permeability apparatus was used to measure fineness (cm2/g) of different cement samples.
XRF-cement spectrometer was used to verify the chemical compositon of cement samples. Cement clinker
was taken from Bestway Cement Factory, situated at 10 km aerial distance from University of Engg. & Tech.,
Taxila (place of research). The factory uses the following sources of raw materials for the production of
clinker:
Material
Source
Lime stone
Local quarries adjacent to factory
Local quarries adjacent to factory
Clay
Mang, 14 km from factory
Slate stone
Iron ores
Mines near Attock (Punjab) Pakistan
Kohat (NWFP) Pakistan
Gypsum
Preparation of Test Samples:
(1) More than 350 kg of cement clinker having the same chemical composition was collected from the
factory, while the kiln was working smoothly. The clinker was brought to laboratory and stored
temporarily in polythene bags.
(2) Sieve analysis of this clinker as well as of gypsum to be mixed was carried out in the factory.
(3) The clinker was crushed into smaller sizes by passing successively through two jaw crushers of different
sizes .
(4) Gypsum was also crushed into semi-powered form by passing through the smaller sized jaw crusher.
(5) The crushed clinker from (3) was mixed with 4% gypsum from (4) and finely ground in iron-jar type ball
mill at different fineness levels in the laboratory.
(6) After continuous grinding of more than one month, the following samples were prepared, weighing more
than 50 kg each;
2
Fineness (cm /kg)
Sample
F1
1690
F2
2084
F3
2556
F4
2912
3315
F5
3773
F6
(7) The prepared samples were sealed in polythene bags and marked accordingly .
Experimental Programme:
(1) Chemical composition of all the samples were analysed by XRF-cement spectrometer/cement analyser.
The chemical composition shown in table-1 confirms the uniform oxide composition of all samples.
(2) For cement testing, the following tests were performed on each sample by adopting British Standard:
(i) Consistency
(ii) Initial Setting Time
(iii) Final Setting Time
(iv) Expansion
(v) Compressive Strength of Mortar Cubes
104
(3) For concrete testing, 6 inch . cubes were cast from the prepared test samples by adopting British
Standard. The following casting schedule was prepared for each test sample;
WJC ratio
No. of cubes
Mix ratio
09
1:2:4 0.65
1:2:4 0.70
09
1:1.5:3 0.60
09
1:1.5:3
0.65
09 As there were six test samples, a total no. of (6 x 36) 216 cubes were prepared. (4) Just after mixing of each batch of concrete, the following workability tests were performed on fresh
concrete.
i)
Slump test
ii) Compacting factor test
(5) 6 inch cubes were cast from the test samples in accordance with BS 1881: Part 108,111 , 116: 1983.
The cubes were stored for 24 hours at a temperature of 20°C and relative humidity 90%. At the end of
this period, the cubes were cured in a temperature controlled water bath. Their 3, 7 and 28 days
compressive strength was checked in a 3000 kN compression machine. Results from testing of fresh
and hardened concrete samples are shown in table-2.
Results and Discussion:
1. Cement Testing:
Results of cement testing are shown in table-1. It is evident from these results that consistency and
compressive strength of mortar cubes increases with fineness while initial setting time and final setting time
decreases with increasing fineness . These effects have been shown graphically in graph 1, 2 & 3.
2. Concrete Testing:
The results of workability tests and compressive strength tests are summarized in table-3.
(a) Workability:
(i) For all mix ratios and wJc ratios, slump and compacting factor, hence workability of fresh concrete
increases with increasing fineness. Typical curves showing effect of fineness on slump and
compacting factor are shown in graph 4 & 5.
(ii) Curves in graph 4 & 5 show a local peak in slump and compacting factor at a fineness of about
2500 cm 2Jg, after which these remain constant upto 3000-3500 cm 2Jg. Then there occurs a gradual
rise at higher values of fineness .
(b) Compressive Strength:
Compressive strength of concrete cubes, cast from test samples was checked as the main property of
hardened concrete. Typical curves showing the effect of fineness on compressive strength are shown in
graph 6. According to these, compressive strength increases with increasing fineness.
