BAMBOO LEAF ASH (BLA) AS A PARTIAL SUBSTITUTE FOR CEMENT
HOUNSINOU B.B., NWANGOH A.O., OREKOYA T.O., OMOTAYO T.S., KOTUN M.O.
Department of Civil Engineering, Yaba College of Technology, Yaba, Lagos State
Email: [email protected]
Tel: 08171026180, 09076332900
This aims and objectives of this research are aimed at ascertaining the possibility of using Bamboo Leaf Ash (BLA) as a partial substitute for cement to reduce cost in construction works. This possibility to ascertain the use of the bamboo leave ash as a concrete supplement was determined by the flow and compressive strength of the concretes created by this Bamboo leaf ash. The slump was determined in the laboratory after well planned and mapped out practical, while the compressive strength was done on a 150 by 150 by 150mm cubes. The cubes were cured between 7 to 28 days. Twenty cubes were casted in the cube moulds to assess the strength of the Bamboo leave ash in the concrete with one sample for each batch and the replacement of cement by percentages, which include 0%, 5%, 10%, 15%, and 20%.
Water cement ratio of 0.5 was used to produce the blended concrete of mix 1:2:4.
The research showed that as the percentage of BLA supplement increased the slump required less water to be stable and workable.
The compressive strength of the blended concrete reduced exponentially at 5% of the supplement and appreciated to 20%.
Pozzolans are building materials, which can be used, in various building works and jobs due to its ability to atrophy with cement and cement materials. Pozzolans are silicate-based materials that react with (consume) the calcium hydroxide generated by hydrating cement to form additional cementitious materials. They are usually a broad class of siliceous and aluminous materials which, in themselves, possess little or no cementitious value but which will, in finely divided form and in the presence of water, react chemically with calcium hydroxide at ordinary temperature to form compounds possessing cementitious properties. The measurement of the capacity of a pozzolan to react with calcium hydroxide and water is determined and obtained by measuring its pozzolanic activity. Pozzolana is a naturally occurring pozzolan of volcanic origin.
Mixtures of calcined lime and finely rounded, active aluminosilicate materials were pioneered and developed as inorganic binders in the Ancient world. Architectural remains of the Minoan civilization on Crete have shown evidence of the combined use of slaked lime and additions of finely ground potsherds for waterproof renderings in baths, cisterns and aqueducts. Evidence of the deliberate use of volcanic materials such as volcanic ashes or tuffs was first traced to the ancient Greeks which dates back to roughly 500 – 400 BC, as uncovered at the ancient city of Kameiros, Rhodes. In subsequent centuries, the practice spreaded to the mainland and was eventually adopted and further developed by the Romans. The Romans used volcanic pumices and tuffs found in neighboring territories, the most famous ones found in Pozzuoli (Naples), hence the name pozzolan, and in Segni (Latium). Preference was given to natural pozzolan sources such as German trass, but crushed ceramic waste was frequently used when natural deposits were not locally available. The exceptional lifetime and preservation conditions of some of the most famous Roman buildings such as the Pantheon or the Pont du Gard constructed using pozzolan-lime mortars and concrete testify to both the excellent workmanship reached by Roman engineers and to the durable properties of the binders used.
The cumbrous cost of building materials is observed to be one of the major factors affecting the construction industry in Nigeria in the delivery of a stable building structure in Nigeria. This has been partly traced to the increasing cost of cement; which is mostly used in the production of Sand-Crete blocks, concrete and stabilizing admixture in soil blocks. Furthermore, there are also issues arising in the production processes of cement which ranges from high energy consumption to very large emission of CO2; a major greenhouse gas which is poisonous to the human health. Hence, for an underdeveloped country which is faced with an unstable energy source and with the global campaign against the emission of greenhouse, gasses to curb Global Warming, it is only appropriate to seek alternatives in the use of cement in the effort of achieving the goal of quality assured building structures. All around the world, Pozzolans are famed in its ability to be a viable substitute for cement, especially in the realm of partial replacement. Pozzolans are fine silica and alumina rich materials which when mixed with hydrated lime produces a cementitious material suitable for stabilization and constructional needs. Recently, it was reported that BAMBOO LEAF ASH is an equally good pozzolanic material which reacts with calcium hydroxide to release additional calcium silicatehydrate(C-S-H); the main cementitious component (Dwivedi et al., 2006).
