Architecture first semester -Building materials

1. BUILDING MATERIALS - I

2. UNIT – I
soils
 Fundamentals of Soil Science
 Types of soils
 Principles of Soil Stabilization
 Characteristics of core
 Types of Stabilizers
 Requirements and Types of mudwall building and
 Surface protection.

3. NEED TO STUDY ABOUT SOIL
Why to Study about Soil?
 The living skin of the earth sustaining life (6.4 billion
people and rising)
 World population is increasing rapidly but only 10% of
the world’s land area is suitable for growing crops
 Soil quality is degrading world-wide
 Good soil management enhances the quality of soil,
water, and air.

4. SOIL - DEFINITION
 Soil is a thin layer of material on the Earth's
surface in which plants have their roots. It is made
up of many things, such as weathered rock and
decayed plant and animal matter. Soil is formed
over a long period of time.
 Soil is the unconsolidated mineral or organic
material on the immediate surface of the Earth that
serves as a natural medium for the growth of land
plants.

5. SOIL - DEFINITION
 Soil is a natural body comprised of solids (minerals
and organic matter), liquid and gases that occurs on
the land surface, occupies space, and is
characterized by one or both of the following:
horizons, or layers, that are distinguishable from the
initial material as a result of additions, losses,
transfers, and transformations of energy and matter
or the ability to support rooted plants in a natural
environment.

6. SOIL - DEFINITION
The unconsolidated mineral or organic matter on
the surface of the Earth that has been subjected to
and shows effects of genetic and environmental
factors of: climate (including water and
temperature effects), and macro- and
microorganisms, conditioned by relief, acting on
parent material over a period of time. A product-
soil differs from the material from which it is
derived in many physical, chemical, biological,
and morphological properties and characteristics.

7. introduction
• The development of a soil is influenced by
five interrelated factors:
– Organisms
– Topography
– Time
– Parent material and
– Climate
• Living organisms have a role in a number of
processes involved including organic matter
accumulation, profile mixing and
biogeochemical nutrient cycling.
• Through the process of decomposition, organisms and nutrients to the soil which
influences soil structure and fertility.
• Surface vegetation also protects the upper layers of a soil from erosion by way of
binding the soils surface and reducing the speed of moving wind and water across
the ground surface.

8. introduction
• Soil is the unconsolidated mineral matter that has been subjected to and
influence by genetic and environmental factors:
– Parent material
– Climate
– Organisms and topography all acting over a period of time
• It is made up of weathered rock fragments and decaying remains of plants and
animals (organic matter).
• It also contains varying amounts of water and microorganisms. It furnishes
mechanical support and nutrients for growing plants.
• Soil as a natural body consisting of layers(soil horizons) of mineral constituents
of variable thickness, which differ from the parent materials in their
morphological, physical, chemical and mineralogical characteristics.

9. introduction
• Parent material refers to the rock and mineral materials from which the soils
develop.
• These materials can be derived from residual sediment due to the weathering of
bedrock or from sediment transported into an area by way of the erosive forces
of wind, water or ice.
• Topography generally modifies the development of soil on a local or regional
scale.
• Climate plays a very important role in the genesis of a soil.
• The two most important climatic variables influencing soil formation are
temperature and moisture.
• Temperature has a direct influence on the weathering of bedrock to produce
mineral particles.
• Time influences the temporal consequences of all of the factors.

10. introduction
• All the rocks, when subjected to the forces of the nature like weathering
agencies of wind, water, temperature, frost, waves etc., are weakened
considerably and subsequently the rocks are disintegrated into soils by the
process of mechanical disintegration, chemical decomposition and solution.
• From engineering standpoint, the soil is a natural aggregate of mineral grains
formed by the disintegration or decomposition of the rocks.
• The engineering properties and behavior of soils are generally influenced by
the changes in the moisture content and density of compactness of the soil.
• Most soils contain four
basic components:
Mineral particles, water, air
and organic matter.
• Organic matter can be
further sub-divided into
humus, roots and living
organisms.
SOIL COMPOSITION

11. SOIL PROFILE
• The O horizon is the topmost layer of most soils.
• It is composed mainly of plant litter at various levels of decomposition and humus.
• A horizon is found below the O layer
• This layer is composed primarily of mineral particles and has two characteristics:
A) it’s the layer in which humus and other organic materials are mixed with mineral
particles and
• B) it’s a zone of translocation from which eluviation has removed finer particles and
soluble substances, both of which may be deposited at a lower layer.
• Eluviations refers to the movement of fine mineral particles(like clay) or dissolved
substances out of an upper layer in a soil profile.
• The deposition of fine mineral particles or dissolved substances in a lower soil layer
is called illuviation.

