Download RESEARCH PROPOSAL

MTECH RESEARCH PROPOSAL
ON
THE DESIGN OF A NEW FUTA GUEST HOUSE
(The use of interlocking blocks in achieving aesthetics and
stability in Public housing)
By
BANKOLE-OJO, OLATUNBOSUN
Arc/ 01 /9214
DEPARTMENT OF ARCHITECTURE, FEDERAL
UNIVERSITY OF TECHNOLOGY, AKURE
LECTURER; PROF. (ARC) OGUNSOTE.O.O
DATE: APRIL 2008
INTRODUCTION
Starting from the early stage of man’s evolution, shelter has remained one inevitable
need. This is evident as can be seen in the order of priority of man’s basic need by
which housing has been said to have ranked second after food with clothing as the
third (Aribigbola 2000).The quest for housing is continuously on a rise as there is
increase in human population; this fact serves as a basis for the possibility of using
different materials at achieving this purpose due to different locations and
innovations.
In the recent times however, human taste and needs have transcend beyond just
having a structure as a shelter, but has got to a level of concern for durability,
flexibility, functionality, short construction processes, cost effectiveness, aesthetics
and in most cases comfortability for the various structures built. However, the need
for change and improvement brings about the search for some means (technology) of
achieving some building elements made from existing or from an entirely new
building construction material.
Building Material is defined as any one of various substances out of which buildings
are constructed. (Microsoft Encarta 2007).These materials include; Laterite, Stone,
Concrete, Timber, Steel, Plastics, Bamboo, and Glass which are used for various
building construction purposes Theses materials serves as the most common and the
most used construction materials in the construction industry to make different
building elements. Building elements are those made from building materials that
forms the physical component parts of the construction such as sandcrete blocks,
polysterene panels, laterite blocks, walls and floor tiles, column and beams made from
concrete or timber materials etc. However, researches are constantly going on in the
quest for finding alternatives to these existing common materials and also ways of
improving on the existing ones to improve their quality, reduce their cost, improve
their inherent properties for higher and faster processing of the construction work by
finding newer approaches for construction activities and solutions to constrains
encountered which also defines the quality and quantity of the building elements
made from these materials. One of the results of such researches is the interlocking
block which is a relatively new material for masonry walls construction as an
alternative to sandcrete blocks and laterite blocks as a result of improved or
advancement in technology.
PROBLEM STATEMENT
The inherent strength of interlocking blocks accompanied with its lightness and form
it gives as a highly competitive masonry building element to concrete blocks as it
applies to public housing is one of the main cause for this research
AIM AND OBJECTIVES
This research aims at studying how the use of interlocking blocks in public housing
construction can affect the structural and aesthetical forms of such buildings. In view
of achieving this aim, the following objectives are formulated

Determining the effect of the material on building

Its preference to other building construction materials

Knowing how well it substitutes the se of concrete (sandcrete) blocks and
laterite blocks in masonry building construction.

Its structural requirements and cost implications when used in construction

Its application as related to public housing
RESEARCH HYPOTHESIS

The use of interlocking blocks in building has a significant effect on the
aesthetics of the building

The use of interlocking blocks affects the form of the building

The construction cost with interlocking blocks is cheaper compaired with
those of sandcrete blocks.

Houses built with interlocking blocks can be more structurally sound than
those built with sandcrete blocks.

