A brick is a construction material typically made of shale, clay or concrete. It is a rectangular or square-shaped material used for various purposes such as partitions, foundations, building walls etc. It is the most popular material in the construction industry, known for its durability, strength and fire resistance.
Besides, brick masonry is a construction technique that involves the arrangement and bonding of bricks using mortar to create walls, columns, facades and arches. It is a widely used method in residential, commercial and industrial buildings that offers several advantages such as durability, fire resistance and aesthetic appeal.
Brick masonry is an ancient and significant method all over the world. The conventional methods for bricks have irrefutable drawbacks. However, in order to overcome the problems with ancient methods, the techniques of manufacturing the bricks have changed for the last two decades. Because of this recent change, two types of bricks were developed i.e. solid bricks and interlocking bricks.
In this blog, we will only be discussing about interlocking bricks. Let’s have a look at the history of interlocking bricks.
History of Interlocking Bricks
In the early 1900s, the first introduction of interlocking bricks was started with the construction of toys for children’s Mckusick (1997), Love and Gamble (1985). Among the first inventors of toy systems that contributed to the interlocking bricks were :
(i) Frank Hornby (1863 – 1930) invented Meccano sets.
(ii) A.C Gilbert (1884 – 1962) invented Erector sets.
(iii) Charles Pajeau (1913) invented Tinka Toy Construction sets.
(iv) John Lloyd (1920) invented Lincoln Logs.
(v) Ole Kirk Christiansen (1891 – 1958) invented Lego.
In the beginning, toy mechanisms were primarily designed to teach creativity and serve as a learning tool for scientific, engineering, and architectural principles. The original materials used for constructing toys included tin, metal, wood, and clay. However, nowadays, plastic is the most commonly used material for making toys. Among these different toy systems, Lego bears the closest resemblance to walling.
The concept of interlocking brick construction for toys, known as Automatic Binding Brick, was first developed in Denmark in 1949. In 1951, the Automatic Binding Brick was renamed “Lego Mursten” or “Lego Brick” in English. It was first produced commercially in 1958.
The 1958 version of interlocking bricks introduced a clever design with stubby cylinders and matching studs on the surface. This design allowed Lego bricks to securely connect to one another. In 1967, a simplified version called “Duplo” bricks was launched, offering a wide range of sizes, shapes, and colors. These bricks formed the foundation for mortarless technology utilizing interlocking bricks or blocks.
Since the 1970s, the concept of interlocking mortarless bricks or blocks for house construction has been pioneered in various regions, including Africa, Canada, the Middle East, and India. These bricks are typically made from sand-cement, stabilized soil, or burnt/baked soil.
What is Interlocking Brick?
Interlocking brick stand apart from conventional blocks due to their distinctive feature : the absence of mortar between the layers during construction. This characteristic brings numerous advantages, including faster construction and reduced dependency on skilled labor. The bricks are simply dry assembled and stacked on top of each other, speeding up the building of walls and partitions. However, it’s important to acknowledge some challenges associated with interlocking blocks. These include lower strength compared to traditional bricks, higher water absorption, lower fire resistance, and higher porosity. These factors should be taken into consideration when using interlocking blocks in construction projects to ensure appropriate measures are taken to address these limitations and ensure the overall durability and safety of the structure.
Due to profitability, effectiveness, and diminishment in a particular work, interlocking bricks have gained immense popularity. Therefore, the utilization of interlocking bricks has increased significantly over the years for supportable and sustainable buildings. When compared to conventional bricks, interlocking bricks are unique as there is no need of filling mortar between the blocks during construction.
Advantages of Interlocking Bricks
- Interlocking bricks require no/very minimal mortar to be filled between the block layers during the construction process, making the process faster and requiring fewer skilled workers.
- Interlocking bricks have higher field productivity and efficiency, and reduce the requirements for highly specialized work teams.
- Interlocking bricks don’t require mortar, thus reducing construction cost and time.
- Interlocking bricks reduced the dependence of skilled labor.
