Faculty of Engineering, Design and Technology

NAMES:
NIMWESIGA CHERIE M24B32/060
AHEISIBWE LISA-MARIA M24B32/037
JOAN MPANJA M24B32/047
OJUMAN PHILLIP M24B32/040
MUHOOZI JESSE M24B32/039
ASIIMWE JASPER M24B32/067
KIMURI DANIELLA M24B32/070
ASHERURA PAULINE M24B32/030
AINOMUGISHA TRIVIA M24B32/086

COURSE: Bachelor of Science in Civil and Environmental Engineering

YEAR: 1
SEMESTER: 2
LECTURER: MR. ZZIGWA MARVIN
DUE DATE: Wednesday 25th September 2024.
QUESTIONS:
Research on different types of rocks

PLAGIARISM DECLARATION:
I confirm that this assignment is my own work, is not copied from any other
person's work (published or unpublished), and has not previously submitted for
assessment either at Uganda Christian University or elsewhere. I confirm that I
have read and understood the Department and University regulations on
plagiarism.
GRANITE

Granite is a rock with a coarse-grained texture, rough and granular texture and
a light-colored igneous rock that is one of the most common types of rocks
found on Earth. It is composed mainly of quartz, feldspar, and minor amounts
of mica or amphiboles. Its composition gives it a speckled appearance, typically
in shades of white, pink, or gray, though its color can vary widely depending on
the specific minerals present. Granite is an intrusive igneous rock, meaning it
forms from the slow crystallization of magma beneath the Earth's surface.

Physical Properties of Granite

Chemical Composition: Primarily consists of quartz (SiO₂), feldspar (orthoclase
and plagioclase), and minor amounts of mica (biotite or muscovite) and
amphibole (hornblende).
It has a density of 2.6 to 2.75 g/cm³.
Cleavage: Poor to none, depends on the mineral content (quartz and feldspar
generally do not exhibit cleavage).
Crystal System: Igneous rock, so it doesn't exhibit one specific crystal system.
However, individual minerals within granite form in different crystal systems:
quartz (trigonal), feldspar (triclinic or monoclinic), etc.
Fracture: Irregular to conchoidal.
Luster: Vitreous (glassy) for quartz and feldspar, with a dull appearance in
weathered samples.
Mohs Hardness: 6 to 7, making it a durable rock suitable for various
applications.
Porosity: Generally low; granite is not porous.
Color: Ranges from light pink, gray, to white, often speckled with black due to
the presence of darker minerals like biotite.
Streak: White or colorless, typical of its major components (quartz and
feldspar).

Formation and Occurrence of Granite

Granite forms deep beneath the Earth's surface from the slow cooling of silica-
rich magma in the continental crust. As the magma cools, it crystallizes to form
large, visible mineral grains, giving granite its characteristic coarse texture.
Granite is a plutonic rock, which means it solidifies underground.
Over geological time, tectonic activity and erosion expose granite formations at
the surface.

Uses of Granite
1. Construction Material:
Granite has been used for centuries as a durable building stone. Its high
strength, resistance to weathering, and aesthetic appeal make it ideal for
constructing monuments, bridges, paving stones, and building facades.
Examples include iconic structures like the Egyptian pyramids and
Stonehenge, as well as modern buildings and memorials such as Mount
Rushmore in the USA.
2. Road Construction:
Crushed granite is used as an aggregate in asphalt and concrete for road
construction. Its strength makes it a suitable material for foundations
and roadbeds.
3. Monuments and Statues:
Granite has long been used in sculpture and monument construction
because it weathers well and retains its shape for centuries. Many
 gravestones and tombstones are made from granite because of its
resistance to erosion.
4. Crushed Stone:
Granite is crushed into smaller fragments and used for gravel in
construction projects, railroad ballast, and drainage systems.