Much of the practical skills and knowledge regarding the use of pozzolan was lost during the fall of the Roman empire. The rediscovery of Roman architectural practices as described by Vitruvius in De architechtura, also led to the rebirth of lime-pozzolan binders. Particularly the strength, durability and hydraulic capability of hardening underwater made them popular construction materials during the 16th–18th century. The invention of other cements, which could harden under water and eventually the advent of Portland cement in the 18th and 19th century resulted in a gradual decline of the use of pozzolan-lime binders, which develop strength less rapidly.
The chemical composition of BLA in comparison with Ordinary Portland Cement (OPC), while tests to determine the pozzolanicity of BLA such as determination of liquid phase of Ca2+ and pozzolanic reactivity in suspension at a varying temperature of 30oC and 75oC
(I.O. Olofintuyi et al 2012)
Laterite is the commonly used as a building material in rural areas in Nigeria. It has been noted that it became the traditional building construction material due to its relative availability, economic processing cost and ease of handling with little or no equipment and skill requirements. However, studies have shown that lateritic soils are generally weak in compression and tend to absorb moisture and become soften. Consequently, walling materials such as lateritic blocks has been the subject of investigation for decades; partly, to serve as an alternative to the conventional sand Crete blocks. Such effort is especially desirable, as it is well known that the production processes of cement; which is the main binder employed in the production of sand Crete blocks is associated with huge energy consumption and emission of harmful gases such as CO2. (F.A Olutoge. et al., 2017).
Over the course of the 20th century the use of pozzolans as additions (the technical term is “supplementary cementitious material”, usually abbreviated “SCM”) to Portland cement concrete mixtures has become common practice. Housing for the poor remains a major challenge for most developing nations like Nigeria where majority of the populations live in sub-standard houses. According to (Anthonio, 2003), housing is an essential component in human existence that ranks comparably with the provision of food and clothing in the hierarchy of the basic primary elements required for human existence. At its most primary level, it addresses the basic human needs by serving as shelter, protection against excessive weather conditions as well as protection against unwanted aggressions.
As observed by Mustapha (2004), homelessness and the incidence of people living in poor housing and unhealthy neighborhoods are rapidly growing. The housing problem is acute especially in the urban areas due to shortage of affordable housing for low-income earners and the poor who constitute over 70% of the urban population
The benefits of pozzolan use in cement and concrete are of three benefits. First is the economic gain obtained by substituting a substantial part of the Portland cement with the pozzolan, pollution free, naturally abundant either in the physical environment or as by-products of industries. Second is the lowering of the blended cement environmental cost associated with the green house gases emitted during Portland cement production and processing. A Third merit is the increased durability of the end product.
AIM & OBJECTIVES
The aim of this work is to partially substitute bamboo leaves ash (which is usually gotten from bamboo leaves after being burnt) for cement in construction.
The objectives are:
a) Supplementing Cement with Bamboo Leaf Ash (BLA) in specific range of percentages (0%, 5%, 10%, 15% and 20% e.t.c.)
b) Ascertaining the Compressive Strength of the material supplemented with Bamboo Leaf Ash (BLA) at their specific percentages in comparism with those materials made without substitutin.
3.0SCOPE OF STUDY
The scope of study of this project is to know to what degree Bamboo Leaf Ash (BLA) can be used to supplement cement due to its pozzolanic characteristics, which has been established research through years of by other researchers.
