F. Falade is a Professor of Engineering at the Civil & Environmental Eng i- neering Department, Faculty of Engineering, University of Lagos, Nigeria. Tel.: +2348023073313, E-mail.: ffalade@hmail.comInternational Journal of Scientific & Engineering Research Volume 3, Issue 7, June-2012 1
ISSN 2229-5518
Potential of Pulverized Bone as a Pozzolanic material
F. Falade, E. Ikponmwosa, C. Fapohunda
Abstract— This paper presents the results of a study on the potential use of pulverized bone (PB) as a pozzolanic material and supplementary cementing material in the production of concrete. Tests were conducted to determine the influence of pulverized bone on the consistency and the setting times of cement paste at different percentages of replac ement from 0 to 100% at interval of 10%, using the Vicat Apparatus. 75mm cubes of cement/sand mortar were prepared from a mixture of cement and sand in the proportion of 1: 3 with water/cement ratio of 0.4 in order to determine its strength development pattern. The chemical composition of pulverized bone was also determined. The results showed that the incorporation of pulverized bone into cement paste resulted in low water demand to ac hieve the same consistency by as much as 30%. Also, the addition of pulverized bone into cement brought about delayed setting times of the paste indicating that the pulverised bone has a retarding effect on the paste. The results further indicate that pulverised bone c ould be used as a partial replacement of cement without damage to the strength provided that the level of replacement does not exceed 20%. Results of investigation showed that at up to 20% replacement of cement with pulverized bone, there was no significant difference in the 28-day strength of the specimens containing pulverised bone and the control specimens (without pulverised bone). From the results of this study, it can be concluded that pulverised bone has pozzolanic properties and it can be used as partial replacement of cement in concrete.
Index Terms— Cow bone, Consistency, Pozollans, Pulverized bone, Setting times.
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HE scarcity of building materials especially cement and its attendant high cost in Nigeria has made it difficult for
low-income earners that constitute the majority of the population, to own their own houses, and also put in jeopardy the construction of civil engineering infrastructure that is needed for national development. The scarcity of cement has made it incumbent on researchers to find a cheaper, dependa- ble and durable substitute material that can be used to partial- ly replace the cement content for concrete production. One of the directions that researchers have beamed their searchlight on is the use of pozzolanic materials. Pozzolans are siliceous or siliceous and aluminous materials which in themselves do not possess any cementitious value but in finely divided form and in the presence of moisture will chemically react with calcium hydroxide (CH) to form a compound with cementi- tious value according to this general equation:
Pozzolans + CH C-S-H …… [1]
Calcium silicate hydrates (C-S-H) is the strength-forming products of cement hydration. Pozzolans can be classified as artificial if firing (or calcination) is required to induce pozzo- lanicity and natural if no calcination is required.
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E. Ikponmwosa is a Senior Lecturer at the Civil & Environmental Engi-
C. Fapohunda is currently pursuing Doctor of Philosophy degree program
in Materials & Structures at the Civil & Environmental Engineering De-
partment of the University of Lagos, Nigeria.
In recent times, by-products of industrial and agricultural ac- tivities often in the form of wastes have become the major source of pozzolanic materials which have been used as par- tial replacement of cement in the production of strong and durable concrete. Hussin and Abdullah [2] worked on palm oil fuel ash (POFA), and concluded that it has a beneficial ef- fect on concrete provided the percentage replacement does not exceed 30%. Givi et al. [3] researched on rice husk ash (RHA). They showed that rice husk ash increased the setting times, improved workability, and increase the compressive and flex- ural strengths of concrete. Wilson and Ding [4] investigated the performance of fly ash in mortar and concrete. Their work indicated that the use of fly ash enhanced the workability and increased the setting times of cement mortar and concrete. Yilmaz [1] worked on silica fume and observed delayed set- ting times, increase in water demand and reduction in per- meability with the use of silica fume. Falade [5] researched on saw dust ash (SDA). He concluded that the addition of saw- dust ash decreased concrete strength and noted that the rate of gain of strength was more rapid in curing ages of 21 and 28 days, especially in the mixures with high percentage of SDA. Fapohunda [6] investigated the potential of granulated blast furnace slag to produce durable concrete. He concluded that the use of slag increased the ability of concrete to withstand chloride ingress, thus helping to produce durable concrete. Salau and Olonade [7] conducted a research into the pozzolan- ic potentials of cassava peel ash (CPA) on cement paste and mortar cube specimens. Their results showed that CPA re- tarded the rate of hydration reaction and setting times of ce- ment paste; and at up to 15% replacement of cement with CPA, there were no significant different in the 90 days flexural and compressive strength when compared with the control sample (specimen without CPA).