Granite suitability analysis

This report examines the suitability requirements for granite in two specific
contexts: wastewater treatment and road construction material. These
material properties can be determined in a laboratory setting to evaluate the
potential uses of granite.
Suitability of granite for waste water treatment
In wastewater treatment, granite must possess certain properties to filter or
adsorb contaminants effectively. The relevant laboratorytested properties
include:
Porosity: Granite's low porosity makes it less suitable for filtration, though
crushed granite can still be used in filtration media for durability and resistance
to clogging.
Permeability: Granite’s low permeability limits its role as a direct filtration
medium but it may still be used in stabilizing filtration systems.
Adsorption Capacity: Granite can adsorb some contaminants, though it is not
as effective as more porous rocks. Laboratory tests assess its ability to adsorb
specific pollutants.
Chemical Resistance: Granite is highly resistant to chemical breakdown,
making it suitable in environments with diverse contaminants.
Mechanical Strength: Granite’s strength makes it suitable for use in
wastewater treatment structures that require durability under mechanical
stress.
Suitability of granite for road construction material
Granite is commonly used in road construction due to its strength and
durability. The following laboratorytested properties are critical for its use:
Compressive Strength: Granite’s high compressive strength makes it ideal for
road foundations that must support heavy loads.
Abrasion Resistance: Granite resists wear and tear, a crucial factor in areas
with heavy traffic. The Los Angeles (LA) abrasion test measures this property.
 Durability: Granite is resistant to weathering processes like freezing, thawing,
and moisture absorption, ensuring longevity in road layers.
Water Absorption: Granite’s low water absorption prevents weakening due to
moisture, especially in wet or freezethaw conditions.
Gradation and Particle Size Distribution: Crushed granite should be wellgraded
for compaction and stability. Laboratory sieving tests assess its particle size
distribution for road construction applications.
Summary of suitability requirements
For Wastewater Treatment: Porosity, permeability, adsorption capacity,
chemical resistance, mechanical strength.
For Road Construction Material: Compressive strength, abrasion resistance,
durability, water absorption, particle size distribution.

LIMESTONE (Lisa)

Limestone is a sedimentary rock composed

principally of calcium carbonate often in the form
of mineral calcite. It is composed of tiny fossils,
shell fragments and other fossilized debris usually
formed in marine areas but can also be formed
through chemical precipitation. Some limestone
varieties include dolomite (CaMg(CO3)2).
Properties; Colour: usually white to grey, though it can be beige or even darker
deending on the impurities.

 Fracture : splintery
 Porosity: it is Porous with variable absorption rates depending on its
grain size
 Luster :dull to pearly
 Cleavage: non existent
 Toughness: 1.0
 Specific gravity: 2.3- 2.7
 Transparency : opaque
 Density:2.3- 2.7g/cm3
 Mohs hardness rating :3-4
 Grain: fine grain size
It fizzes when exposed to Hydrochloric acid due to the formation of calcium
carbonate
 For wastewater treatment; because of its ability to neutralize acidity and
remove contaminants through adsorption. 1. Limestone's calcium
carbonate can increase the pH of acidic waters, making it suitable for
treating acidic wastewater. 2. For Filtration, the porous structure of
limestone can serve as a filtration medium, helping to remove impurities
from water. 3. Limestone has been shown to help in the removal of
metals like iron and manganese by facilitating precipitation.
 Suitability for Road Construction: As Road Base Material: Crushed
limestone is commonly used as a base material for road construction due
to its compaction ability and durability. Sub-base: It provides a stable
foundation for roads, contributing to load-bearing capacity Strength:
While limestone is softer compared to igneous rocks like basalt, its
compressive strength is generally sufficient for light to medium traffic
roads
Laboratory Properties to Test for Limestone:
1. Compressive Strength Test: To determine the ability of limestone
aggregates to withstand crushing forces.
2. Water Absorption Test: To measure the porosity and absorption levels,
which affect concrete performance
3. Specific Gravity Test: To determine its density, ensuring that it meets
required standards for concrete aggregates,
4. Chemical Composition Test: To ensure it doesn't contain harmful
impurities like magnesium oxide (which can cause durability
issues in concrete).
What Qualifies Limestone to be Processed into Aggregates for Concrete
Production?
 Workability: Limestone is relatively easy to crush into the desired size of
aggregates used in concrete production.
 Reaction with Cement: Limestone acts as an inert filler that reduces the
amount of cement needed in concrete, but it also reacts chemically with
cement to contribute to hydration, improving the workability and
durability of the mix.
 Strength: Although limestone isn’t as strong as granite or basalt, it still
provides adequate compressive strength for general construction
purposes.
  Availability: Its widespread availability makes it a cost-effective
aggregate option as it is found in places like Hima, Kasese District, and
Tororo.