- Interlocking bricks have been studied for their structural behavior as load-bearing and non-load-bearing elements, and have been found to be efficient and durable.
Interlocking bricks, despite their numerous advantages, also have certain disadvantages that need to be considered in construction projects.
- Interlocking bricks exhibit lower strength compared to conventional bricks, which can affect the overall structural integrity of the building.
- Interlocking bricks have a tendency for high water absorption, making them more susceptible to damage from moisture, leading to potential issues such as cracking or deterioration.
- Interlocking bricks have lower fire resistance, posing a safety concern in case of fire incidents.
- Due to higher porosity, Interlocking bricks have increased permeability, allowing moisture and other substances to penetrate more easily, which can lead to long-term durability issues.
Types of Interlocking Bricks
Over the past years, various kinds of interlocking blocks and bricks have been manufactured, each differing in material composition, size, and shape. These variations are determined based on specific requirements for strength and intended use. These comprise of “Alan block, Hydraform, Sparlock system, Meccano system, Sparfil system, Haener system, Putra block system,Solid Interlocking blocks (SIB)”etc., which are a change over the conventional bricks and blocks.
1) Interlocking Hollow Bricks
- Interlocking Hollow Bricks are made of cement-sand/aggregate in the ratio of 1:10.
- Interlocking Hollow Bricks are of two types : (a) Alternate face-shell components (known as the Sparlock System) and (b) Projecting lug system components (known as the Haener System).
- The general size of Interlocking Hollow Bricks is 400 x 200 x 200 mm.
- The Sparlock system allows placement only of vertical reinforcements, while the Haener system provides for both horizontal and vertical reinforcements.
2) Thai Interlocking Bricks
- It was developed in early 1980s by Human Settlement Division of the Asian Institute of Technology (HSD-AIT), Bangkok, in co-operation with Thai Institute of Scientific and Technical Research (TISTR).
- It is produced using modified CINVA-Ram manual press developed in Colombia in 1956 (VITA 1975).
- This brick comes with dimension 300 x 150 x 100 mm.
- This brick has vertical holes throughout the height serving purposes such as reduced weight, can house reinforcement or mortar to increase wall stability or may be used for electrical conduits.
- The strength of interlocks depend on surface render, or on grout filled into vertical holes with additional reinforcements if need arises.
3) Solbric Interlocking Brick System
- It is a solid interlocking brick formed by pressing on their ends (the compacting stroke moves parallel to the longer side), with guided or controlled width and height.
- SOLBRIC interlocking brick system creates small empty spaces between layers of materials in a wall, which can be used to install pipes or conduits. Additionally, these spaces can also be utilized to add reinforcements at specific points in the wall, making it stronger and more structurally sound. This design feature allows for the convenient integration of utility systems and targeted reinforcement within the wall structure.
- The SOLBRIC interlocking brick system appears to be user-friendly. The design of the bricks and machine-produced components allows for the construction of external walls with relative ease. However, it should be noted that this system lacks the capability to connect partitions, such as creating tee or cross joints. Consequently, it is primarily suitable for constructing standalone external walls rather than complex internal structures involving intersecting walls.
- The flat internal surface of SOLBRIC reduces the thickness of required plaster mortar and the external pointed joint makes the external appearance attractive.
- The size of the brick is 250 x 200 x 100 mm.
4) Hydraform Inerlocking Brick System
- Hydraform is the most basic kind of interlocking block, which has a simple shape. When these blocks are interlocked, they create a joint with a tongue and groove pattern on the sides, top, and bottom.
- These blocks are designed to slide horizontally along the layers, allowing them to be pushed closer together to create tighter vertical alignments.
- The stability of the wall built from the Hydraform Bricks is not provided by the locking mechanism but by the width and weight of the brick.
- The dimension of Hydraform Interlocking Brick is 240 x 220 x 115 mm.
- When Hydraform bricks are laid perpendicular to each other, some ‘shaving’ or ‘chopping’ is required.