Conclusions:
(1) According to previous research , the effect of fineness on workability is controversial. However, our
results on local cement show an increase in workability with the increase in fineness.
(2) According to this research, compressive strength of hardened concrete increases with increasing
fineness. This trend is in accordance with the previous research published.
2
(3) If workability is our prime factor, then a fineness of 2500 cm Jg will be sufficient and the cost involved in
further grinding may be saved . But if emphasis is on the strength of concrete, then the cement may be
ground upto 3000 cm 2 Jg without any undue increase in the grinding cost. However, further strength
required will involve a substantial increase in the cost.
105
Table-I:
Sample
Fl
F2
F3
F4
F5
F6
Fineness
(Cmz/G)
Consistency
1690
2084
2556
2912
3315
3773
24.25
24.50
25 .50
25 .50
26.00
26.50
(%)
Initial
Setting
Time
(Min)
250
235
230
220
180
150
F1
F2
F3
F4
F5
F6
Fineness
(cm2/g)
1690
2083
2556
2912
3315
3773
SiOz
20.34
20.29
20.32
20 .28
20.29
20.27
Final
Setting
Time
(Min)
275
260
260
245
200
180
AI 2 0 3
5.28
5.25
5.28
5.28
5.26
5.26
Fez 0 3
3.01
2.97
2.99
2.99
3.00
3.01
Table-3:
Fineness
(Cm 2 /G)
1690
2084
2526
2912
3315
3773
Expansion
(mm)
5
15
5
7
5
2
3-Days
Compo
Strength
(Psi)
2967
3942
4742
5164
5438
5338
7-Days
Compo
Strength
(Psi)
4160
5062
5862
6225
6487
6299
28-Days
Compo
Strength
(psi)
5382
6429
6633
7200
7825
7913
Chemical Composition Of Cement Samples
Table-2:
Sample
Results Of Cement Testing
Mix Ratio
W/C Ratio
1:2:4
1:2:4
1:1.5:3
1:1.5:3
1:2:4
1:2:4
1: 1.5:3
1: 1.5:3
1:2:4
1:2:4
1: 1.5 :3
1: 1.5:3
1:2:4
1:2:4
1:1.5 :3
1: 1.5:3
1:2:4
1:2:4
1: 1.5:3
1: 1.5:3
1:2:4
1:2:4
1: 1.5:3
1: 1.5:3
0.65
0.70
0.60
0.65
0.65
0.70
0.60
0.65
0.65
0.70
0.60
0.65
0.65
0.70
0.60
0.65
0.65
0.70
0.60
0.65
0.65
0.70
0.60
0.65
Chemical Composition (%)
CaO
MgO NazO S03
62.10
2.64
0.28
2.46
62.03
2.63
0.28
2.49
2.62
62.17
0.29
2.46
2.64
62.09
0.28
2.54
62 .04
2.62
2.51
0.27
2 .59
61.89
0.28
2.58
KzO
0.98
0.99
0.99
0.99
0.98
0.99
Ti0 2
0.34
0.33
0.33
0.33
0.33
0.33
Mnz03
0.04
0.04
0.04
0.04
0.04
0.04
Results Of Concrete Testing
Slump
(mm)
Compacting
Factor
I
0.741
0.82
0.904
0.94
0.803
0.903
0.936
0.975
0.852
0.95
0.955
0.991
0.855
0.95
0.948
0.991
0.906
0.972
0.958
0.994
0.922
0.965
0.964
0.982
7
60
7
9
70
20
50
100
-
20
50
95
20
70
100
40
72
130
-
106
3-Days
Compo
Strength
(Psi)
645
593
1280
760
1103
808
1280
1083
1650
1343
1764
1202
1702
1424
1780
1520
1936
1468
2279
1874
1905
1936
2592
1921
7-Days
Compo
Strength
(Psi)
1114
1218
2182
1477
1732
1551
2404
2040
2612
2331
2482
2134
2800
2612
2607
2227
3383
2810
3467
2186
3497
3102
3825
3060
28-Days
Compo
Strength
(psi)
2123
1874
4092
3279
2639
2633
4203
3436
3081
3206
4529
· 3676
3582
3591
4727
3876
4340
3801
4590
3997
5246
4450
5152
4528
Graph # 1: FINENESS VERSUS I.S.T.