Description of Work
This Work Is Aimed At Ascertaining The Possibility Of Using Bamboo Leaves Ash Which Are Common Waste Materials In Nigeria As A Pozzolanic Materials To Suppliment Cement In Construction..4.1SAMPLE MATERIALS
During this research the sample materials used are:
Bamboo leaf ash (BLA)
The bamboo Leaves (Fig. 1) used were fetched at Idi-Oparun, Oreyo, Igbogbo, Ikorodu, and Abesan Estate, Ipaja, Lagos State, Nigeria.
1600202472055They were sun-dried and later burnt in a KILN at temperature of 500°C or 773°K calcining temperature for two hours at The Federal Institute of Industrial Research, Oshodi (FIIRO) to obtain the ash to be used for the research at Yaba College of Technology. Bamboo leaf ash (Fig. 1.1) can serves as a cementitious material and at the same time serve as stabilizer in soil stabilization processes.
Fig 1.0: Bamboo Leaf Ash and Freshly Harvested Bamboo Leaves
B. Aggregate (Coarse-Fine Aggregates)
The remaining ingredient of concrete, beside the cement and water, is the Aggregate (which could be sand, broken stone or rubbles, cenders, slag etc.), which are chemically inert. Any aggregate less than 6.35mm in diameter is designated as FINE AGGREGATES and generally refers to SAND, Aggregates above 6.35mm in diameter are called COARSE AGGREGATE and includes the Granite, Broken Stone, Cinder etc. Any crushed rock or slag of durable character or any clean, impervious, natural gravel can be used as a coarse aggregate. Granite, trap rock or hard limestone are preferable and are prepared in quarries for such use. They are crushed and screened to adopted sizes, so that the aggregates may be exactly graded by sieve analysis.
Ordinary Portland Cement (OPC) was used during research, as it is a main constituent in the project. The cement in question is to be replaced partially by a substantial amount of Bamboo Leaf Ash (BLA). The OPC was bought from the cement vendor or dealer. Each bag of the cement is 50kg mass in size. Some of the properties required of this cement are as follows:
(i) Good initial setting time, which must not be more than Forty-five (45) minutes.
(ii) A very Suitable Final setting time must not be more than ten (10) hours.
(iii) The compressive strength test of concrete cube made from the BLA after twenty-eight (28)days must have a value of not less than 25N/mm2.
The water sourced for this work study was from the Soil Mechanics Laboratory situate at the Department of Civil Engineering Yaba College of Technology, Lagos. The water was free from impurities (i.e. injurious amount of oil, acid, organic matter, alkali and other deleterious substances e.t.c).
The method and procedure used in this research was experimental. It involved field and laboratory tests, which included:
Compressive Strength test
5.1COMPRESSIVE STRENGTH TEST METHOD
The compression test was carried out to determine the compressive strength of the concretes. For compressive strength, cubes of 150 by 150 by 150mm are cast from the reference mix of SCC & NVC and kept for different types of curing up to 28 days. The specimens are tested after 7, 14, 21 and 28 days as regards the IS:516-1959 200459 regulation, using a calibrated compression testing machine of 2,000KN capacity. An operational stage of the compression test is shown in Fig. 1.2
After cleaning the bearing surface of the compression-testing machine, the concrete cube was placed on its smooth face side. The axis of the specimen was carefully aligned with the center of the lower pressure plate of compression testing machine. No packing used between face of the pressure plates and cube.
The compression was applied and the maximum or ultimate load carried by the specimen was recorded. The compressive strength was calculated based on the ultimate load and the cross-sectional area of the cube. Average of three values was taken for determining compressive strength of concrete
Fc = P / A
P= Ultimate load in N
A= Area of cube in mm2
Number of Specimens for each Mix
In this work study, a cube was cast for each Ordinary Portland Cement as a control mix and for each replacement by BLA. Therefore, for each batch, total numbers of four (4) 150mm cubes were cast, one specimen was tested for each stage in a particular mix for a particular amount of days (i.e. the cubes were crushed at 7, 14, 21 and 28 days respectively). All freshly, cast specimens were left in the molds for 24 hours to dry and congeal before being demolded and then submerged into water for curing until it was time to be tested.
