Chapter 1 INTRODUCTION 1.1 BACKGROUND OF STUDY Concrete, as a basic necessity for project constructions in the Bicol Region, raised ideas about altering its compositions and mixtures that involved new kinds of aggregates may it be fine or coarse. As part of every concrete, mortar always played a major role. If one considers its uses like for plastering, tiles and hollow blocks grouting, and its role in the concrete cement as a binder of coarse aggregates, truly it should be highly regarded. Mortar as part of concrete cement has a direct effect to the concrete’s service load capacity. Good mortar in concrete obviously improves concrete allowing it to carry higher service loads. Mortar, also used as plaster and grout, on the other hand has direct effect on slabs and beams due to its own weight which increases the service load carried by the structural members, 1
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Chapter 1
INTRODUCTION
1.1 BACKGROUND OF STUDY
Concrete, as a basic necessity for project constructions in the Bicol Region, raised ideas
about altering its compositions and mixtures that involved new kinds of aggregates may it be fine
or coarse. As part of every concrete, mortar always played a major role. If one considers its uses
like for plastering, tiles and hollow blocks grouting, and its role in the concrete cement as a
binder of coarse aggregates, truly it should be highly regarded.
Mortar as part of concrete cement has a direct effect to the concrete’s service load
capacity. Good mortar in concrete obviously improves concrete allowing it to carry higher
service loads. Mortar, also used as plaster and grout, on the other hand has direct effect on slabs
and beams due to its own weight which increases the service load carried by the structural
members, thus causing a new field for research regarding mortars with lesser weight.
There are so many innovations in making the concrete lighter in order to reduce the loads
which would result to the decrease on the dimensions of the beams, columns, footings, and other
load bearing members. Lightweight concrete could be manufactured using lightweight
aggregates both fine and coarse or normal aggregates and lightweight fine aggregates.
For past studies in the Philippines regarding lightweight concrete, researchers worked
very hard to attain the required compressive strength of 17 MPa or 2500 psi for residential
buildings using both fine and coarse lightweight aggregates, but they did not succeed. These
researchers found out that there were so many factors to be considered. The specific gravity of an
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aggregate plays a big role in the computation of the design mix. Since, the lightweight floats on
water, for now, the past researchers had not found a way to determine the specific gravity of the
aggregates due to the lack of equipment in their locations.
In order to simplify the research due to its complications, the researchers decided to focus
on determining the compressive strength of mortar itself using lightweight fine aggregates. The
proponents used pumice as their lightweight aggregate since it is locally available and abundant.
Bicol Region as part of a tropical country, the Republic of the Philippines, is rich in
natural resources. These resources include coarse and fine aggregates that can be used in
construction. In addition to this, pumice, a lightweight rock, is available in Casiguran, Sorsogon.
In this comparative study between ordinary and lightweight fine aggregates used in mortar
cement, the researchers used this pumice, which were crushed to make fine aggregates.
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1.2 STATEMENT OF THE PROBLEM
This study aims to evaluate the differences and similarities of ordinary sand mortar
cement and pulverized pumice mortar cement.
1. Which among the two mixes posses higher strength capacity?
2. How much lighter is the pulverized pumice mortar cement compared to the ordinary
mortar cement?
3. What effect do lightweight aggregates when combined with ordinary cement have to
the mortar cement?
4. What would be the factors that could affect the compressive strength of the
lightweight mortar?
1.3 SIGNIFICANCE OF STUDY
This study shall benefit the following:
To Teachers, Students and Civil Engineers, this research will generate other innovative
ideas for the use of lightweight in construction specially mortar.
To End Users, this will benefit them through economical purposes since lightweight
mortar cement reduces the dead load carried by structural members, which then allows structural
designers to reduce the sizes of load bearing members.
To Future Researchers, this research will serve as their reference and basis for their own
study.
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1.4 GENERAL OBJECTIVE
The main objective of this study was to evaluate and compare the strength and weight of
the mortar using ordinary sand and pulverized lightweight rocks. Furthermore, it also
endeavoured to determine the effect of introducing crushed pumice to sand mortar, which means
the combination of lightweight fine aggregate and ordinary sand.
1.5 SPECIFIC OBJECTIVE
The specific objective of this study was to closely compare the strength and weight
difference between the lightweight-mixed mortar, ordinary-mixed mortar, and combined-mixed
mortar, thus allowing the research to show results that can be used in further studies and actual
constructions.