BASALT

Basalt is a dark-colored, extrusive igneous rock that forms from the rapid
cooling of basaltic lava at the Earth's surface. It is one of the most common
rocks in the Earth's crust, known for its fine-grained texture and mineral
composition, which includes plagioclase, pyroxene, feldspar, and mica. Basalt’s
high durability and strength make it an essential material in construction and
engineering.
Mineral Composition
• Plagioclase: Provides light-colored crystals.
• Pyroxene: Dark mineral responsible for basalt's dark appearance.
• Feldspar and Mica: Minor components that contribute to the
overall texture and durability.
Physical Properties of Basalt
• Color: Dark grey to black due to high iron and magnesium content.
• Texture: Fine-grained; crystals are too small to be seen without
magnification.
• Density: 2.8–3.0 g/cm³ (higher than scoria due to its solid, non-
vesicular structure).
• Hardness: 6–7 on the Mohs scale, making it harder than many
other rocks.
• Compressive Strength: Ranges between 100–300 MPa, indicating
its ability to withstand heavy loads.
Applications of Basalt
1 Wastewater Treatment:
 Filtration Properties: Basalt’s porous nature makes it useful for
filtering contaminants in wastewater. I
ts high surface area promotes absorption, helping trap pollutants
effectively.
2 Road Construction:
High Compressive Strength: Basalt’s strength enables it to
withstand the heavy loads from vehicles without deforming, making it an
excellent material for road base and asphalt pavement.
Good Skid Resistance: Its rough surface texture increases traction
for tires, reducing skidding during wet conditions, thereby improving road
safety.
3 Concrete Aggregate:
Durability and Strength: Basalt’s high compressive strength and
resistance to weathering make it ideal for use as aggregate in concrete,
ensuring the concrete can bear heavy loads and last longer.
Workability: When properly graded, basalt enhances the
workability of concrete, making it easier to mix, place, and compact during
construction.
Summary
Basalt’s fine-grained texture, high strength, and durability qualify it as a
versatile material in construction and engineering, especially for wastewater
treatment, road building, and concrete applications. Its physical properties
make it highly resistant to weathering and suitable for use in heavy-load
environments.

QUARTZ
Quartz is one of the most famous minerals on earth. It is commonly found in
various types of rocks. The mineral composition of quartz is silicon dioxide
(SiO₂).
Quartz is found in:
 Igneous rocks like granite.
 Sedimentary rocks like sandstone, where quartz grains are typically
prominent.
 Metamorphic rocks like quartzite which is formed when sandstone rich
in quartz is subjected to high heat and pressure.
Category of Quartz
Quartz can be found in all three major rock categories:
 In Igneous Rocks, quartz appears in rocks such as granite.
 In sedimentary Rocks, it is common in sandstone where it forms due to
the erosion and deposition of silica.
 In metamorphic Rocks, quartzite is a metamorphosed form of sandstone,
made primarily of quartz.
Physical Properties of Quartz
Hardness: Quartz is quite hard, with a Mohs hardness of 7, which makes it
resistant to scratching.
Color: Quartz appears in various colors, including clear, white, pink (rose
quartz), and purple (amethyst).
Luster: Quartz has a vitreous (glassy) luster.
Fracture: Quartz has a conchoidal fracture, meaning it breaks into smooth,
curved surfaces.
Density: Its density is around 2.65 g/cm³.