Since the quantity of molds required was large, wooden molds of size 150 mm by 150mm by 150mm was constructed to cast the entire specimen in one day. Table 1 shows the age of the different test conducted in the research, the specimen used and the number of the specimen for each mix.
Test AGE (Days)
7 14 21 28
Number of Specimen BLA 00/0 1 1 1 1
BLA 5 0/0 1 1 1 1
BLA 100/0 1 1 1 1
BLA 150/0 1 1 1 1
BLA 200/0 1 1 1 1
Mix Proportions of Concrete Specimens
Proportioning by weight method was applied in determining the physical density and strength of concrete because it was found to be more accurate and precise than the proportioning by volume method. The ratio of cement to dried total aggregates used in this work was 1:2:4. Bamboo leaf ash was substituted for the Portland cement at doses of 0%, 5%, 10%, 15% and 20% by weight of the binder. The mix proportions were calculated as follows:
No. of Cubes per Batch = 4
Volume of cube = Length x Breadth x Height
= 0.15 x 0.15 x 0.15
= 3.375 x 10-3m3
Density = Mass/Volume
Mass= Density x Volume
Mass= 2,400 x 3.375×10-3
Wastage of 5% = 0.405kg
Total mass for a cube= 8.1 + 0.405
Total mass for 4 cubes = 8.51 x 4
The ratio used in this research is
Cement: Fine Aggregate: Coarse Aggregate.
Cement = 1/1+2+4 x 34.04= 4.86kg
Water Cement Ratio (0.5)= 0.5 x 4.86= 2.43Litres
Fine Aggregate= 2/7 x 34.04= 9.73kg
Coarse Aggregate= 4/7 x 34.04= 19.45kg
For 0% Control
Cement = 4.86kg
Fine Aggregate = 9.73kg
Coarse Aggregate = 19.45kg,
Water Cement Ratio (0.5)= 2.43L
For 5% of BLA in Cement
Cement = 4.62kg, BLA= 0.24kg,
Fine Aggregate = 9.73kg,
Coarse Aggregate = 19.45kg,
Water Cement Ratio (0.5)= 0.5 x 4.62= 2.31L
For 10 0/0 of BLA in Cement
Cement = 4.37kg, BLA = 0.49kg,
Fine Aggregate = 9.73kg,
Coarse Aggregate = 19.45kg,
Water Cement Ratio (0.5)= 0.5 x 4.37= 2.19L
For 150/0of BLA in Cement
Cement = 4.13kg, BLA = 0.73kg,
Fine Aggregate = 9.73kg,
Coarse Aggregate = 19.45kg,
Water Cement Ratio (0.5)= 0.5 x 4.13= 2.06L
For 200/0of BLA in Cement
Cement = 3.99kg, BLA = 0.97kg,
Fine Aggregate = 9.73kg,
Coarse Aggregate= 19.45kg
Water Cement Ratio (0.5)= 0.5 x 3.99= 2.00L
Total material required
BLA = 2.43kg
Cement = 21.97kg
Fine Aggregate = 48.65kg
Coarse Aggregate = 97.25kg
Water = 10.99L
SLUMP FLOW TEST
The slump flow was mainly made to assess the horizontal free flow of Self-Compacting Concrete (SCC) in the absence of hindrances. It was first made in Japan for use in assessment of underwater concrete works. The diameter of the concrete circle is a measure for the filling ability of the concrete.
