Introduction to Interlocking bricks. Composition and Manufacturing of Interlocking bricks. Interlocking Bricks with their application in Civil Engineering. Types/Design of Interlocking bricks used in Civil Engineering. Advantages and Disadvantages of Interlocking bricks.

1. “Interlocking Bricks”
Introduction:
➢ Interlocking Bricks are made by
mixing Soil, Sand and Cement
and compressing it in a machine.
It is an Earthquake resistant
technology recommended. It is
fast to build with and on average
25% less cost compared to fired
bricks.
➢ Interlocking bricks are the
enhanced form of conventional
clay bricks. Interlocking bricks
are compressed and stabilized
earth bricks which contributes to
strength of the structure. Each
brick is constructively designed
to lock itself to the other bricks
around without the use of mortar.
➢ The self-locking is achieved using shear-key and lock mechanism. Based on the
design, the shape of shear-key will vary and a complimentary lock is provided on the
opposite side of brick. Load transfer is achieved by shear transfer and gravity.
➢ They are usually not subjected to baking. Interlocking bricks come in various sizes
and locking systems depending on the supplier.

2. 1
Why to Use Interlocking Bricks:
• Can be produced at or near the site, reduced transportation cost.
• Green technology, zero carbon emission.
• Energy Efficient.
• Uses local available materials.
• Reduces the need for skilled labor.
• Maximize the use of unskilled labor.
• Faster to build, shortens construction time.
• Creates local employment.
• Permits self-help construction or community based projects.
• Can be used to build all types of buildings.
Composition:
High quality interlocking bricks are made of cement, sand and stone dust or sand mixed
together in appropriate proportions.
Manufacturing:
The required materials are batched and mixed proportionately. Once the required mix is
prepared, it is then compressed to form bricks with desirable interlocking patterns. The
compression is achieved by using hydraulic compression system. The bricks are then
subjected to curing for about 7 days. Once the curing is done, the cement sets and bonds with
sand adding to the stability of the brick. Whereas the soil compression adds strength and
density to the brick. The interlocking bricks come in different designs, finishes and patterns.
Manual interlocking Brick making machine

3. 2
Manual manufacturing of interlocking Brick
Mud soil clay cement interlocking brick making machine

4. 3
Production Process:
The key points of production process is slightly mentioned below;
• Selection of raw materials.
• Preparation of Mixes.
• Filling mold box with mixes.
• Compression.
• Removal of brick and placing it on a pallet.
• Air curing / storage.
• Water curing.
• Testing.
Interlocking Brick Designs:
Interlocking bricks comes in various shapes, designs and sizes.
The designs and sized depend upon the desire and requirement.
Some of the common designs are shown below;

5. 4
Advantages:
i. No requirement of Plaster (Minimization of Cost):
Plastering can be time consuming and costly in case of conventional wall construction.
Plastering of walls can be completely eliminated by using fair faced bricks of your
choice available in the market. If required the walls can be given a smooth finish by
applying a thin layer of paint. Since these bricks are self-designed that gives a neat
finish, the maintenance cost is minimized.
ii. Cooler Interior Temperature (Minimized Cost and Energy Consumption):
High compacted bricks generally result in higher density, which in turn converts itself
into high thermal mass. Henceforth, the walls made of high compacted bricks typically
furnish warm interiors. Interlocking bricks are less heat intensive. The tests have
shown that interlocking bricks provides a much cooler interior (3o
C to 5o
C). This
enables lesser/no use of air conditioners resulting in minimized energy consumption
and more cost saving.
iii. Fewer Labor Required:
In case of Conventional brick laying, skilled labor is required for checking water level,
spirit level and various other operations. Therefore a layman or an unskilled labor may
find it difficult to learn the conventional methods of construction. Whereas
interlocking bricks construction enables an unskilled labor to easily follow up on the
construction procedure. It also provides various opportunities for an entrepreneur.
iv. Earthquake Resistant:
• During earthquakes, there are various stresses acting on the structure.
Conventional bricks are not fully equipped to transfer the seismic loads
throughout the structure since the only medium of load transfer is the mortar.
If the mortar fails then the whole structure fails under seismic forces.
• Interlocking bricks are an effective and proven earthquake resistant
construction materials. The self locking pattern of the bricks enables the
seismic forces to travel across the whole structure equivalently.
• When building we utilize the Interlocking Brick Masonry and reinforce the
walls with rebar, both horizontally and vertically, adding to the strength and
making the structure earthquake resistant.
• Vertical rebar are put in each corner, at doors and windows and evenly spaced
throughout the walls. This is then connected with horizontal seismic bands
making the whole structure interconnected and earthquake resistant.
v. Overall Minimization in Cost:
Since there is no use of mortar in the construction process, the cost of buying cement,
sand, mortar and stone dust can be neglected. Also the cost for transportation can also
be immensely reduced along with the cost on skilled labor. It does not require
plasterwork, minor bar bending work, lesser cement and fewer laborer hence
contributing to the overall cost reduction of the construction project.
vi. Time Efficient:
It is proved as the most time efficient way of construction. The normal conventional
bricks has to be cured for about 21 days whereas the self-locking bricks require only

6. 5
7 days of curing. In addition to that, time required for setting and curing of the structure
can be diminished completely. By eliminating all the time consuming tasks, the project
can be completed faster.
Disadvantages:
i. Since there is no plasterwork provided, rain water might into the lines making it a
hostage for insects and other undesirable things.
ii. Due to the action of weather, disintegration of the bricks might also occur especially
in the corners.
iii. The color of the brick changes if the rain water enters through the gaps.
iv. As the interlocking bricks alone are not enough to hold all the forces acting on the
structure, it is not advised for building having more than two stories.
Applications:
Interlocking bricks can be used in;
• Residential Buildings
• School Buildings.
• Health Clinics.
• Office Buildings.
• Resort Villas.
• Self-help or Community based projects.
• Pavments/Walkways.