Suitability Requirements of Quartz

1. Wastewater Treatment:
Quartz is often used in water filtration systems due to its hardness, chemical
resistance, and large surface area, which makes it effective in filtering out
particles.
2. Road Construction Material: Quartz is not used as the primary material
in road construction. But when it is crushed (into quartzite) it can be
used as an aggregate in road construction due to its hardness. Its
hardness (which is 7 on the mohs scale) contributes to the strength and
stability of the concrete.
Quartz is used in concrete, road construction materials and artificial marble.
 What Qualifies Quartz for Aggregates in Concrete Production.
Quartz can be processed into aggregates for concrete production due to:
High Hardness: This makes it durable and resistant to wear and tear when
crushed to make concrete.
Chemical Stability: Quartz doesn’t react with other substances in concrete
because it is chemically inert, ensuring long-lasting structural integrity of
concrete.
Abrasion Resistance: The hardness quality of quartz makes it resistant to
abrasion which is important for high-traffic areas.
Availability: Quartz is in abundance, which makes it cost-friendly hence easily
acquired as an aggregate material.

SANDSTONE

Sandstone is a sedimentary rock composed mainly of feldspar or quartz which

are renown as some of the most common minerals found in the earth’s crust.
This rock exists in a number of colours ranging from red, brown and yellow to
white and grey. Its colour is mainly determined by its mineral composition and
the environment in which the sandstone was formed.

Mineral Composition
Quartz:The most abundant mineral in sandstone.
Feldspar: A common component, often found alongside quartz.
Matrix: A finer-grained material that can include clays and other minerals
binding the sand grains together.
Physical Properties
Grain Size: Generally ranges from 0.0625 mm to 2 mm.
Porosity : Has a high porosity that allows for storage of water and oil.
Density: Typically ranges from 2.0 to 2.7 g/cm³.
Strength : It’s compressive strength varies widely but is often moderate.
Suitability of sandstone for waste water treatment
In wastewater treatment, the material used, in this case sandstone, should
possess particular properties to ensure it should effectively filter and absorb
impurities from water. Some of the most relevant properties include;
1. Porosity; This property determines the sandstone’s ability to allow water to
pass through it. High porosity is useful for filtration since it provides more
surface area for trapping particles.
2. Permeability; This measures how easily water flows through the rock.
Sandstone has sand sized particles with sufficient spacing between them that
enables it to easily filter waste water and prevent clogging.
3. Absorption capacity; Sandstone in reality has the capability to absorb
pollutants like hydrocarbons(crude oil and biodiesel) and heavy metals like lead
through capillary action and intermolecular forces. This ability enables it to
efficiently filter wastewater and labaratory tests enable us to assess the
property.
4. Chemical resistance; This refers to sandstone’s ability to withstand chemical
reactions and degradations when exposed to certain substances without
alteration to its physical aspects. There are numerous reasons as to why it
possesses this property ranging from its mineral composition to its cementing
materials and pH sensitivity.
Suitability for sandstone for road construction material
For the construction of roads, sandstone must possess certain physical and
mechanical properties to make sure that it can withstand the stresses of traffic
and weather. These properties include:
1. Compressive strength; This is a measure of how much sandstone can
withstand loads without crashing. This property in particular enables it to
withstand the weight of vehicles on roads and resist the wear and tear of
consistent use. Its high percentage of quartz and strong cementation materials
contribute a great deal to its strength.
2. Durability; Sandstone is able to resist weathering processes like freezing,
thawing and moisture absorption. Quartz is quite the strong mineral, so strong
that it’s able to withstand physical and chemical stress that would cause it to
break down. Other minerals in the rock like silica and iron oxide act as
cementation materials and also enhance the rock’s ability to withstand
weathering
3. Gradation and particle size distribution; In the construction of roads, the
size of sandstone particles is vital. Properly graded materials provide better
compaction and strength.
Several factors qualify sandstone to be processed into aggregates for concrete
production:
1.Compressive Strength: Sandstone generally possesses good compressive
strength, which is essential for concrete applications. Strong aggregates
contribute to the overall strength and durability of the concrete mix.