Assessment of test: This is a simple, rapid test procedure, though two people are needed if the T50 time is to be measured. It can be used on site, though the size of the base plate is somewhat unwieldy and level ground is essential. It is the most commonly used test, and gives a good assessment of filling ability. It gives no insight of the ability of the concrete to pass between reinforcement without blocking, but may give some insight of resistance to segregation. It can be argued that the completely free flow, unrestrained by any boundaries, is not representative of what happens in practice in concrete construction, but the test can be profitably Methodology
2476501437640Effect of curing techniques on mechanical properties of self-compacting concrete 119 of ready-mixed concrete to a site from load is used to assess the consistency of supply to load.
The apparatus is shown in fig. 2.2 & 2.1 above: Slump flow test apparatus
Base plate of a stiff non-absorbing material, at least 700mm2, marked with a circle marking the central location for the slump cone, and a further concentric circle of 500mm diameter.
A slump cone specified in JIS A 1101 (Method of test for slump of concrete) shall be used.
The plate shall be made of steel and sufficiently watertight and rigid. It shall be
Approximately 0.8 m by 0.8 m or larger in size and shall have a smooth surface. Handles, if
Required, shall be installed where they do not obstruct the slump flow measurement.
For measuring slump flow, calipers or a measuring scale2 and guides3 as shown in Fig. 1 shall be used.
The test can be done in two (2) ways and About 6 liter of concrete is needed to perform the test, sampled normally.
Moisten the base plate and inside of slump cone, Place base plate on level stable ground and the slump cone centrally on the base plate and hold down firmly.
Fill the Cone in quarters (1/4) and tamper each with 25 blows.
Scrape off the excess concrete from the top to level it off and remove those around the cone to avoid obstruction of flow.
Gently remove the cone to allow the concrete slump.
Measure the height of the slump.
Calculate the difference in height between the slump and the Cone (this is the slump in mm).
Fill the cone with the scoop. Do not tamp, simply strike off the concrete level with the top of the cone with the trowel.
Remove any surplus concrete from around the base of the cone. Raise the cone vertically and allow the concrete to flow out freely.
Simultaneously, start the stopwatch and record the time taken for the concrete to reach the 500mm spread circle. (This is the T50 time).
Measure the final diameter of the concrete in two perpendicular directions.
Calculate the average of the two measured diameters. (This is the slump flow in mm).
Note any border of mortar or cement paste without coarse aggregate at the edge of the pool of concrete.
Volume of Frustrum= ?h/3 (R2 + Rr + r2)
R= 100mm = 0.1m
r= 50mm = 0.05m
h= 300mm = 0.3m
= 3.142 x 0.3/3 (0.12 + 0.1 x 0.05 + 0.052)
Volume= 0.0055 m3
Density= Mass / Volume
Mass= Density x Volume
Mass= 2,400 x 0.0055
Mix ratio= 1:2:4
Cement: Fine Aggregate: Coarse Aggregate.
Cement = 1/7 x 13.2
Water Cement Ratio= 0.5 x 1.9
Fine Aggregate= 2/7 x 13.2
Coarse Aggregate= 4/7 x 13.2
RESULTS AND DISCUSSION
Two test were carried out to achieve the Aim of this research and they are:
To test the flow rate of a self compacting concrete usually on an horizontal plane
Compressive Strength Test
The compressive test is usually done to ascertain the maximum Load the concrete can withstand (i.e. strength of the concrete).
The Results of which are given below
The Slump Test of the Concrete was carried out on each of the Five (5) sets of Bamboo leaf ash across their different percentages to test the flow
This Test was carried out at the Soil Mechanics Laboratory at Yaba College of Technology, Yaba, and Lagos State.
SLUMP TEST RESULT
Slump Test per (%) of Specimen Average (mm)
BLA 00/0 30
BLA 5 0/0 20
BLA 100/0 19
BLA 150/0 50
BLA 200/0 50
DISCUSSION ON SLUMP TEST
As observed from Graph above, the percentage of supplement increased, as the difference in height between the Top of the cone and the slump(per average mm) increased except at BLA5% -20mm and BLA10% -19mm where there was a decline in the values and lastly we see that the Slump was highest at the highest percentage of Supplement.