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1.6 ASSUMPTION
This comparative research analysis assumed that lightweight mortar mixes were
significantly lighter than ordinary mortar mixes. Thus, their strength capacities were relatively at
par and either can be used for construction.
1.7 SCOPE AND LIMITATION
Scope
This comparative research analysis was intended to qualitatively compare ordinary
mortar mixes and lightweight mortar mixes. In this research, the mortar mixes’ strength and
weight were closely evaluated. In turn, this research may be used as a basis for consideration of
lightweight mortar mixes in actual constructions.
Limitations
This research was limited only to the attainment of the highest possible strength of mortar
cement mix using crushed pumice, Portland cement and Albay sand.
The researchers did not use any mixing equipment due to the unavailability of such; thus,
what the proponents did was to mix the mortar manually, so there might be irregularities in some
aspect of the design mix such as the water-cement ratio that also affects the workability of the
mix aside from its compressive strength.
The researchers used 1:1 ratio, 1:2 ratio, 1:3 ratio and 1:4 ratio in designing the mix
which is basically not present in any existing codes. This cement-fine aggregate ratio was based
on the observations and findings on the actual field conditions or construction sites.
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1.8 DEFINITION OF TERMS
The following terms were defined according to its context in engineering:
Absorption. This refers to the ability of a material to hold water within itself
Cement Mortar . This is an intimate mixture of cement and sand mixed with sufficient water to
produce a plastic mass. The amount of water varies according to the proportion and condition of
the sand, and had best be determined independently in each case. Sand is used both for the sake
of economy and to avoid cracks due to shrinkage of cement in setting.
Cementitious. This relates to a chemical precipitate, especially of carbonates, having the
characteristics of cement.
Compressive strength. It is the capacity of a material to withstand axially directed pushing
forces.
Curing. It pertains to a procedure for insuring the hydration of the Portland cement in newly-
placed concrete. It generally implies control of moisture loss and sometimes of temperature.
Dead load. This refers to the intrinsic invariable weight of a structure, such as a bridge. It may
also include any permanent loads attached to the structure also called dead weight.
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Pumice . This is also called pumice stone, a light porous acid volcanic rock having the
composition of rhyolite, used for scouring and, in powdered form, as an abrasive and polish.
Pumice Cement Mortar. This is a mixture of crushed pumice as sand substitute and cement
mixed with sufficient amount of water.
Sieve Analysis (or gradation test). This is a practice or procedure used to assess the particle
size distribution (also called gradation) of a granular material.
Specific Gravity. This refers to the ratio of cement’s density to the density of some standard
material, such as water at a specified temperature, for example, 60°F (15°C), or (for gases) air at
standard conditions of temperature and pressure. Specific gravity is a convenient concept
because it is usually easier to measure than density, and its value is the same in all systems of
units.
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Chapter 2
REVIEW OF RELATED LITERATURE AND STUDIES
A. RELATED LITERATURE
The use of pumice has been known to the world centuries ago. One application of pumice
was during the ancient Rome. Pumice was used to build thermal baths and temples, like
Pantheon of Rome. Vitruvio’s compendium of architecture, dated from 1st B.C., is one of the
earliest references regarding the special properties of pumice. Vitruvio describes that pumice is
lighter than water.
Other special properties of pumice are thermal insulation, sound insulation, and
resistance to freezing, resistance to fire, water absorbency and apparent density. Pumice has
reduced thermal conductivity than that of normal concrete. Also, pumice is a good sound
insulator due to its high absorbency of sound. Pumice, also, has higher water absorbency than
that of ordinary aggregates used in construction.
Resistance to freezing is one of the special properties of pumice. An experiment was
conducted to prove that pumice samples are resistant to intense cold. Samples submerged in
water for 48 hours, placed in a freezer at 100C for 9 hours and immersed again in water at 350C
for 15 hours (and submitted to this cycle 20 times) showed no visible signs of damage,
deterioration or breakdown. Also pumice is resistant to fire. When a 60 mm thick wall is exposed
to flame with temperature of 12000C, the temperature of the opposite side will not exceed
1250C. Many chimneys could be made of pumice concrete or blocks. (APEX GULF, 2003)
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Building with Pumice
Pumice is a very porous form of vitrified volcanic rock, usually of very light colon.
Pumice floats on water. In other words, pumice is very light. It has roughly the consistency of a
mixture of gravel and sand, with light, porous individual granules that normally either float on