12. SOIL PROFILE
• Most soils have a distinct profile or sequence of horizontal layers.
Generally, these horizons result from the processes of chemical
weathering, eluviation, illuviation and organic decomposition.
• Typical soil contains five different layers in its profile : O, A,B,C and R
horizons.

13. SOIL PROFILE
• The B horizon is a mineral soil layer which is strongly influenced by
illuviation.
• Consequently, this layer receives material eluviated from the A horizon.
• The B horizon also has a higher bulk density than the A horizon due to its
enrichment of clay particles.
• The C horizon is composed of weathered parent material.
• The texture of this material can be quite variable with particles ranging in
size from clay to boulders.
• The final layer in a typical soil profile is called the R horizon. This soil
layer simply consist of unweathered bedrock.

15. Physical properties
 The physical properties of a soil are the result of soil parent materials being acted
upon by climatic factors (such as rainfall and temperature), and affected by
topography (aspect) and life forms (kind and amount such as forest, grass or soil
animals) over a period of time.
 A change in result of these influences usually results in a difference in the type of
soil formed.
 Important physical properties of a soil are
- Color
- Texture
- Structure
- Drainage
- Depth and
- Surface features (stoniness, slope and erosion)

16. Physical properties
 Color
• When soil is examined, color is one of the first things noticed.
• In general, color is determined by: (1) organic matter content, (2) drainage
conditions (3) degree of oxidation (extent of weathering).
• Surface soil colors vary through shades of brown and grey to black.
• Light colors indicate a low organic matter content and dark colors can indicate a
high organic content. Light or pale colors in the surface soil are frequently
associated with relatively coarse texture, highly leached conditions and high annual
temperatures.
• Dark colors may result from high water table conditions (poor drainage), low annual
temperatures, or other conditions that induce high organic matter content and at the
same time, slow the oxidation of organic materials.
• However, soil coloration may be due to the color imparted by the parent material.

17. Physical properties
 Texture
• Texture refers to the relative amounts of differently sized soil particles, or
the fineness/coarseness of the mineral particles in the soil.
• Soil texture depends on the relative amounts of sand, silt and clay.
• In each texture class, there is a range in the amount of sand, silt and clay that
class contains. Ex.: The mineral constituents of a loam soil might be 40%
sand, 40% silt and the balance 20% clay by weight.
• Clay is probably the most important type of mineral particle found in a soil.
• Clay particles are also somewhat flexible and plastic.
• This feature allows clay particles to absorb water and other substances into
their structure.

18. Physical properties
• The amount or percentage of
each element determines the
soil texture.
 Example of silty clay loam
to determine its percentage
of sand, clay and silt.
- 15% sand
- 60% silt
- 25% clay

19. Physical properties
 Structure
• In the majority of soils the particles do not exist as individual grains but are packed
together in clumps or peds.
• The individual peds can be distinguished as a variety of shapes.
• Crumbs are small and spherical, larger peds are more angular and these can be
blocky or if elongated are said to be prismatic and final platy or flat.
• The soil structure is a result of both the texture and processes that have formed the
soil such as root action.
• The structure has an effect on the stability of soil, more angular peds having higher
stability that soils made up of small crumbs.
• The structure of the soil also has an effect on the amount of air and water in the soil.
• Crumb soils contain large portions of sand and platy soils are high in clay.

