Ijisme 2018
Ijisme 2018
Ijisme 2018
Abstract: Lightweight concrete (LWC) is a specific type of several classifications of lightweight concrete depending,
concrete developed when the need to reduce dead load becomes either on their method of production where we have
relevant in structures, such as high-rise buildings and bridge lightweight aggregate concrete, aerated or cellular concrete,
decks. This type of concrete can offer a good strength to weight and No-fines concrete; or on the purpose for which the
ratio, good insulating properties and costs benefits due to reduced
sections of bearing elements in a structure (columns, beams,
concrete is to be used, where we distinguish structural
foundations). It is commonly made using artificial lightweight lightweight concrete, concrete used in masonry units and
aggregates like expanded shales and clays; however, the insulating concrete.
manufacturing process of those aggregates is linked to a great Structural lightweight aggregates concrete is a specific type
amount of energy consumption, natural resources depletion, and of lightweight concrete, made with lightweight aggregates
large amount of emission of CO2 gas in the environment, and conforming to the requirements of ASTM C330 standard, and
finally high costs. This experimental study investigated the use of
strong enough to be used as structural concrete. Lightweight
volcanic scoria aggregates from Lukenya in Kenya to produce
structural lightweight aggregates concrete (SLWAC). Scoria aggregates can be artificially processed by expanding, or
stones were collected, crushed into particle sizes 4.75-19 mm, calcining diverse products such as shale, slate, blast furnace
conforming to the grading requirements of ASTM C330, and used slag, clay, or diatomite. The resulting product is called
to produce lightweight concrete designed using the three different artificial lightweight aggregates which are the most
methods prescribed by the standard ACI 211.2-98 for commonly known. However, we also have naturally occurring
proportioning structural lightweight concrete. The design lightweight aggregates such as pumice, tuff or scoria
strength was 30 MPa and the aim was not only to investigate the aggregates [1], [11]. Their physical properties are almost
feasibility of producing structural lightweight concrete with
similar to the artificial aggregates, but with lower mechanical
locally available scoria aggregates, but also to find out the best
mix design approach out of the three prescribed by the standard, properties [3]. For this reason, the production of structural
namely the weight method, the absolute volume method and the lightweight aggregate concrete has been long commonly done
damp loose method. Physical and mechanical tests were carried using the artificial lightweight aggregates even if the
out on the scoria aggregates to classify them as suitable for manufacturing process is related to many environmental
structural lightweight concrete production. Similar tests were also issues such as depletion of natural resources, great amounts of
carried out on the lightweight concrete. The results showed that energy consumption, and emission of dangerous gases (such
the absolute volume method of mix design was the one giving the as CO2); and finally, aspects of high costs.
best results as regards to the dry density, the slump, and the
In Africa, like various other parts in the world, there are a
strengths (compressive, splitting tensile and flexural strength);
This lead to the conclusion that volcanic scoria can be used as an lot of natural resources from volcanic eruptions which are
alternative to artificial lightweight aggregates for structural almost waste, including volcanic scoria aggregates. Scoria is
lightweight concrete production, and proved the efficiency of the relatively darker and heavier than other natural lightweight
absolute volume method as the best mix design approach. aggregates and mostly used by cement companies to make
Keywords: Absolute Volume Method, Artificial Lightweight clinker for cement production, around the world. The other
Aggregates, Lightweight Concrete, Structural Lightweight common use is in road construction where it can constitute the
Concrete, Volcanic Scoria Aggregates sub-base material. However, they are light and porous like
artificial aggregates with many other similar properties. It can
I. INTRODUCTION therefore be used as a cheaper alternative. The advantage of
lightweight aggregates (LWA) as compared to the normal
The use of Lightweight concrete (LWC) has been weight aggregates (NWA), is through conferring to the
investigated in the construction industry for centuries and concrete a lower density (around 25% lighter), leading to size
currently, good performance is expected for a consistent and reduction of load bearing elements in structures, as well as
reliable material with predictable characteristics. There are less structural steel reinforcements. Induced seismic loads are
also decreased, thereby reducing the risk of damages due to
Revised Version Manuscript Received on March 10, 2018.