2. Particle Size and Shape: Sandstone can be crushed and processed to

produce aggregates with a var’st number of particle sizes, ranging from coarse
to fine. Well-graded aggregates enhance the workability of concrete.

3. Durability: The durability of sandstone against weathering and mechanical

wear makes it suitable for use in concrete. Durable aggregates help improve
the lifespan of concrete structures therefore reducing maintenance and repair
costs.

4. Low Absorption: Sandstone has a moderate absorption capacity.

Aggregates with low absorption rates are used more often since they minimize
the potential for water-related damage and ensure consistent concrete
performance.

5. Chemical Composition: The mineral composition of sandstone, which mainly

includes quartz, provides chemical stability in concrete. Quartz being inert
contributes to the overall quality and prevents adverse chemical reactions that
could weaken the concrete.
PUMICE

Pumice is a light weight porous volcanic rock formed during volcanic eruptions.
It is created when lava with a high gas and water content cols rapidly causing
the gas to escape rapidly. Due to its lightness, it can sometimes float on water.
Pumice is widely recognized for its abrasive properties.

Physical Properties
Chemical composition: silica (SiO₂), along with aluminum oxide (Al₂O₃), iron
oxide (Fe₂O₃), magnesium oxide (MgO), and calcium oxide (CaO)
Density: Extremely low
Crytal System: non-crystalline because pumice is a type of volcanic glass.
Luster: Dull
Mohs Hardness: 6
Fracture: Irregular
Cleavage: None
Color: light gray, brown depending on mineral content
Streak: White

Pumice in Water filtration

Pumice’s porous structure makes it ideal for the use in water filtration systems
by pumice filtration. it helps remove sediments and organic materials from
water thus making it a valuable resource for waste water treatment.
To expound even more
Pumice due to its large surface area allows water to flow through it easily while
capturing suspended particles, and other organic particles.
Pumice in its self doesn’t react with water or water impurities which is crucial
of maintain the integrity of water treatment system overtime without loss of
effectiveness.

Pumice in Construction
Finely ground pumice can be used as a pozzolan (can react with lime to form
cement) which helps improve strength and durability of concrete which can be
seen in the ancient Roman buildings that used pumice in cement and are still
standing until today.
Pumice is used in the construction industry as a light weight aggregate in
concrete. Due to its porous nature, it adds insulating and lightweight properties
to the final product while still maintain sufficient strength.
Pumice is resistant to weathering and chemical degradation which makes it a
suitable rock to be used for roads in regions that experience harsh weather
conditions as it wont break down or deteriorate as easily as other materials.

Did you know

Due to its low density and gas bubbles, pumice can float on water.

SCORIA

Scoria is a dark-colored, volcanic rock with a highly vesicular texture. It forms

when magma, rich in gases, rapidly cools and depressurizes during volcanic
eruptions. Scoria is composed primarily of amorphous aluminum silicate, with
varying amounts of iron and magnesium oxides. Its numerous vesicles make it
lightweight and porous, making it useful in various engineering applications.