COMPRESSIVE STRENGTH TEST
Compressive Strength Test of the Concrete was also carried out on each of the Five (5) sets of BLA supplement across their different percentages. This was to ascertain the maximum load (Force) each of the Cubes can withstand or at which they will Fail.
This Test was carried out Lagos Sate Materials Testing Laboratory, Berger, Lagos State.
COMPRESSIVE STRENGTH RESULT
Test AGE (days)
7 14 21 28
Compressive Strength of Specimen
(N/mm2) BLA 00/0 18.83 18.01 15.28 17.51
BLA 5 0/0 12.27 14.73 11.61 14.92
BLA 100/0 10.59 12.33 12.00 11.67
BLA 150/0 11.95 11.90 12.42 13.27
BLA 200/0 12.24 9.27 10.29 10.92
DISCUSSION ON COMPRESSIVE STRENGTH TEST
What was observed was that the Average Strength per percentage of BLA dropped Drastically on each of the cubes according to the days of curing from 4.02N/mm2 to 6.59N/mm2.
The level at which the values for slump test reduced from the 30mm for the 0% BLA (Control) to 50mm for the 20% BLA was still very moderate and can as well be said to have passed the test for flow, as it didn’t exceed 90mm.
However the initial decline of 6.56N/mm2 in the Strength of the concrete from 0%BLA (Control) to 5%BLA after 7 days, and an Average decline of 4.02N/mm2 across all the days, Considering the fact that 5% is the least Percentage of the supplement is one (1) which makes N/mm2 negligible, as the 5% BLA didn’t put up enough resistance.
And then an initial decline of 6.59N/mm2 in the Strength of the concrete from 0%BLA (Control) to 20 %BLA after 7 days and an Average decline of 6.72N/mm2 across all the days, also recalling that 20% is the highest percentage of the supplement, just followed the trend of the 5% BLA Supplement by still not putting up enough resistance to increase the strength of the concrete to a considerable level
Bamboo Leaf Ash was not convincing in its ability to reduce the amount of cement to be used but still maintains the strength to an acceptable degree as well as it reduces cost.
A constant water cement ratio must be maintained throughout the mix of the different percentages, if otherwise it should be stated.
Additives should be used in order to increase the compressive strength of the BLA.
It should be kept in a dry place to avoid weather attack which may reduce its strength
Ensure the Compressive Strength machine has been calibrated not less than 360 days before its use soo as t function properly.
Casting should be done very close to the laboratory where the cubes are to be crushed (Strengths are to be tested) to ensure a more accurate result
Effort should be made to keep BLA Sealed after burning and heating to prevent hygroscopy.
Ensure the Cubes are adequately sundried before crushing to achieve accurate result
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Mustapha, Z. (2004).
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Olutoge F.A., Oladunmoye O.M (2017)
Bamboo Leaf Ash as Supplementary Cementitious Material. Department of Civil Engineering Faculty of Technology University of Ibadan, Ibadan, Nigeria.
Olofintuyi I.O., Oluborode K.D., Adegbite I (2015).
Structural Value of Bamboo Leaf Ash as a Pozzolanic material in a Blended Portland Cement, Civil Engineering Department, Federal Polytechnic Ado-Ekiti, Ekiti State, Nigeria. (9) pp4.
KLIN USED FOR THE BURNING OF THE BAMBOO LEAVES FOR THE DERIVATION OF THE BAMBOO LEAVE ASH (B.L.A)
ELECTRICAL WEIGHING BALANCE USED TO WEIGH THE CASTED CUBES
CONE PENETROMETER TESTING MACHINE
COMPACTION STRENGTH MEASURING MACHINE 1
COMPACTION STRENGTH MEASURING MACHINE 2
SLUMP TEST MACHINE
SLUMP TEST MACHINE CONE
COMPRESSIVE STRENGTH MACHINE 3
CRUSHING MACHINE FOR TESTING OF THE CUBES