There’s no significant difference in the level of provided by interlocking
blocks-built houses and sandcrete blocks-built houses
SCOPE OF STUDY
This research will be limited to the use of interlocking blocks in the Nigerian building
construction industry with a special interest on its application on public housing in
Akure.
LITERATURE REVIEW
ORIGIN OF INTERLOCKING BLOCKS
The research activities that ultimately led to the development of the interlocking block
technique, which is gaining popularity in Thailand, as well as Malaysia and the
Philippines, date back to the 1960s. In these countries, houses in the rural areas were
traditionally built of timber, which was readily available in the extensive forest areas.
However, the alarming rate of deforestation in Thailand - from 70% forest cover in
1936 to about 55% in 1961 (now it is less than 30%) - led the government to initiate
research into alternative materials for building construction in the rural areas.
Initially, research undertaken by the Thailand Institute of Scientific and Technological
Research (TISTR), Bangkok, focused on soil-cement blocks made with the CINVARam manual block press (which was developed in Colombia in 1956). The
demonstration houses built with these blocks were cheaper than timber houses, more
durable, resistant to water, fire and termites, and aesthetically appealing. The
disadvantages, however, were that the blocks were relatively heavy, and building
construction required a certain amount of masonry skills. Furthermore, the mortar
joints consumed a considerable amount of cement and construction time was
relatively long. (Steve 98)
These disadvantages led to the development of the interlocking block technique by the
Human Settlements Division of the Asian Institute of Technology (HSD-AIT),
Bangkok, in co-operation with TISTR, in the early 1980s. The first demonstration
house using interlocking soil-cement blocks was built in Thailand in 1984. Between
1986 and 1990, the Post Graduate Centre Human Settlements (PGCHS), of the
Catholic University of Leuven, Belgium, assisted these institutions in optimizing the
inter- locking block technique, which has now reached a high degree of maturity
internationally. (Steve 98)
TYPES OF INTERLOCKING BLOCKS
A variety of interlocking blocks have been developed during the past years, differing
in material composition, shape and size, depending on the required strengths and uses:
The classification of interlocking block types are based on the:
Material used in production
Shapes and sizes of blocks
TYPES ACCORDING TO MATERIALS USED
Soil-cement blocks
Depending on the soil and cement qualities, the cement-to-soil ratio usually lies
between 1: 6 and 1: 10, by volume. (Laboratory tests are essential).
Rice husk ash (RHA) cement blocks.
The cement-to-RHA ratio is generally 1: 4, by volume. Two types of blocks can be
produced:
white blocks, with a compressive strength of 4 N/mm², using ash (amorphous silica)
from field kilns, burnt below 900°C;
black blocks, with a compressive strength of 1.4 N/mm², using boiler ash (crystalline
silica), burnt up to 1200°C;
Concrete blocks
A typical mix proportion of cement-to-sand-to-gravel is 1: 5: 3.
TYPES ACCORDING TO DIFFERENT SHAPES AND SIZES
Full blocks (300x 150x 100 mm) for all standard walls (single or double brick thick)
Half blocks (150 x 150 x 100 mm), which can be moulded to size, or made by cutting
freshly moulded full blocks in half.
Channel blocks, same sizes as full and half blocks, but with a channel along the long
axis, into which reinforcing steel and concrete can be placed to form lintels or ring
beams.
The vertical sides of the blocks can be flat or have recesses, and the vertical grout
holes can be square or round.
PRODUCTION OF INTERLOCKING BLOCKS
Interlocking blocks are produced in special moulds, in which compaction can be done
by hand or mechanically, depending on the type of block, material used, required
quality and available resources. The blocks can be made directly at the building site,
or on a larger scale in a production yard.
Soil-cement blocks are commonly manufactured in manually operated blockpresses
(modified CINVA Rams). Two workers prepare the soil mix, shovel it into the mould
box and close the lid. Compaction is done by a third worker, who pulls down a long
steel handle (lever arm), which pushes up the base plate. After opening the lid and
ejecting the block, it is removed by a fourth worker and stacked in a shaded place for
curing and hardening.
Rice husk ash and concrete blocks need tamping, or better still vibration, for proper
compaction. Therefore, the manual block press is not suitable. Manual tamping is
done by jabbing the mix with a piece of wood or dropping the filled mould several
times on a hard surface. Higher compaction and greater strengths are achieved by
placing the mould on a vibrating table, or holding a portable vibrator against the sides.
After demoulding, the blocks are carried away on pallets for curing.
THE PRINCIPLE BEHIND THE HOLLOW INTERLOCKING BLOCKS
A technology using reinforced hollow concrete block has been developed all over the
world since a while. Its principle is to reinforce the masonry by grouting a concrete
into the holes of the blocks where stands a steel rod at the critical locations (Corners,
ends, near openings, etc,). Horizontal reinforcements are also cast in blocks with a U
shape. The technology using Hollow Interlocking Compressed Stabilised Earth
Blocks (HI CSEB) is based on the same principle: to reinforce horizontally and
vertically the masonry with Reinforce Cement Concrete (RCC) members.
THE INTERLOCKING BLOCK TECHNIQUE
The concept of interlocking blocks is based on the following principles:

The blocks are shaped with projecting parts, which fit exactly into depressions
in the blocks placed above, such that they are automatically aligned
horizontally and vertically - thus bricklaying is possible without special
masonry skills.

Since the bricks can be laid dry, no mortar is required and a considerable
amount of cement is saved.

Each block has vertical holes, which serve two purposes: 1. to reduce the
weight of the block, and 2. to insert steel rods or bamboo for reinforcement,
and/or to pour liquid mortar (grout) into the holes, which run through the full
height of the wall, thus increasing its stability.

The length of each block is exactly double its width, in order to achieve
accurate alignment of bricks placed at right angles.
REQUIREMENTS FOR HOLLOW INTERLOCKING BLOCKS
Interlocking blocks can resist disasters (Cyclones, earthquakes and floods), provided
that they are hollow, so as to be reinforced with Reinforced Cement Concrete (RCC),
at regular intervals. A hollow interlocking CSEB for earthquake resistance must
satisfy these requirements:
Extreme consistency in height (1 mm difference maximum is allowed).
Self-aligning to reduce time-wasting adjustments.
Blocks should be hollow and the vertical holes and U shaped blocks should allow
casting RCC, according to requirements: To reinforce regularly the masonry vertically
and horizontally.
The interlocking keys must interlock transversally and longitudinally to the wall.
They should interlock especially well in the length of the wall, which is subject to the
shear stress of the earthquake.
Every course must interlock with each other as well as the header of every block in
length: to increase the shear strength of the masonry.
Good seating of the blocks on top of each other for properly transmitting the load
bearing: All the block area, including the key, must transmit the load.
A binder must bind them: they must not be dry stacked, as the aim is to get a
homogenous masonry.
The binder should be a cement-sand mortar of 5 mm thick. It should be quite fluid in
order to be workable.
The mould must allow manufacturing of full size blocks but also 3/4 and 1/2 sizes. The blocks
must not be cut to match the bond pattern, which will be detrimental to the accuracy, strength and
quality of the masonry.
APPLICATIONS OF INTERLOCKING BLOCKS IN HOUSING
Wall construction
Before placing the first course in a mortar bed, the blocks must be laid dry on the
foundation around the entire building, in order to ensure that they fit exactly next to
each other (leaving no gaps), and that an exact number of full blocks are used,
otherwise the system will not function. When laying the first course in the mortar bed,
care must be taken that the blocks are perfectly horizontal, and in a straight line, or at
right angles at corners.
Once the base course is properly hardened, the blocks are stacked dry, with the help
of a wooden or rubber hammer to knock the blocks gently into place. Up to 10 layers
can be placed at a time, before the grout holes are filled with a liquid mortar - 1 part
cement to 3 parts sand (or soil or rice husk ash) to 1 part water.
It is advisable to place channel blocks around the building, at window sill height, to
install a ring beam. They should also be placed directly above doors and windows to
install lintels, and directly below the roof to finish the walls with a ring beam. For
increased structural stability, especially in earthquake regions, steel rods or bamboo
should be inserted in the vertical grout holes, especially at corners, wall junctions and
on either side of openings.
Interlocking blocks are ideally suited for load-bearing wall constructions, even for
two or more storeyed buildings, provided that the height of the wall does not exceed
20 times its thickness, and wall sections without buttresses or cross walls do not
exceed 4.5 m length (to prevent buckling).
Though less economic, non-load bearing constructions are more common. The walls
are constructed in the same way as load- bearing walls, but merely serve as infills
between the reinforced concrete frame (post and beam) structure, which supports the
roof. Care must be taken to achieve a good bond between the walls and frame-work.
Building design
Almost any type of building can be constructed with interlocking blocks, the main
design constraints being that the plan should be rectangular and all wall dimensions
and openings must be multiples of the width of the block type used. All other
principles of design and construction, such as dimensioning of foundations, protection
against rain and ground moisture, construction of ceilings and roofs, and the like, are
the same as for other standard building types.
ADVANTAGES AND DISADVANTAGES OF THE USE OF HOLLOW
INTERLOCKING BLOCKS
Advantages

