Description
CHAPTER ONE
1.0 INTRODUCTION
Concrete is a composite element consisting of aggregates enclosed in a
matrix of cement paste including possible pozzolanic, has two major
components-cement paste and aggregates. As a construction material, concrete
can be in almost any shape desired, and once hardened, can become a structural
(load bearing) element. The strength of concrete depends upon the strength of
these components, their deformation properties, and the adhesion between the
paste and aggregate surface. With most natural aggregates, it is possible to make
concrete up to 120KN/mm 2 a compressive strength by improving the strength of
the cement paste, which can be controlled through the choice of water-cement
ratio, and type and dosage of admixtures (Dwivedi 2006).
The high cost of conventional construction material is a dominating factor
affecting housing system around the world. This has necessitated research work
into alternative materials in the construction field. Since the cost of cement is
many times more than the cost of other ingredients in concrete making.
Recently, attention is mainly directed to use of as little cement as possible
constituent with adequate strength and durability. Little research has been
carried out to study the bamboo leaf waste as a pozzolanic material. Dwivedi
(2006) reported the reaction between calcium hydroxide (CH) and bamboo leaf
ash for four hours of reaction using the differential scanning calorimetric (Dsc)
technique. Singh et al (2000) discussed that eco friendly composite cements
may be obtained by partial replacement of Portland cement (PPC) with low cost
materials. They studied the hydration of bamboo leaf ash in a blended Portland
cement. It was concluded that bamboo leaf ash is an effective pozzolanic
materials. When 20 weight (wt) % of bamboo ash was mixed with PPC the
compressive strength values of mortars at 28 day of hydration were found to be
quiet comparable to those of PPC. Villar-cocina et al (2010) conducted a study
on sugarcane leaf ash (SCLA). Hydration of 10 wt % SCLA composite Portland
cement was studied by using powder x-ray diffraction, FTIR spectroscopy, and
differential scanning calorimetric and other techniques. The result have show
that the pozzolanic reaction of sugarcane leaf ash increases with time. They
have been used to produce concrete having almost the same behavior as normal
concrete.
In general, a pozzolanic material has little or no cementing properties.
However, when it has a fine particle size, in the presence of moisture it can react
with calcium hydroxide at ordinary temperatures to provide the cementing
property. Bamboo leaf ash (BLAsh) is one of the agro waste ashes whose
chemical composition contains a large amount of silica and has high potential to
be used as a cement replacement (Okere 2013). Most of the concrete produced
today are a multi component product containing one or more admixtures in
addition to the four basic components which is cement, fine aggregate, coarse
aggregate and water. For every component, one usually as several choices that
could influence the cost of the end product and its behavior in service. Among
the constituent components, however, cement or cementitious materials as a
whole, play a vital role in producing strong and durable concrete. Utilization of
these waste materials is a partial solution to environmental and ecological
problems. Use of these also helps in reducing the cost of concrete production by
reducing the quantity of cement used. Consequently, this study presents the
suitability of using bamboo leaf ash (BLAsh) as a supplementary cementitious
material. This work then investigates the effect of bamboo leaf Ash on the
workability of fresh concrete and the compressive strength of added concrete.
1.1 STATEMENT OF THE PROBLEM.
Concrete plays an important role in the beneficial use of the material in
construction industry. Many modifications and developments have been made
to place material like Bamboo Leaf Ash (BLAsh), wood wool, rice husk and
marble powder as a cement replacement constituent, but it as an alternative to
reveal that the replacement of Bamboo Leaf Ash (BLAsh), in Portland cement
affect the compressive strength of concrete. One of the main goal of sustainable
waste management is to maximize recycling and reuse. With increasing
environmental pressure to reduce waste and pollution and to recycle as much as
possible, the concrete industry has begun adopting a number of methods to
achieve these goals.
One of the suggestions in the forefront has been the sourcing,
development and use of alternative, non-conventional local construction
materials including the possibility of using some agricultural wastes and
residues as partial or full replacement of conventional constructional materials.
In countries where abundant agricultural wastes are discharged, these wastes
can be used as potential material or replacement material in construction
industries.
This has a significant impact by reducing the amount of quarrying and landfill
space required, and acts as a cement replacement, reduces the amount of
cement of required to produce a solid concrete. As cement production creates
massive quantities of carbon dioxide, cement replacement technology such as
this will play an important role in future attempts to cut carbon dioxide
emissions and production of economical optimum strength concrete, so as to
encourage the use of this ‘impressive’ waste product as construction material in
low-cost housing.
1.2 AIM AND OBJECTIVES
The aim of this project is to study the compressive strength of concrete
with cement partially replaced with bamboo leaf ash and the suitability of the
material to be used as cement substitute
The objectives of the projects are:
To determine the percentage of BLAsh as a replacement for cement of
5%,10%,15%,20%.
To replace cement with known percentage of bamboo leaf ash and cast
with it.
To examine the workability of the fresh BLAsh concrete by slump test.
To compare the strength of cubes cast at 100% of cement with cubes
replaced with the known percentage of bamboo leaf.
To suggest the use of bamboo leaf ash as alternative supplement to
cement so as to reduce cost of construction.
1.3 JUSTIFICATION OF THE STUDY.
In Nigeria today, an appreciable percentage of the entire population
cannot afford to build their own houses especially modern types due to high cost
of cement and the average percentage of the country’s population find it
difficult or almost impossible to afford the cost. In order to curb this act, this
project is targeting whether bamboo leaf ash can be used as a partial
replacement for cement in order to achieve optimum strength and economic
concrete and the corresponding quantity of coir ash required.
1.3 SCOPE AND LIMITATION OF WORK
This study concentrated on investigation of compressive strength of
bamboo leaf (BLAsh) concrete and pure cement (100% of cement) as a control
sample. The Laboratory Tests include sieve Analysis, specific gravity natural
moisture content and water absorption of each aggregate sample. Each samples
of concrete were design for grade 20 (as mix ratio 1:2:4) and water cement ratio
(w/c) of 0.55. The control sample composed of 100% cement, fine Aggregate,
coarse aggregate and water. Then, other four samples were of the same mix
design with bamboo leaf ash as cement replacement that serves as an
Unconventional mixes which comprises of 5%, 10%,15% and 20% of the total
weigh of ordinary Portland cement. These specimens (samples) were the
comprehensive strength test with the use of Universal Testing Machine in
accordance with BS1881:Part1:1983.
1.4 METHODOLOGY.
In carrying out of the research work, the method adopted is in this
sequence.
– Procurement of materials.
– Preparation of the bamboo leaf Ash.
– Testing of the materials.
– Casting of the cubes.
– Curing of the cubes.
– Testing for the compressive strength of the specimen.