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Effect of fineness of cement on properties of fresh and hardened concrete S Ahmad*, University of Engineering & Technology, Pakistan 27th Conference on OUR WORLD IN CONCRETE & STRUCTURES: 29 - 30 August 2002, Singapore Article Online Id: 100027011 The online version of this article can be found at: http://cipremier.com/100027011 This article is brought to you with the support of Singapore Concrete Institute www.scinst.org.sg All Rights reserved for CIPremier PTE LTD You are not Allowed to redistribute or resale the article in any format without written approval of CIPremier PTE LTD Visit Our Website for more information www.cipremier.com

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Page 1: Effect of fineness of cement on properties of fresh and ... · PDF fileEffect of fineness of cement on properties of fresh and hardened concrete S Ahmad*, University of Engineering

 

Effect of fineness of cement on properties of fresh

and hardened concrete

S Ahmad*, University of Engineering & Technology, Pakistan

27th Conference on OUR WORLD IN CONCRETE & STRUCTURES: 29 - 30 August 2002,

Singapore

Article Online Id: 100027011 

The online version of this article can be found at:

http://cipremier.com/100027011

This article is brought to you with the support of 

Singapore Concrete Institute 

www.scinst.org.sg 

 

All Rights reserved for CI‐Premier PTE LTD 

You are not Allowed to re‐distribute or re‐sale the article in any format without written approval of 

CI‐Premier PTE LTD 

Visit Our Website for more information 

www.cipremier.com  

Page 2: Effect of fineness of cement on properties of fresh and ... · PDF fileEffect of fineness of cement on properties of fresh and hardened concrete S Ahmad*, University of Engineering

2]11' Conference on OUR WORLD IN CONCRETE & STRUCTURES: 29 - 30 August 2002, Singapore

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 m2/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).

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I ntrod 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 Clay Local quarries adjacent to factory Slate stone Mang, 14 km from factory Iron ores Mines near Attock (Punjab) Pakistan Gypsum Kohat (NWFP) Pakistan

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; Sample Fineness (cm2/kg) F1 1690 F2 2084 F3 2556 F4 2912 F5 3315 F6 3773

(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

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(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; Mix ratio WJC ratio No. of cubes 1 :2:4 0.65 09 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 cm2Jg. 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. (3) If workability is our prime factor, then a fineness of 2500 cm2Jg 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 2Jg without any undue increase in the grinding cost. However, further strength required will involve a substantial increase in the cost.

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Table-I: Results Of Cement Testing

Sample Fineness (Cmz/G)

Consistency (%)

Initial Setting Time (Min)

Final Setting Time (Min)

Expansion (mm)

3-Days Compo

Strength (Psi)

7-Days Compo

Strength (Psi)

28-Days Compo

Strength (psi)

Fl 1690 24.25 250 275 5 2967 4160 5382 F2 2084 24.50 235 260 15 3942 5062 6429 F3 2556 25 .50 230 260 5 4742 5862 6633 F4 2912 25 .50 220 245 7 5164 6225 7200 F5 3315 26.00 180 200 5 5438 6487 7825 F6 3773 26.50 150 180 2 5338 6299 7913

Table-2: Chemical Composition Of Cement Samples

Sample Fineness (cm2/g)

Chemical Composition (%) SiOz AI2 0 3 Fez 0 3 CaO MgO NazO S03 KzO Ti02 Mnz03

F1 1690 20.34 5.28 3.01 62.10 2.64 0.28 2.46 0.98 0.34 0.04 F2 2083 20.29 5.25 2.97 62.03 2.63 0.28 2.49 0.99 0.33 0.04 F3 2556 20.32 5.28 2.99 62.17 2.62 0.29 2.46 0.99 0.33 0.04 F4 2912 20 .28 5.28 2.99 62.09 2.64 0.28 2.54 0.99 0.33 0.04 F5 3315 20.29 5.26 3.00 62 .04 2.62 0.27 2.51 0.98 0.33 0.04 F6 3773 20.27 5.26 3.01 61.89 2 .59 0.28 2.58 0.99 0.33 0.04

Table-3: Results Of Concrete Testing

Fineness (Cm2/G)