260
iii
240
::J
220
w
;:
200
w
....
z
~
'"
'....z"
•
•
•
•
•
180
;:
160
w
•
Vl
...J
140
~
120
!!
....
100
1000
1500
2000
2500
3000
3500
4000
FINENESS (CM'/G)
Graph # 2: FINENESS OF CEMENT VERSUS F.S.T.
290
•
270
iii
UJ
....
::J
250
•
•
Z
~
w
;:
:E
•
230
(!)
Z
;: 210
•
....
W
Vl
...J
'"
190
•
Z
;;:
170
150
1000
1500
2000
2500
3500
3000
4000
FINENESS (Cm'/g)
Graph # 3: FINENESS OF CEMENT VERSUS COMPRESSIVE STRENGTH OF MORTAR CUBES 9000
8000
u;
e:.
7000
:r
....
6000
'"w
•
Z
~
CIl
W
'"
5000
4000
U;
CIl
w
3000
0:
0­
'"
0
2000
U
1000
1000
1500
2000
2500
FINENESS (cm'/g)
107
3000
3500
4000
Graph # 4: FINENESS OF CEMENT VERSUS SLUMP
(MIX 1 :2:4 WIC 0.S5)
45
•
40
35
E
.s
a.
'=>"
30
25
•
20
..J
(J)
15
10
1000
•
1500
•
•
•
2000
3000
2500
3500
4000
FINENESS (Cm'lg)
Graph # 5: FINENESS OF CEMENT VERSUS COMPACTING FACTOR
(MIX 1 :2:4 WIC 0.S5)
0.95
0.9
a::
...u0
...
0.85
•
0.8
<{
to
2
•
0.75
>=
U
0.7
Q.
0 .65
•
•
•
•
«
'"
0
U
O.S
0.55
0.5
1000
\500
2000
2500
3000
3500
4000
FINENESS (Cm'/g)
Graph # 6: FINENESS OF CEMENT VERSUS COMPRESSIVE STRENGTH OF CONCRETE CUBES (MIX 1:2:4 WIC 0.70)
5000
4500
in
!!o­
4000
...
3500
w
3000
:l:
"z
...
a:
<II
,.
w
in
2500
2000
<II
w
a:
Q.
'"
0
0
\500
'000
500
1000
1500
2000
2500
FINENESS (cm'2/ gj
108
3000
3500
4000
Reference:
[1) W.H . PRICE, Factors affecting concrete strength . J. AMER CONC . Inst. 47, pp. 417-32 (Feb. 1951).
[2] U.S. BUREAU OF RECLAMATION , Investigations into the effects of Cement Fineness and alkali
cement on various properties of conc. And mortar conc. Laboratory report on C-814 (Denver,
COLORADO, 1956).
[3] KUHL, Cement Chemistry in Theory and Practice, pss (LONDON 1931).
tn
[4] H.C. ENTROY, Trans . 8 Inst. Cong ., Large Dams, 3, 193 (1964).
[5] Properties of Con c., 4th Edition , by A.M . NEVILLE (1995) .
[6] Chemistry of Cement and Conc. By F.M. LIE.
[7] M. VENAUL T, Revue meter Const. Tran . Publ. , Nos.550-553 (1961) , 595-596 (1965) .
[8] F.W . LOUCHER , WOHRER and K.SEHWEDEN, Tonind - ztg, keram Rdsh . 90, 547 (1966).
[9] J. WOHRER Zement - kalk gips 3, 148 (1950) , A.RIO and F. VON BADASS.
[10] M.J.M. JASPERS, Revue meter Const. Tran . Publ., Nos.429,160,430,207,431 ,254 (1951) W . CZERNIN ,
Zement- KALK- GIPS, 7160 (1954).
[11] E.C . HIGGINSON , "The effect of cement fineness on conc." Fineness of cement, ASTM STP 473,
American Society for Testing and Material , 1970, pp 71-81 .
[12] British Standard (B.S . 12: 1991)
[13] British Standard (B .S. 4550)
[14) British Standard (B .S. 1881)
109