Physical Properties of Scoria

Chemical Name: Amorphous Aluminum Silicate (with iron, magnesium, and
other volcanic minerals)
Density: 0.8–1.2 g/cm³
Cleavage: Absent
Color: Usually black, reddish-brown, or dark grey
Specific Gravity: 0.8–1.2
Streak: White or light grey
pH: Around 7–7.5
Radioactivity: None
Mohs Hardness: 5–6

Applications of Scoria
1. Wastewater Treatment: Scoria's porosity makes it an effective filter medium
for wastewater treatment.
2. Lightweight Aggregate: Scoria is used as a lightweight aggregate in concrete,
reducing structural load.
3. Landscaping: Scoria is commonly used in landscaping and for garden beds,
helping retain moisture and prevent soil erosion.
4. Drainage Material: Its porosity makes it suitable for drainage in construction.
5. Road Construction: Scoria is used as a base material for roads and driveways
due to its stability and drainage capacity.
SLATE
Slate is a fine-grained foliated metamorphic rock
that is derived from an original shale-type
sedimentary rock through low-grade regional
metamorphism. It is known for its ability to break
into thin, flat sheets, which is called slaty cleavage.
It is primarily composed of fine-grained minerals
such quartz, mica, chlorite and illite. These
minerals, along with the rock’s foliated structure (parallel alignment of
minerals), give slate its characteristic ability to split into thin, flat sheets.

The formation of slate involves a process of low-grade metamorphism of

sedimentary rocks, particularly shale, under relatively low temperature and
pressure conditions. This transformation alters the mineral composition and
structure of the original rock over time, resulting in the characteristic features
of slate.

The main characteristics of slate are; foliation where it has a characteristic of

layering due to the parallel alignment of platy minerals like mica. Its varying
colours, including shades of grey, green, purple, red, and black depending on its
mineral content. It is also characterised with durability as it is relatively hard
and resistant to weathering, which makes it suitable for long-term use in
construction.
Slate, being durable and a fine-grained metamorphic rock, has several
properties that make it valuable for various applications, including waste water
treatment and road construction. The following are the key properties of slate
that can be assessed in the laboratory for these uses:
 Waste water treatment; slate can be used in waste water treatment as a
filtration medium or absorbent material. The properties that can be
determined in the laboratory include porosity and permeability which is
to determine or evaluate how well water can pass through the slate
material, surface area which is measured since a higher surface area
value allows for better absorption of contaminants like heavy metals and
organic compounds. Another property determined is absorption
capacity which gives it the ability to absorb pollutants which makes it
useful in the removal of impurities from wastewater.
  Road construction material; slate is used as a base material or aggregate
in asphalt and concrete mixtures. The key properties evaluated in the
lab for this application include:
- Compressive strength which is essential for the slate to withstand the weight
and pressure of traffic loads.
-Los Angeles (LA) Abrasion test which assesses the durability and ability of slate
to resist degradation due to abrasion and impacts.
-Aggregate Impact Value (AIV) which ensures that the slate can resist sudden
shocks or loads, an important property for road aggregates.
-Water absorption which when low is desirable to prevent deterioration due to
freeze-thaw cycles in road construction
-Frost resistance which is to ensure that slate can withstand freeze-thaw cycles
without significant degradation, especially in regions with cold climates.
-Specific gravity which is determined such that when it is high often indicates a
denser and stronger material, which is important for road base and asphalt
mixtures.
Slate is also used as aggregates for concrete production. This is because of its
several key qualities which qualify it to and these are;
 Chemical stability: slate is chemically stable which means it won’t react
with cement or other components of the concrete mix. This ensures
long-term durability of the concrete.
 Resistance to weathering: slate’s mineral composition makes it resistant
to weathering, making it a good aggregate for outdoor concrete
applications where exposure to the elements is a concern.
 Particle shape and texture: when crushed, slate produces angular and
rough textured particles. These characteristics improve the bonding of
the aggregate with the cement matrix, resulting into stronger concrete.
 Hardness and durability: slate has a high hardness and is durable, which
means it can withstand wear and tear in concrete providing structural
strength.
 Low water absorption: slate generally has a low porosity and low water
absorption which makes it resistant to freeze-thaw cycles. This is crucial
for concrete in environments that experience temperature fluctuations.
 Availability and cost: slate may be abundant in some areas making it an
economical choice for use as aggregate in concrete.
QUARTZITE

Quartzite is a natural stone formed from sandstone that has undergone heat
and pressure over time, turning it into a hard, durable material. It consists
mostly of quartz, a mineral known for its toughness and resistance to
weathering.