The advantage of hollow interlocking CSEB, compared to hollow concrete
blocks, is that they offer keys, which interlock in the other blocks. Thus these
walls offer more resistance to shear and buildings would be even stronger.

They would better resist earthquakes and without major damages.

Compressed stabilised earth blocks have another advantage: they are in most
cases cheaper and they are always more eco-friendly than concrete blocks.

The materials required for block production and building construction are
usually locally available in most regions; therefore, in areas in which timber is
scarce and expensive, construction with interlocking blocks has environmental
advantages (no deforestation, low energy requirement for block production
and transportation).

Unlike the case of timber constructions, termites cannot cause damage to the
blocks.

Compared with conventional masonry, the dry assembly of interlocking blocks
saves construction time and a large amount of mortar, which would otherwise
be required for the horizontal and vertical joints.

Without the need for high-waged skilled masons (except for the base course),
by saving cement (less mortar) and with the speed of construction, the
building costs are lower than for standard masonry construction. Additional
costs are saved by building load bearing walls, instead of infill walls between
a structural framework.

The structural stability and durability of interlocking block constructions can
be far greater than for comparable timber constructions. Grout holes and
channel blocks provide means to insert steel reinforcements in vulnerable parts
of buildings for increased wind and earthquake resistance.

Interlocking blocks can be produced on a small scale on the building site (for
self-help construction), or on a large scale in centralized production units.

The interlocking block technique is suitable for the construction of multistoreyed buildings, in the same way as for standard masonry constructions
Disadvantages

The technology being relatively new, people may be reluctant to apply it.
Hence, a well co-ordinated dissemination strategy to introduce it to potential
builders is vital.

Although skilled masons are not needed for constructing walls, a certain
amount of training is required to ensure that the walls are properly aligned and
no gaps are left.

Also in the production of the blocks training is needed not only in determining
the correct type of soil, correct mix proportion and moisture content, but also
in producing uniform sized blocks (that is, avoiding under or over-filling the
block moulds before compaction).

Even with the greatest care in assembling the walls, the joints are not entirely
resistant to wind and rain penetration, therefore, plastering the interior wall
surfaces is usually necessary.