earthquakes on the structure. Finally these advantages, lead to
Msc. Student, Tejiona Tangomo Frank Roland, Department of Civil cost savings [7], [8], improves sound and thermal insulation,
Engineering, Pan African University Institute for Basic Sciences Technology as well as fire resistance [6], [9].
and Innovation (PAUSTI) hosted by Jomo Kenyatta University of There are very few published studies on the use of scoria
Agriculture and Technology (JKUAT), Juja, Kenya, E-mail:
tejionafrank@gmail.com
as aggregates for structural lightweight concrete production;
Dr. Ochieng Abuodha Silvester, Department of Civil Engineering, most of the previous studies were on the use of lightweight
University of Nairobi, Nairobi, Kenya, E-mail: sochieng@yahoo.com aggregates for production of blocks [10].
Prof. Shitote Stanley Muse, Department of Civil Engineering, Rongo
University, Rongo, Kenya, E-mail: shitote@hotmail.com
Dr. Poh’sié Guillaume Hervé, Department of Civil Engineering, Higher
National School of Public Works, Yaoundé, Cameroon, E-mail:
pguillaumeherve.ing@gmail.com
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Properties of Lightweight Concrete made with Volcanic Scoria from Kenya, as Coarse Aggregates
This study investigated the feasibility of using locally B. Natural River Sand
available volcanic scoria aggregates for production of The sample sand used in this study was from Meru river in
structural lightweight concrete. The volcanic scoria Kenya. This sand has a fineness modulus of 2.32 with
aggregates were prepared and their properties checked in particles sizes between 0-4.75 mm. The sand equivalent value
accordance with the ASTM C330 requirements. Thereafter, and silt content value have been found respectively as 94.77%
three different methods of mix design as prescribed by ACI and 5.42%. Its particle size distribution has been determined
211.2 standard (Weight method, absolute volume method and as shown in Table IV, as well as its bulk density, specific
damp loose method) were used to design lightweight concrete gravity and water absorption summarized in Table V. Its
specimens [2], [4]. Physical and mechanical tests were carried grading curve is shown on Figure I. The sand used was found
out on both scoria aggregates and concrete in a fresh and suitable to produce hydraulic concrete as regard to its
hardened state such as slump, dry density, compressive properties and according to criteria requirements of ASTM
strength, splitting tensile and flexural strength. The aim was to C330.
develop a structural lightweight concrete made with locally
available scoria aggregates while finding out the best mix C. Volcanic Scoria Aggregates.
design approach regarding the requirements of ACI 211.2 The volcanic scoria aggregates were obtained from a quarry
standard. for cement companies in the location of Lukenya in Kenya, in
the form of stones. Subsequently, they were manually crushed
II. MATERIALS into particles sizes 4.75-19 mm. Its particle sizes distribution
met the grading requirements as shown in Table IV. The
The main constituent materials of this study were Ordinary
grading curve is shown in Figure II. Its chemical composition
Portland Cement 42.5, natural river sand as fine aggregates,
was determined as shown in Table III, as well as the other
the volcanic scoria aggregates as coarse aggregates and
physical properties including bulk density (loose and
Water. They are all locally available in Kenya, and the
compacted), specific gravity and water absorption as
research was conducted at the Structural and Materials
summarized in Table V. The properties make them suitable
Laboratory of Jomo Kenyatta University of agriculture and
for lightweight aggregates for structural concrete production
Technology (JKUAT).
according to the criteria requirements of ASTM C330.
A. Ordinary Portland Cement.
Table III: Chemical Composition Volcanic Scoria.
The cement used was Ordinary Portland Cement Type I
(CEM I 42.5 N) called “Bamburi Power Plus”. It is an early Parameters Percentage (%)
high strength cement, conforming to the specification SiO2 72.755
prescribed by the standard EN 197-1, and is manufactured by Al2O3 13.482
“Bamburi Cement Ltd” in Kenya. The cement is safely kept in Fe 6.082
dry condition. Some important physical properties have been K2O 5.129
determined in the Laboratory, such as its Bulk density (loose CaO 1.090
and compacted) and its specific gravity as shown in Table I. Ti 0.545
Its chemical composition is as shown in Table II. Cl 0.333
Table I: Some Physical Properties of Bamburi Power Plus Mn 0.271
42.5 Zr 0.129
Specific Loose bulk density Compacted bulk Zn 0.048
gravity (Kg/m3) density (Kg/m3) Nb 0.027
3.197 1162.3 1398 Rb 0.019
Y 0.011
Table II: Chemical Composition of “Bamburi Power Plus Sr 0.002
42.5” Cu 0.002
Parameters Percentage (%) Table IV: Particle Size Distribution of Fines and Coarse
SiO2 20.61 Aggregates.