- The longitudinal course joints of the Hydraform bricks have a small gap of 1-1.5mm between the tongue/ridge and groove of the adjoining blocks. This intentional clearance or “play” is designed to allow for easier sliding of the blocks in a horizontal direction. It simplifies the process of laying the blocks and helps achieve tighter vertical alignments (perpends) when constructing walls.
5) Bamba Interlocking Brick System
- The top and bottom faces of a brick has negative symmetry.
- Due to its unique shape, Bamba bricks provide better interlocking than others.
- The production of Bamba bricks require high precision in selection of materials and accurate machinaries to mould.
- The dimension of brick is 300 x 150 x 120 mm.
6) Tanzania Interlocking Brick System
- This system is an improvement of Bamba System.
- Some interlocking improvements were made such as : (a) The locking knobs and depression are two as for the Auram type, but they are of pyramid shape with holes running through the centre of the knobs. (b) The brick is chamfered to the front and back edges, providing pointed horizontal and vertical wall joints. This chamfer, gives a good key to the plaster if plastering is needed (the bricks from the machine are normally smooth enough to provide good finishing without plastering). The chamfer also reduces corner friction during brick production; thus reducing the ejection force required.
- TIB bricks have a good locking mechanism but need to test the strength of knobs and webs.
- Vertical joints in TIB bricks are not secure.
- TIB bricks should have a groove for mortar placement.
- TIB bricks cannot meet all building industry needs:
- Various brick bonding joints cannot be created.
- Wider pillars cannot be attached to walls.
- Thicker walls cannot be built.
- Different wall configurations (circular, polygonal, etc.) are not possible.
7) Mecano Interlocking Brick System
- In this type of brick system, there is no interlocking provided despite they are simply stacked on each other.
- All the voids provided in the blocks are then grouted after the placement of the horizontal and vertical reinforcement in their positions.
- The bricks should have accurate dimensions and smoothness to ensure proper alignment and aesthetic view.
- The shape of the blocks allows two-way hollow cores for introducing the reinforcement.
- The hollow cores are then filled with concrete grout to complete the reinforced masonry wall.
8) H-Block and W-Block Interlocking Brick System
- These two types of interlocking brick system was developed by Drexel University for reinforcement construction work, which is able to resist earthquakes.
- The H-block system comes with tongue and groove interlocking on both the bed and head joints. It can be reinforced in both vertical and horizontal directions. Partial grouting is required to ensure the stability of the wall during construction prior to full grouting.
- The W-block system shows the possible horizontal and vertical reinforcement and the stacking of the units. The horizontal joints between the courses are staggered by using different block heights. Three different types are required to construct the walls. However, the vertical joints are made continuous along the height of the wall.
9) Putra Interlocking Block System
- Putra Interlocking Blocks has been developed to achieve the objectives of ease of production, constructability, and modular coordination requirements.
- Putra Interlocking Blocks consist of three different configurations: Stretcher Block, Corner Block, and Half Block.
- The interlocking mechanism of these blocks ensures stability in any direction by providing a 20 mm protrusion.
- The Stretcher Block is the main unit used for constructing the wall.
- The Corner Block is used at junctions and ends of the walls.
- The Half Block is used to complete courses of the wall, ensuring staggered vertical joints.
- The interlocking mechanism eliminates the need for mortar layers, increasing construction speed.
- The self-aligning features further enhance the speed of construction.
- The compressive strength of the tested individual Putra blocks is 94.6–118% of the concrete cube cast using the same mix.
In this blog we have gone through advantages, disadvantage and types of interlocking bricks along with their specifications. The interlocking bricks require less skilled labor and the construction time is also reduced thereby making these bricks more economical.
The interlocking bricks also ensures better stability and eliminating requirement of mortar layers. The different configurations of stretcher blocks, corner blocks, and half blocks provide flexibility in wall construction, accommodating junctions and creating staggered vertical joints.
The physical properties of interlocking blocks contribute to their durability and strength. Overall, interlocking bricks present a practical and efficient solution for construction projects, offering improved speed, convenience, and structural integrity.