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This paper reports on experimental investigation of the pozzolanic potential of pulverised bone as there is little infor- mation on the subject. Thus the objectives of this work are to:
i) Determine the quantity of cow bone that is available using Lagos State, Nigeria as a case study
ii) Determine the composition of pulverized bone
iii) Investigate the influence of pulverized bone on the
consistency and the setting times of paste incorporat-
ing pulverized bone
iv) Assess the strength development of cement-sand
mortar incorporating pulverized bone.
For this experiment, Ordinary Portland conforming to BS 12 [8] was used. The cow bones were obtained from Oko-Oba abattoir in Agege Local government of Lagos State, Nigeria. The bones were dried after they have been separated from all the muscles, flesh, tissues, intestines and fats. The dried bones were then milled or pulverized through a bone mill into powder, and the fraction passing through 150µm was later packaged in bags and stored in cool dry place. The availability of cow bone to meet the demand for its use was also investi- gated taking Lagos metropolis as a case study. The following
75mm cubes of cement/sand mortar were prepared from a mixture of cement and sand in the proportions of 1: 3, and with water/cement ratio of 0.4. The specimens were prepared in accordance with BS 4551 [9]. Thereafter, the cement content of the mortar was progressively replaced with pulverised bone to the level of (80%) where the mixture could not set again because of high pulverized bone content. The replacement level was from 0 - 80% at the interval of 10%.
The results of partial replacement of cement with pulverized bone in cement/sand mortar are presented below:
The outcome of investigation into the availability of cow bones in the Lagos metropolis is presented in Tables 1 and 2
Table 1: Location of Source of Cows Bone in Lagos
State, Nigeria
tests were conducted on cement/pulverized bone paste, and
cement/pulverized bone-sand mortar:
Oko Oba,
In order to determine the constituents of pulverized bone, samples were subjected to analysis using the combination of Spectrophotometer, Atomic Absorption Spectrophotometer
1 Agege Abattoir 1500
Ashkpo, Aje-
2 gunle Abattoir 100
Slaughter
and Gravimetric methods at the Department of Chemistry, University of Lagos, Nigeria.
3 Itire
Slab 60
4 Matori Slaughter
Slab
Slaughter
Water requirement to achieve the standard consistency of ce- ment paste were carried out in accordance with BS 12 [8], us- ing the Vicat probe and the Vicat needle apparatus, by partial- ly replacing cement with pulverised bone at different cement replacement levels ranging between 10 and 100% at 10% inter- vals. Water demand for standard consistency was determined for each percentage replacement of cement with pulverized bone. The water demand for zero replacement of cement with pulverised bone serves as the control.
5 Aswani
6 Coker Aguda
7 Ilaje
8 Badagry
9 Ikorodu
Slab 15
Slaughter
Slab 15
Slaughter
Slab 20
Slaughter
Slab 25
Slaughter
Slab 80
In order to assess the effect of pulverized bone on the setting
10 Epe Slaughter
Slab
Slaughter
times (initial and final) of cement paste, the water required to achieve the standard consistency of cement paste at zero per- cent pulverized bone replacement, measured by the water content that produced a paste that allows the Vicat plunger to sink to between 5 and 7mm from the bottom of the Vicat
11 Ejigbo **
12 Oke Aro **
13 Goshen
(Agege) **
Slab -
Slaughter
Slab -
Slaughter
Slab -
mould, determined in accordance with BS 12 [8], was used for
this investigation. The water content was 30% (or w/c = 0.3).