The mineral composition

Most quartzite rocks contain at least 90% quartz minerals, but some are nearly
pure silica with quartz mineral concentrations as high as 99 percent. The
chemical composition of quartzite is dominated by SiO2 (silicon dioxide) but
may also include trace amounts of other oxides and silicates.

The Category of the Rock

Quartzite is a metamorphic rock formed when sandstone is exposed to heat
and pressure

Physical Properties of Quartzite

Hardness: Quartzite is a very hard rock, rating 7 on the Mohs hardness scale.
This high hardness is due to the quartz content, which also makes quartzite
resistant to abrasion.
Density: Quartzite has a high density, generally ranging from 2.6 to 2.8 per
cubic centimeter.
Porosity: Quartzite is non-porous meaning it absorbs very little water which
makes it ideal for outdoor use.
Durability: It is extremely durable due to its quartz composition and tight grain
interlocking structure.

Color: Quartzite is typically white or light grey in color. Other impurities can
cause it to be yellow, orange, brown, green or blue.
Foliation: It does not display significant foliation, which is the layering caused
by mineral alignment under pressure.
Fracture: it has an uneven fracture breaking along curved surfaces
Grain size: Quartzite is medium in size.
Luster: Quartzite has a glassy shiny appearance due to its high quartz content.

Suitability Requirements Of quartzite

Wastewater Treatment

Quartzite, being non-porous and chemically inert, does not easily react with
acids or water, making it nearly impermeable. Its low water absorption makes it
unsuitable for direct filtration in wastewater treatment. However, due to its
durability and resistance to weathering, quartzite is well-suited for constructing
infrastructure around water treatment plants. Its resistance to chemical
corrosion ensures it remains intact in wet environments, making it an excellent
material for such construction projects.
Road Construction Material
Quartzite is an excellent choice for road construction as it can be crushed into
aggregates used as a base for roads and railways. Its hardness and wear
resistance make it ideal for handling the constant stress from vehicles.
Additionally, quartzite’s durability and resistance to weathering and erosion
extend the lifespan of roads built with it. Its toughness also ensures roads
maintain quality over time by resisting wear and abrasion.

What qualifies quartzite to be processed into Aggregates for Concrete

Production?
Hardness: Quartzite is very hard, which makes concrete strong and able to
handle heavy loads and stress.
Durability: It is long-lasting and doesn’t break down easily in harsh weather or
from chemicals, making it ideal for concrete used outdoors.
Low Porosity: Quartzite doesn’t absorb much water, so it helps prevent cracks
caused by freezing and thawing in concrete.
Resistance to Wear: Because it’s so hard, quartzite resists being worn down,
which helps keep concrete surfaces in good condition, even in areas with lots
of traffic.
Chemical Stability: Quartzite doesn’t react with other materials or chemicals,
which keeps the concrete strong over time.
Good Bonding: Quartzite works well with cement, ensuring the concrete stays
solid and performs well in construction.
How to use the Mohs scale
The Mohs scale of mineral hardness is a qualitative ordinal scale used to
characterize the scratch resistance of minerals based on their ability to scratch
or be scratched by other materials. Here’s how it works:
Scale Range: The Mohs scale ranges from 1 to 10, with 1 being the softest and
10 being the hardest.
Scratch Test: To determine a mineral’s hardness, you compare it against
reference minerals. If a mineral can scratch another mineral, it has a higher
hardness value.
Reference Minerals: Each hardness value corresponds to a specific reference
mineral. For example:
Talc (hardness 1) is the softest.
Diamond (hardness 10) is the hardest.
Field Identification: Geologists use the Mohs scale in the field to roughly
identify minerals using scratch kits.
Not Industrial Durability: While useful for mineral identification, the Mohs
scale doesn’t predict how well materials endure in an industrial setting.
Remember, it’s a fun and practical way to understand mineral hardness, but
not a precise measurement!