20. Physical properties - structure

21. Physical properties
 Drainage:
• Soil drainage is defined as the rate and extent of water movement in
the soil, including movement across the surface as well as downward
through the soil.
• Slope is a very important factor in the soil drainage.
• Soil drainage is indicated by soil color.
• Clear bright color indicate well-drained soils.
• Too much or too little water in the soil is equally undesirable.
• The most desirable soil moisture situation is one in which
approximately one-half of the pore space of the soil is occupied by
water.

22. Types of soils

23. Types of soils
• Depending on the size of the particles in the soil, it can be classified into
following types:
– Sandy soil
– Silty soil
– Clay soil
– Loamy soil
– Peaty soil
– Chalky soil
 Sandy soil – This type has the biggest particles and the size of the
particles does determine the degree of aeration and drainage that the soil
allows.
• It is granular and consists of rock and mineral particles that are very
small.
• Therefore the texture is gritty and sandy soil is formed by the
disintegration and weathering of rocks such as limestone, granite, quartz
and shale.

24. Types of soils
 Silty soil – silty soil is considered to be one of the most fertile of soils
• It can occur in nature as soil or as suspended sediment in water
column of a water body on the surface of the earth.
• It is composed of minerals like quartz and fine organic particles.
• It is granular like sandy soil in case silty soil is dry it has a smoother texture
and looks like dark sand.
• This type of soil can hold more moisture and at times becomes compact. It
offers better drainage
SILTY SOIL

25. Types of soils
 Clay soil – Clay is a kind of material that occurs naturally and consists of
very fine grained material with very less air spaces, that is the reason it is
difficult to work with since the drainage in this soil is low.
• Clay soil becomes very heavy when wet.
• Clay soil is formed after years of rock disintegration and weathering.
• It is also formed as sedimentary deposits after the rock is weathered, eroded
and transported.
CLAY SOIL

26. Types of soils
 Loamy soil- This soil consist of sand, silt and clay to some extent.
• It is considered to be the perfect soil.
• The texture is gritty and retains water very easily, yet the drainage is well.
• There are various kinds of loamy soil ranging from fertile to very muddy
and thick sod.
LOAMY SOIL

27. Types of soils
 Peaty soil- this kind of soil is basically formed by the accumulation
of dead and decayed organic matter, it naturally contains much more
organic matter than most of the soils.
• It is generally found in marshy areas. This kind of soil is formed in
wet climate.
PEATY SOIL

28. Types of soils
 Chalky soil- Unlike peaty soil, chalky soil is very alkaline in nature and
consist of a number of stones.
• This kind of soil depends on the depth of the soil that is on the bed of
chalk.
• This kind of soil is prone to dryness in summers.
• Chalky soil, apart from being dry also blocks the nutritional elements for
the plants like iron and magnesium.
CHALKY SOIL

29. types of Soil
The main types of soil in India are as follows:
1) Red soils
2) Laterites and lateritic soil
3) Black soil
4) Alluvial soils
5) Forest & hill soils
6) Peaty and marshy soils

30. Soil stabilization
 Soil stabilization is the improvement of stability or bearing
power of the soil by the use of controlled compaction,
proportioning and/or the addition of suitable admixtures or
stabilizers.
 There are three purposes of soil stabilization that includes:-
Strength improvement – to increase the strength of the
existing soil to enhance its load-bearing capacity.
Dust control – to eliminate or alleviate dust generated by the
operation of equipment during dry weather.
Soil waterproofing – to preserve the natural or constructed
strength of a soil by preventing the entry of surface water.

31. Basic principles of Soil stabilization
• Evaluating the properties of given soil
• Deciding the lacking property of soil and choose effective
and economical method of soil stabilization
• Designing the stabilized soil mix for intended stability and
durability values
• Effective utilization of locally available soils and other
stabilizing agents.
 Methods of soil stabilization
– Mechanical stabilization
– Soil cement stabilization
– Soil lime stabilization
– Soil bitumen stabilization
– Lime fly ash stabilization

32. Soil stabilization
• There are two methods used to apply soil stabilization materials.
• The two general methods of stabilization are mechanical and
additive.
• The effectiveness of stabilization depends upon the ability to obtain
uniformity in blending the various materials.
• Mixing in a stationary or travelling plant is preferred; however, other
means of mixing, such as scarifies, plows, disks, graders and rotary
mixers have been satisfactory.
• The method of soil stabilization is determined by the amount of
stabilizing required and the conditions encountered on the project.