The setting times (initial and final) at the standard consistence
of 30% at cement replacement levels of 10%, 20%, 30%, 40%,
50%, 60%, 70%, and 80% were then determined.
Source: Adams [10]
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The sites considered for this investigation are the officially approved and government controlled abattoirs and slaughter slabs.
Table 2: Availability of Cow Bone in Lagos State, NIGERIA
Number of cows slaughtered per day 1875
Average weight of a matured cow 400kg
Percentage of bone in a matured cow 20-30%
Total Weight of cows slaughter per
day in Lagos 750,000kg
Percentage of bone generated as waste
per day using the lower boundary of 20% 150,000kg
Annual weight of bone generated
in Lagos State ` 54,750,000kg
(about 55000 tonnes)
1.14%. This value is within the limits of 3.0% set by
BS 12 [8].
The alkalis (K2O and Na2O), with a combined percentage of
2.18% is low, and thus reduce the possibility of the destructive
alkali-aggregate reaction (Neville, [12].
Table 3: Chemical Composition (%) of Ordinary Port- land Cement (OPC) and Pulverized Bone
Source: Adams [10]
The annual generation of cow bones is about 55000tonnes within the Lagos metropolis, excluding those generated unof- ficially by private individuals at weekend parties, rallies, reli- gious festivals, sundry ceremonies, etc, which is definitely a multiple of the official figures. Based on the cow bones genera- tion in Lagos metropolis, the annual national generation of cow bones can be conservatively put at about 5million tones. About two (2) million tonnes of the bones is used for animal feeds and other usage, the remaining three (3) million tonnes can be used for concrete production if found to be suitable, and this no doubt may result in reduction of cost of cement. The three (3) million tonnes is about 30% of the national ce- ment production which Franklin [11] put at 9.5million tonnes (though about 19.5million tonnes of cement is consumed an- nually). This will also serve as way of recycling waste generat- ed from cow meat consumption.
The result of the chemical analysis of pulverised bone car- ried out at the Department of Chemistry, University of Lagos is presented in Table 3. Also its effects on the physical and setting properties of cement paste is presented are Table 4. Figures 1, 2, and 3 are the results of consistency, setting times, and cube tests respectively.
The results of chemical analysis on pulverised bone are pre- sented in Table 3.
From Table 3, it is observed that that the chemical composi- tion of pulverized bone is almost identical to that of the stan- dard Ordinary Portland Cement. The fact that this similarity does not translate to ability to develop cementitious properties when later used in mortar cubes may be due to the presence of fat remnants in the pulverised bone, which seem to be inhibit- ing hydration. The following observations are also made:
Pulverised bone has a high calcium content (over
70%), thus belonging to class C type of fly ash.
The loss on ignition, a measure of the extent of carbo-
nation and hydration of free lime and free magnesia
due to atmospheric exposure, of pulverised bone is
The results of investigation on the influence of pulverised bone on some properties of cement are presented in Table 4. The parameters measured are: specific gravity, consistency, initial and final setting times and compressive strength. From the Table 4 above, the followings can further be observed:
The specific gravity of the paste containing pulverised bone decreases gradually as the percentage of pulverised bone in- creased. Specific gravity decreased from 2.92 (that is, the con- trol - the sample without pulverized bone) to 2.22 for samples without cement (that is 100% pulverised bone). This means that more volume of pulverised bone is required for equiva- lent weight of cement. Also the fact that the specific gravity of control is higher than paste with pulverised bone is an indica- tion higher density. Lower density of paste with pulverised bone is an indication of a porous internal matrix compared with the control.
The water requirement to produce a consistence paste, meas- ured by the water content that produced a paste that allows the Vicat plunger to sink to between 5 and 7mm from the bot- tom of the Vicat mould, determined in accordance with BS 12 [8], reduces as the percentage of cement replacement with pulverized bone increased. That is, less amount of water was required to produce the same level of consistency, as pulve- rized bone content in the mix increased. This trend is shown in Figure 1.