Aggregate crushing value (acv)

• The Aggregate Crushing Value (ACV) test is a crucial assessment
performed on coarse aggregates used in road construction. Let’s delve
into the details:
1. Purpose: The ACV test determines the resistance of aggregates to
crushing under gradually applied compressive load.

Procedure:
1. A cylindrical specimen of size 25 mm in diameter and 25 mm in
height is prepared from the parent rock.
2. The specimen is subjected to a compressive stress.
3. The test is generally conducted on aggregate passing through
a 12.5 mm sieve and retained on a 10 mm sieve.
 4. A load of 40 tons is applied through a plunger in a compression
testing machine.
5. The crushed aggregate sample finer than 2.36 mm is separated
and expressed as a percentage of the original weight taken in the
mold.
2. Calculation:
1. The percentage of weight passed through the 2.36 mm IS sieve is
known as the Aggregate Crushing Value.
2. If the aggregate value is 30 or higher, it may be a mistake, and in
such cases, the “ten percent fines value” should be determined
and used instead.
• In summary, the ACV test helps assess the strength of aggregates and
their suitability for concrete applications. Remember, this method
provides a practical understanding of aggregate behavior, but it’s not a
precise measurement!

Aggregate impact value

• The Aggregate Impact Value (AIV) test evaluates the toughness of
coarse aggregates used in construction. Let’s explore this test further:
1. Purpose:
1. The AIV test assesses the resistance of aggregates to sudden
impact or shock loads.
2. It helps determine whether aggregates can withstand the impact
they might experience during their service life, such as when
vehicles pass over speed breakers or travel on undulating roads.
3. If the result is satisfactory, the aggregates are suitable for use in
pavements; otherwise, they are rejected.
2. Test Procedure:
1. A cylindrical specimen (25 mm diameter and 25 mm height) is
prepared from the parent rock.
2. The specimen is subjected to a compressive stress using an impact
testing machine.
3. A steel cup-shaped cylinder (internal dimensions: diameter = 102
mm, depth = 50 mm, thickness = 6.3 mm) holds the specimen.
 4. A hammer with cylindrical ends (13.5 to 14 kg, diameter = 100
mm, length = 50 mm, chamfer at lower edge = 2 mm) delivers the
impact load.
5. Sieves with the following sizes are used: 12.5 mm, 10 mm, and
2.36 mm.
6. The aggregate passing through the 2.36 mm sieve is weighed
(W2).
3. Calculation:
1. The Aggregate Impact Value is calculated as: AIV =(W 1/W 2 ​​)× 100
where:
1. (W1) = Weight of the fraction passing through a 2.36 mm IS
sieve (typically 220 g).
2. (W2) = Weight of the fraction retained on the 2.36 mm
sieve.
4. Interpretation:
1. A higher AIV indicates greater toughness and better resistance to
impact.
2. Lower AIV values are desirable for aggregates used in pavements.
• Remember, the AIV test provides practical insights into aggregate
behavior, but it’s not a precise measurement!
• For more details, refer to the IS Code 2386 (Part 4) – 19631.

Other methods of testing suitability of a rock

1. Petrographic Tests:
1. Purpose: To examine the rock’s suitability at a microscopic level.
2. Procedure:
1. Suitable surfaces (polished or thin sections) are prepared.
2. The samples are examined using a petrological microscope
with reflected or transmitted light.
3. Petrographic tests provide insights into the rock’s mineral
composition and potential reactivity with cement in concrete.
2. Water Absorption Test:
1. Purpose: Determines the rock’s ability to absorb water.
2. Procedure:
1. The rock is immersed in water for a specified duration.
2. The percentage of water absorbed is calculated.
 3. Acceptance Criteria: Good building stones should absorb less than
5% water.
• Remember, these tests provide practical insights into the rock’s behavior,
but they are not precise measurements. Consulting geologists and
engineers is essential for accurate assessments