33. Soil stabilization
 A) Mechanical method
– Mechanical stabilization is accomplished by mixing or
blending soils of two or more gradations to obtain a material
meeting the required specification.
– The soil blending may take place at the construction site, at a
central plant or at a borrow area.
– The blended material is then spread and compacted to
required densities by conventional means.
 B) Additive method
– Additive refers to a manufactured commercial product that,
when added to the soil in the proper quantities, will improve
the quality of the soil layer.
– Common additives which has been used to stabilize soils are
portland cement, lime, lime-cement-flyash and bitumen
alone or in combination.

34. Soil stabilization
• The selection and determination of the percentage of additives
depend upon the soil classification and the degree of
improvement in soil quality desired.
• Generally, smaller amounts of additives are required to alter
soil properties such as gradation, workability and plasticity
than to improve the strength and durability sufficiently to
permit a thickness reduction design.
• After the additives has been mixed with the soil, spreading and
compaction are accomplished by conventional means.

35. Soil stabilization
 Cement – soil stabilization, where portland cement can be used to stabilize and
strengthen certain type of soils. In this regard granular soils are very effective
for cement stabilization.
• The required quantity of portland cement is spread over the soil uniformly
which is to be stabilized, followed by mixing it into the soil, preferably with a
pulveriser-type machine to the specified depth, followed by compaction.
 Stabilization of soil with lime, because lime in its hydrated form rapidly
exchanges action leading to flocculation and agglomeration provided it is
intimately mixed with the soil.
• The clay type soil will then behave more like a silt type soil than clay type soil.
• This transformation starts within a hour of mixing and significant changes are
realised within a very few days depending upon the plasticity index of the soil
and the amount of lime used.

36. Soil stabilization
 Blending and mixing soils-
• This is one technique by which soil stabilization is achieved.
• If the soils found are to be heterogeneous or different in their original states
in the pit itself, it should be mixed thoroughly before being used in the fill.
• This can be accomplished during excavation itself by using equipment such
as a power shovel or a deep-cutting belt loader to excavate through several
layers in one operation.
• After these materials is placed on fill, further blending can be carried out by
several passes with a disk harrow.
 Types of stabilizers
• Some of the additives used in soil stabilization are cement, lime, flyash,
bituminous products and calcium chloride. Cement treated bases are the
most commonly used for the purpose of upgrading a poor quality soil. Soil-
cement is a mixture of pulverized soil and measured amounts of Portland
cement and water, compacted to a high density.

37. Mud wall building
• Earth is the oldest building material
• It use is as widespread as humanity as well. Nearly half the world’s
population lives in structures made with some kind of earthen
construction technique.
• In a present scenario, earthen construction remains the most
economically viable and popular method of construction.
• Other structures such as offices, stores, warehouses, etc., can also be
made using earth.
• The most obvious advantage of earth construction is the abundance of
the raw material – earth.

38. Mud wall building
 Other advantages of earthen construction include:
 High thermal insulating properties
 High sound insulation
Not susceptible to insects or rodents
No waste generated during construction
Inert – contain no toxic substances
Construction is inexpensive and simple
High workability and flexibility
Fire resistant

39. Mud wall building
The following are among the more popular types of earthen
construction:
- Adobe
- Cob
- Wattle and daub
- Cordwood or stone
- Rammed earth
- Straw – bale
- Compressed earth blocks

40. Mud wall building
• Adobe:
– Adobe is air/sun dried brick from mud
composed of inorganic soil and sand
– The soil must have minimum clay
content of 10%
– Fibers such as straw may also be
added to increase the stability of the
blocks as work well as binders.
– An adobe brick is typically 10 to 12
inches and weighs between 30 to 50
pounds.
– The bricks are stacked one over the
other and bonded using a mud mortar.
– Additives such as asphalt and fly ash
help to minimize its susceptibility to
moisture while giving it additional
strength.
- As adobe structures are
essentially stacks of mud, they
require protection from water,
especially rainfall that can wash
the structure away if due
precautions are not taken.