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The use of pulverized bone increased the setting times (initial and final) of cement paste as proportion of pulverised bone content increased up to 30% where the highest retardation of approximately 2 hours and 21/2 hours for initial and final set- ting times respectively occurred. Although the increase dropped beyond 30%, it can still be said to have a retarding influence up to 80% replacement when compared with the control. At 80% replacement, the paste did not set - a re- quirement for strength development. This can be seen in Fig- ure 2. The fact that pulverized bone sets only in the presence of cement, to release calcium hydroxide (CH) during hydroly- sis, is an indication of its pozzolanic traits.
400
350
300
250
200
150
100
50
0
Initial Setting Time (mins)
Final Setting Time (mins)
0 10 20 30 40 50 60 70 80 90 100
Percentage Pulverized Bone Replacement (%)
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0 10 20 30 40 50 60 70 80 90 100 110
Percentage Pulverized Bone (%)
Figure 3 shows the variation of compressive strength of ce- ment-pulverized bone mortar with time. The results indicate that pulverised bone on its own has no cementitious property as the cohesiveness of the mixture containing it weakens with increase in proportion of pulverised bone in mortar mixtures. At 80%, the setting time reduced but the corresponding com- pressive strength was very negligible while at 90% and 100% pulverized bone content, the mixture was no longer setting. This behaviour may be attributed to high pulverized bone content. For all the replacement levels, the strengths of the mixtures increased with age. However, the strength decreased as the percentage of pulverised bone increased. For example, at 28 days curing, the compressive strength increased from
1.10N/mm2 at 80% cement replacement with PB to
35.23N/mm2 at 0% cement replacement with PB. This beha-
viour of pulverised bone indicates that it exhibits pozzolanic characteristic. It is known that by adding pozzolanic material to cement mortar or concrete mix, the strength-forming pozzo-
lanic reaction will only start when calcium hydroxide (CH) is released and pozzolan/CH interaction exist (Villar- Cocina et al., [13]). The more CH that is released, the more will be the pozzolanic activities, and the more will be the amount of the strength-forming calcium silicate hydrate (C-S-H) gel.
Although, the cubes containing pulverised bone have lower
28-day compressive strengths compare to the control, there is
no significant difference between the 28-day compressive
strength for cubes containing 20% percent pulverised bone
and the control. Statistical analysis using the analysis of va- riance and the t- test were performed using t-distribution table to examine the significance of the differences in the 28-day compressive strengths between the control specimens and
specimens containing different level of pulverised bone re- placement (Appendix A). The results showed that provided the replacement of cement does not exceed 20%, there is no significant difference in the 28-day strength of the samples.
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40.0
0% PB
10% PB
20% PB
[1] Yilmaz, K. (2010). ―A study on the effect of fly ash and
silica fume substituted cement paste and mortars‖.
35.0 30% PB
Scientific Research and Essays Vol. 5, Issue 9,
30.0
25.0
20.0
15.0
10.0
5.0
0.0
40% PB
50% PB
60% PB
70% PB
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Curing Age (Days)
pp. 990-998.
[2] Hussin, M. W. and Abdullah, K (2009) ―Properties of Palm Oil Fuel Ash Cement Based Aerated Concrete Panel Subjected to Different Curing Regimes‖. Malay sia Journal of Civil Engineering, Vol. 21, No. 1, pp.
17 – 31.
[3] Givi, A. N., Rashid, S. A., Aziz, F. N. A., Salleh, M. A.
M. (2010). ―Contribution of Rice Husk Ash to the
Properties of Mortar and Concrete: A Review‖. Jour
nal of American Science Vol. 6, No 3, pp. 157 – 165. [4] Wilson, J. W. and Ding, Y. C. (2007). ―A Comprehen
sive Report on Pozzolanic Admixtures, the Cement Industry, Market and Economic Trends and Major Companies Operating in the far East, with reference to Pagan Island‖. A Report Prepared for the Secretary, Department of Public Lands, Common wealth of Northern Mariana Islands, pp. 4-33.
[5] Falade, F. (1990) ―Effects of Sawdust Ash on the Strength of Laterized Concrete‖. West Indian Journal of Engineering, Vol. 15, No. 1, pp. 71 – 84.