Compressed stabilised earth blocks have a poor bending strength but this is not
so critical because the block itself will not bend but the masonry will do.
CSEB have very poor shear strength, which is critical in the case of
earthquakes. Interlocking blocks will not have a stronger shear strength
compared to ordinary CSEB. But the key effect will increase the shear
strength of the masonry if the cohesiveness of the material is high enough to
keep the link between the key and the body of the block. (Especially shocks
and vibrations of an earthquake).
RESEARCH METHODOLOGY
This section presents a clear insight to the study as well as the methodology that will
be adopted for the research. The term methodology describes the specification of
procedure for the collection and analysis of data necessary to solve the problem at
hand. Methodology is described as the set of methods or systematic approach towards
solving a particular problem through data collection, analysis and presentations.
PURPOSE OF RESEARCH
Researches are often carried out in an attempt to survey, analyze and replan an
existing situation to produce positive effects. This is achieved through systematic
process of data collection, presentation, analysis and interpretation (Okoko, 1998).
The deductions from the research are vital tools for planning proposals and are useful
for solving the problem in view.
TYPES OF RESEARCH
The various research methods adopted for this research are as follows;
Survey Research
This is a form of research that require regular visitation to the study area in other to
gather necessary information on the context of the use of these building construction
materials.
RESEARCH INSTRUMENTS
These are practically the methods of acquiring information from the field about the
subject of interest from the different available sources. Those adopted in this research
study are as follows
Observation
This method entail personal visitation to the site or areas where necessary information
can be obtained for the purpose of the study. Verbal approach, conversation or
interviews with anybody is not required for this purpose. The researcher is expected to
watch the happenings at the area of study and record the observable phenomenon. The
observed issues can either be behavioral (where the observer act as participant in
other easy access to necessary information) or non behavioral (where the observer is
expected to watch and observe what is happening). In this study, different structures
both international and home were studied so as to extract results of findings.
Interviews
This is a method of having a direct conversation with the source or respondent. It
involves the preparation of a list of relevant questions which are to be asked from the
respondents. The reliability of this method lies in the fact that the verbal and non
verbal responses of the respondent are recorded and questions outside the ones
already listed can be asked. Relevant information were gathered from conversation
with the professionals in the construction industry
Questionnaire
These are set of well structured questions designed by the researcher to gather specific
information on a particular matter from the respondent which are later collected,
analyzed and presented. This can be referred to as a series of simple well structured
questioned arranged to gather the required information. It is advantageous in that it
covers a very large population than interview and it is also for use in testing of
hypothesis time saving.
Ocular/ Visual Presentation
These are area photos taken from the area to provide first hand information on the
issue. It helps in the provision and visualization of the situation on the on the research
ground.
TYPES OF DATA
Data is a word referring to all the necessary raw information collected from the
various sources on the site. The types of data collected are; Primary data and
secondary data
Primary Data
These are often referred to as raw data obtained from the above mentioned tools. The
questionnaire administered for the purpose of this study was designed with series of
relevant questions with the option of filling the gaps. The questionnaires are to gather
information about the use and practice of interlocking in the construction industry,
how often they are used, the preference for their uses, the techniques required for their
uses and the possibility of improved uses with improved technological development
in the future, and how have they affected the forms of building in the 21st century
architectural practice. This information was obtained from mainly the practitioners
which include: the architects, structural engineers, quantity surveyors and the
contractors in the building construction industry and the end-users
Secondary Data
These are the processed information and kept in record for different purposes. They
exist in published materials and are merely collected for the purpose of research. In
this regard the researcher will explore the general use and production of interlocking
blocks in the state
EXPECTED CONTRIBUTION TO KNOWLEGDE
This research will serve as an eye opener to the various advantages accompanying the
use of interlocking blocks in housing construction. It will also create a form of
diversification and variety in the choice of building materials used for construction in
the university campus.
This research will also help to see the application of interlocking blocks as one of the
major building materials that is cost effective in archieving aesthetics and form
without much spaending on finishings.
It will also serve as a gateway to further researches on the possibilities of the use and
application of this material in high rise administrative buildings, industrial buildings,
commercial buildings etc other than for housing purposes.
REFRENCES
Angus J MacDonald (1997): Structure and Architecture. Architectural Press, Reed
Educational and Professional Publishing Ltd.
Colin Caborn, Ian Mould and John Cave, (1989): Design and technology. Thomas
Nelson and Sons.
Fadamiro J.A & D.R Ogunsemi, (1996): Fundamental of Building Design,
Construction and Materials, Fancy Publications Ltd. Ile Ife.
Illston, J. M. (1994): Construction Materials, their nature and behavior.2nd Edition.
Okoko E. (2000): The Effective Housing in the 21st Century Nigeria. Akinbamijo et al
(eds). Akure: environmental forum: federal university of technology, Akure.
Smith Andres. (1997): Materials of Construction. 4th Edition. McGraw Hill
International Editions.
Internet References
Martini. M (2000) Interlocking block construction in Thailand retrieved from the
internet April 1st 2008 at www.kthaicon.com
Steve .B (1998), Building with interlocking blocks, journal of building materials
retrieved from the internet April 1st 2008 at www.forester.net