Al2O3 5.05
Sieve size
Fe2O3 3.24 Percentage passing
(mm)
CaO 63.37
Limits Limits
MgO 0.81 (Upper-Lower) (Upper-Lower)
SO3 2.75 as prescribed as prescribed
Sand Scoria
Na2O 0.15 by the standard by the standard
K2O 0.52 ASTM ASTM
Free CaO 0.63 C330-05 C330-05
Na Eq 0.49 25 - 100 100
Cl- <0.01 19 - 99.92 90-100
LOI 2.90
I.R. 1.00
C3A 7.91
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International Journal of Innovative Science and Modern Engineering (IJISME)
ISSN: 2319-6386, Volume-5 Issue-3, March 2018
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Properties of Lightweight Concrete made with Volcanic Scoria from Kenya, as Coarse Aggregates
Lightweight Coarse
Sand content Water cement Water content, Cement
Mix design Method aggregate content
(SSD) kg/m3 ratio (W/C) kg/m3 content, kg/m3
(SSD) kg/m3
Weight method 848.03 339.12 0.45 187 415.6
Absolute volume
516 764.64 0.45 187 415.6
method
Damp loose method 710.36 775.93 0.45 187 374.86
Table VII: 24 Hours Dry Density, Slump, Compressive and Splitting Tensile Strength at 7 days.
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International Journal of Innovative Science and Modern Engineering (IJISME)
ISSN: 2319-6386, Volume-5 Issue-3, March 2018
C. Air-Dry Density
Air dry density is one of the most important criteria for
concrete classification. According to ASTM C567 as well as
ACI 211.2-98 specifications, the air-dry unit weight of
concrete must not exceed 1842 kg/m3 to fit one of the
requirements for structural lightweight concrete. All the three
concrete specimen types fall within the required limits in
terms of air-dry density. The absolute volume method shows
the highest air dry density. Figure IV shows the different
values of air dry concrete density for each mix design
approach varying from 1820 to 1837 Kg/m3.
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Properties of Lightweight Concrete made with Volcanic Scoria from Kenya, as Coarse Aggregates
VI. RECOMMENDATIONS
Some recommendations can be made as regard to the
results obtained from the study.
Volcanic scoria aggregates can be used as an
alternative to artificial lightweight aggregates; therefore, they
should be industrially available in the form of aggregates like
the other aggregates types (normal weight aggregates and
artificial aggregates).
The absolute volume method of mix design is
highly recommended as the mix design approach for
structural lightweight aggregate concrete; mostly with natural
aggregates such as volcanic scoria as coarse aggregates.
Figure VII: Flexural strength for the three Mix Design
With regard to the high absorption rate of volcanic
Approaches at 7 and 28 days.
scoria aggregates, they can be pre-coated with a binding
material such as asphalt or plastic for instance, in a hot mix
V. CONCLUSIONS process, before the use in the concrete; further investigations
As regard to the results obtained from this investigation, some should be done in order to assess the physical and mechanical
conclusions can be drawn: properties of the lightweight concrete made with those
Volcanic scoria aggregates locally available in Kenya, pre-coated aggregates.
were found suitable as aggregates for the production of
structural lightweight aggregates concrete with regard to
ASTM C330 standard requirements.
Volcanic scoria aggregates met the grading
requirements in accordance with ASTM C330, for structural
lightweight concrete making.
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International Journal of Innovative Science and Modern Engineering (IJISME)
ISSN: 2319-6386, Volume-5 Issue-3, March 2018
ACKNOWLEDGMENT
We are sincerely grateful to both the African Union
Commission and Pan African University Institute for Basic
Sciences, Technology and Innovation (PAUSTI) for their
financial support for this research.
REFERENCES
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2. ACI 211.2-98, “Standard practice for selecting proportions for
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