Mix Ratio W/C Ratio Slump (mm)

Compacting Factor

3-Days Compo

Strength (Psi)

7-Days Compo

Strength (Psi)

28-Days Compo

Strength (psi)

1690

1:2:4 0.65 I 0.741 645 1114 2123 1:2:4 0.70 7 0.82 593 1218 1874

1:1.5:3 0.60 60 0.904 1280 2182 4092 1:1.5:3 0.65 - 0.94 760 1477 3279

2084

1 :2:4 0.65 7 0.803 1103 1732 2639 1:2:4 0.70 9 0.903 808 1551 2633

1:1.5:3 0.60 70 0.936 1280 2404 4203 1: 1.5:3 0.65 - 0.975 1083 2040 3436

2526

1:2:4 0.65 20 0.852 1650 2612 3081 1:2:4 0.70 50 0.95 1343 2331 3206

1: 1.5 :3 0.60 100 0.955 1764 2482 4529 1: 1.5:3 0.65 - 0.991 1202 2134 · 3676

2912

1 :2:4 0.65 20 0.855 1702 2800 3582 1:2:4 0.70 50 0.95 1424 2612 3591

1:1.5 :3 0.60 95 0.948 1780 2607 4727 1: 1.5:3 0.65 - 0.991 1520 2227 3876

3315

1:2:4 0.65 20 0.906 1936 3383 4340 1:2:4 0.70 70 0.972 1468 2810 3801

1: 1.5:3 0.60 100 0.958 2279 3467 4590 1: 1.5:3 0.65 - 0.994 1874 2186 3997

3773

1 :2:4 0.65 40 0.922 1905 3497 5246 1:2:4 0.70 72 0.965 1936 3102 4450

1: 1.5:3 0.60 130 0.964 2592 3825 5152 1: 1.5:3 0.65 - 0.982 1921 3060 4528

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Page 6: Effect of fineness of cement on properties of fresh and ... · PDF fileEffect of fineness of cement on properties of fresh and hardened concrete S Ahmad*, University of Engineering

• •

• •

Graph # 1: FINENESS VERSUS I.S.T.

260 •iii 240 w .... ::J z 220 • ~ w 200 '" ;:

180 •z '" ;: .... 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 .... 250::J Z •~ w 230:E ;: (!) Z 210;: .... W Vl •...J 190 Z '" ;;: •

170

150 1000 1500 2000 2500 3000 3500 4000

FINENESS (Cm'/g)

Graph # 3: FINENESS OF CEMENT VERSUS COMPRESSIVE STRENGTH OF MORTAR

CUBES

9000

8000

u;e:. 7000

:r .... 6000 Z '" w

5000 ~ CIl W 4000 U; CIl '"

3000w 0: 0­

'" 2000 0 U

1000

1500 2000 2500 3000 3500 4000

FINENESS (cm'/g)

107

1000

Page 7: Effect of fineness of cement on properties of fresh and ... · PDF fileEffect of fineness of cement on properties of fresh and hardened concrete S Ahmad*, University of Engineering

• • •

• •

Graph # 4: FINENESS OF CEMENT VERSUS SLUMP (MIX 1:2:4 WIC 0.S5)

45

40

35

30 E .s 25 a.

20=> '" ..J (J)

15

10

• •

1000 1500 2000 2500 3000 3500

FINENESS (Cm'lg)

Graph # 5: FINENESS OF CEMENT VERSUS COMPACTING FACTOR (MIX 1 :2:4 WIC 0.S5)

0.95

0.9 •• 0.85a::

0... 0.8 u <{ •...

0.75 to 2 • >= 0.7 U « 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 :l:... 3500

" z w 3000a:... <II 2500 w,.

2000in <II w \500a: Q.

'" '0000 0

500

1000 1500 2000 2500 3000 3500

FINENESS (cm'2/gj

108

4000

4000

Page 8: Effect of fineness of cement on properties of fresh and ... · PDF fileEffect of fineness of cement on properties of fresh and hardened concrete S Ahmad*, University of Engineering

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). [4] H.C. ENTROY, Trans. 8tn 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)

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