41. Mud wall building
– It is also essential that adobe walls be adequately tied using wood
beams at the top and base of the wall.
– These beams also serve as anchors for the roof trusses.
– Modern codes require that in areas with high earthquake risk, adobe
walls be reinforced with horizontal and vertical steel.
– Adobe structures have high fire resistance and its used to build multi-
million dollar homes and small hutments.
– Adobe is slowly but steadily losing its popularity to other technologies
but remains a useful solution where an eco-friendly solution is desired.

42. Mud wall building
Rammed Earth:
– Rammed earth involves the compacting of moist soil between rigid forms to
create monolithic earth walls with similar properties as that of adobe walls.
– The soil for rammed earth construction must have about 30% clay and 70%
sand and small gravel.
– Cement is sometimes added as a stabilizer. It is critical to ensure that the
moisture content of the wall is just right as if the mixture is too dry then it will
lead to a weak and crumbly wall.
– Too wet a mixture, on the other hand, will result in a mixture that will take
long to dry and harden.
– Like all earth buildings, rammed earth buildings must also be placed on firm
foundations made of concrete or stone.

43. Mud wall building
• The process of erecting the wall
includes raising the form and pouring
the earth into the forms and then
compacting it either by tampers or
pneumatically.
• The process results in a strong
monolithic wall.
• Rammed earth structures posses all the
qualities and shortcomings of other
types of earth construction.
• They too need surface protection
against moisture.
• The rammed earth walls have a
compressive strength of about 1000
psi and are therefore fairly strong.
• There are several rammed earth
structures around the world that have
stood the test of time fairly well.

44. Mud wall building
 Cob wall
– Cob was made by mixing the clay based subsoil with sand, straw and water
using oxen to trample it.
– The earthen mixture was then ladled onto a stone foundation in courses and
trodden onto the wall by workers in a process known as cobbing.
– The construction would progress according to the time required for the prior
course to dry.
– After drying, the walls would be trimmed and the next course built, with
lintels for later openings such as doors and windows being placed as the wall
takes shape.
– The walls of a cob house were generally about 24 inches thick, and windows
were correspondingly deep-set, giving the homes a characteristic internal
appearance.

45. Mud wall building
• The thick walls provided excellent thermal mass which was easy to
keep warm in winter and cool in summer.
• Walls with a high thermal mass value act as a thermal buffer inside the
home.
• The material has a long life span even in rainy climates, provided a tall
foundation and large overhang are present.
 Wattle and daub
- Wattle and daub is an ancient construction technique used to make
both interior and exterior walls.
- The look and feel of wattle and daub is quite distinctive and well
made, a wattle and daub home can be warm and very durable.

46. Mud wall building
• There are two stages to wattle and daub construction.
• The first is the creation of wattles, interwoven branches, lathes, or rods which
form a tight lattice.
• The wattle can be used to lay the groundwork for walls both inside and
outside a home or to fill in gaps between walls and ceiling timbers.
• Once the wattle is made, it can be covered in daub, a plaster like mixtures of
clays, mud, plant fibers and animal dung.
• After the daub sets, many people whitewash the resulting wattle and daub
wall to make it more weather resistant and to brighten it.

47. Mud wall building - Cordwood
• Walls are usually constructed such hat the pieces of wood are
protrude from the mortar by a small amount.
• Walls typically range between 12 and 24 inches thick, some
walls are as much as 36 inches thick.
• Cordwood homes are attractive for their visual appeal,
maximization of interior space (with a rounded plan), economy
of resources and ease of construction.
• Wood usually accounts for about 40-60% of the wall system, the
remaining portion consisting of a mortar mix and insulating fill.

48. Mud wall building
• There are two main types of cordwood construction,
a) Through wall and
b) M-I-M (mortar-insulation-mortar)
a) In through wall, the mortar mix itself contains an insulative material, usually
sawdust, chopped newsprint, or paper sludge in sometimes very high percentage by
mass (80% paper sludge/20% mortar)
b) In M-I-M, unlike brick or through wall masonry, the mortar doesn’t continue
throughout the wall. Instead three or four inch (sometimes more) beads of mortar on
each side of the wall provide stability and support, with a separate insulation
between them.
• Cordwood walls can be load-bearing or laid within a post and beam framework
which provides structural reinforcement and its suitable for earthquake prone areas.
• As a load-bearing wall, the compressive strength of wood and mortar allows for
roofing to be tied directly into the wall.