From the foregoing, the following conclusions are made:
There is a credible potential for pulverized bone to be used as a pozzolanic material in the production of concrete and its pozzolanic activities, measured by strength development increases with curing age.
The pulverised bone does not contain dangerous
oxides (K2O and Na2O) that have the potential to react destructively with other components of concrete, es-
pecially aggregates, to cause concrete deterioration.
The incorporation of pulverised bone in cement-sand mortar progressively brought about reduction in the
28-day compressive strength when compared to the control sample. But a replacement of not more than
20% can be considered to have a prospect for use in
concrete production, where the strength reduction is
statistically insignificant when compared with the
strength of the control specimens.
The use of pulverised bone resulted in reduction in water required to produce pastes of the same consis- tency as the level of cement replacement by pulve- rised bone increased. The water content to produce
standard consistence was 30% for the control sample, and this reduced progressively up to 20% as the pul- verised bone content increased.
The incorporation of pulverised bone in paste has a
retarding effect, by implication, a delayed cement hy-
dration and delayed early strength development.
Pulverized bone can be classified as ―natural pozzo-
lan‖ because it does not require calcinations before it
can develop pozzolanic characteristics.
[6] Fapohunda, C. A. (2010). ―Effects of Blast Furnace Slag on Chloride Permeability of Concrete Cured at Elevated Temperatures‖. ActaSatech Journal of Life and Physical Sciences, Vol. 3, Issue 2, pp. 119-123.
[7] Salau, M. A. and Olonade, K. A. ―Pozzolanic Poten tials of Cassava Peel Ash‖. Journal of Engineering Research, No. 1, March 2011, pp. 10 – 20.
[8] BS 12 (1996). ―Specifications for Portland Cement‖
British Standard Institution, London, 15th Edition.
[9] BS 4551 (1998). ―Methods of Testing Mortar, Screeds
and Plasters - Part 1‖. British Standard Institu
tion, London
[10] Adams, G. O. (2011). Director, Lagos State Ministry of
Agriculture and Cooperatives, Veterinary Divi
sion, Alausa, Ikeja Lagos. Personal Communication.
[11] Franklin, A. (2009), ―Nigeria: Minister Forecasts 2013
Self Sufficiency in Cement Production‖. Van
guard Newspaper, Nigeria, 26th November, 2009.
[12] Neville, A. M. (2003). ―Properties of Concrete‖. Pear
son Education, 4th Edition.
[13] Villar-Cocin, E., Valencia-Morales, E., GonzalezRod
rıguez, R., and Hernandez-Ruız, J. (2003) ―Kinetics of
the pozzolanic reaction between lime and sugar cane straw ash by electrical conductivity measurement: A kinetic–diffusive model‖. Cement and Con crete Research, Vol. 33, No. 4, pp. 517–524.
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Difference in Strength
% PB | 28-day Strength of 3 Cubes | Mean | S.D | t-test | ||
1 | 32.80 | 27.60 | 30.29 | 30.23 | 2.6005 | |
10 | 26.00 | 23.90 | 22.03 | 23.98 | 1.9861 | -5.453 |
20 | 18.70 | 19.10 | 21.15 | 19.65 | 1.3143 | -5.702 |
30 | 13.10 | 14.20 | 13.35 | 13.55 | 0.5766 | -18.32 |
40 | 8.62 | 8.01 | 8.00 | 8.21 | 0.3551 | -26.05 |
50 | 4.00 | 3.98 | 4.32 | 4.10 | 0.1908 | -37.31 |
60 | 3.62 | 3.45 | 3.43 | 3.50 | 0.1044 | -9.954 |
70 | 2.34 | 2.42 | 2.44 | 2.40 | 0.0529 | -36.01 |
80 | 1.10 | 1.09 | 1.11 | 1.10 | 0.01 | -225.2 |
Assuming a 2-tailed confidence level of 2%, the critical val- ue is ±6.965
The difference between the control and up to 20% replace- ment level is not to be considered significant.
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