49. Mud wall building
 Straw-bale wall:
- Straw bale construction is a building method that uses bales of
straw as structural elements, building insulation or both.
- This construction method is commonly used in natural building or
“green” construction projects.
 Compressed earth blocks:
- Compressed earth blocks (CEB’s) are a relatively recent
technology and combine the nest characteristics of traditional
earthen technology and modern brick making processes.
- Earth is poured into moulds and compressed either manually or
mechanically.

50. Mud wall building
• The constituents of the earth mix are the similar to those of adobe:
clay, sand and additives or stabilizers such as cement or fly ash.
• CEBs structures have been found to be a lot stronger and more
weather resistant than traditional adobe structures.
• There are several manually operated and mechanical block
making machines available.
• CEBs are better than other earthen construction products as they
are more uniform and therefore easier to work with.
• Additionally, they help increase the speed of construction, which
is otherwise a limiting factor.

51. Mud wall building
• Also, the use of CEBs ensures a stronger structure that
possesses all the positive characteristics of earthen
construction and fewer shortcomings.
• Earthen construction is an eco-friendly and low cost
technology from the past and very relevant to the future.
• Several expensive homes have been built using these
technologies. The emphasis must be on low-cost housing
and earthen construction is an ideal technology to address
the global problem.

52. Mud wall building- surface protection
 Mud plaster: mud plaster has long been used as a surface coating.
Like adobe mud plaster is composed of clay, sand, water and straw or
grass and therefore exhibit sympathetic properties to those of the
original adobe.
• The mud plaster bonds to the adobe because both are made of the
same composition of materials.
• Once in place mud plaster must be smoothened.
• This is done by hand, deerskins, sheepskins and small slightly
rounded stones are used to smooth the plaster to create a polished
surface.
• In some areas, pink or ochre pigments are mixed into the final layer
and polished.

53. Mud wall building- surface protection
 White wash: whitewash has been used on earthen buildings since before
recorded history.
• Consisting of ground gypsum rock, water and clay, whitewash acts as a
sealer, which can be either brushed on the adobe wall or applied with large
pieces of coarse fabric such as burlap.
• Initially, it was considered as inexpensive and easy to apply.
• But its impermanence and the cost of annually renewing it has made it less
popular.
 Lime plaster: lime plaster has been widely used in the 19th century both as
an interior and exterior coating, is much harder than mud plaster.
• Its less flexible and cracks easily.

54. Mud wall building- surface protection
• To make the lime plaster adhere to adobe, walls are often scored
diagonally with hatchets, making grooves about 1-1/2 inches deep.
• The grooves are filled with a mixture of lime mortar and small chips of
stone or broken roof tiles. The wall is then covered heavily with the lime
plaster.
 Cement stucco: cement stucco came into use as an adobe surface coating
in the early 20th century for the revival styles of southwest adobe
architecture.
• Cement stucco consists of cement, sand and water and its applied with a
trowel from 1 to 3 coats over a wire mesh nailed to the adobe surface.
• This material is very popular because it requires little maintenance when
applied over fired or stabilized adobe brick and it can be easily painted

55. Mud wall building- surface protection
• It should be noted that the cement stucco does not create a bond with
unfired or unstabilized adobe.
• It relies on the wire mesh and nails to hold it in place.
• If nails doesn’t bond with the abobe then the firm surface cannot be
guaranteed.
• Even when very long nails are used, moisture within the adobe may cause
the nails and the wire to rust, thus losing contact with the adobe.
 Other traditional surface coatings: These items include paints(oil base,
resin or emulsion), portland cement washes, coatings of plant extracts and
even coating of fresh animal blood.
• Some of these coatings are inexpensive and easy to apply, provide
temporary surface protection and are still available to the adobe owner.