precast concrete molds for sale

What are concrete interlocking blocks?

Concrete interlocking blocks are large lego-like bricks with studs on the bottom and recesses on the top. Because of these studs and recesses, constructions built with stacked interlocking blocks have  amazing strenght. This principle the build of mortarless walls (dry-stacked), no filler or bonding agent needed. The blocks are designed to function as a standalone item like a barrier, or can be used to build an integrated construction. Several blocks in various shapes and sizes may be needed to create a complete building structure. The blocks can be used in dozens of applications and industries.

Who produces concrete interlocking blocks?

Some concrete production plants have made the production of interlocking blocks their corebusiness, others make them as a side business to the production of other concrete products or create the blocks because they seek a useful application for concrete that would otherwise be disposed.

Material recycling facilities (MRF) that use secondary materials for the production of concrete also make the stackable concrete blocks. The use of secondary material prevents the need for virgin (primary) materials, which creates an interesting opportunity for recycling plants to produce valuable products from waste.

At construction sites, concrete blocks are produced with the residues left over from pouring floors or walls.

There are also specialized companies who deliver specials that require different shapes and small amounts are required. Wholesalers selling bulk materials such as sand and gravel add the concrete interlocking blocks to their delivery program to provide their customers related products for project solutions.

Moulds for the production of interlocking blocks are by both consumers and producers of concrete products. Various sizes and forms are available.

Where are concrete interlocking blocks made for?

Interlocking concrete blocks are predominantly used to build:

• Blast walls
• Boundary walls
• Wall structures
• Counter weights
• Crash protection blocks
• Fire break walls
• Flood protection
• Permanent traffic management
• Temporary traffic management
• Push walls
• Retaining walls
• Property barriers
• Security fences
• Silage pits
• Storage bays

Is it possible to use different shapes of concrete interlocking blocks?

There are many benefits to using different shapes of interlocking blocks. When building a wall, normally a running bond is used to give the wall stenght and, half blocks are needed to finish it off. Rooftops and half roof tops are used to prevent leakage at the top of walls. Slope blocks may be used for product storage areas where the slope of the block follows the natural slope of sand. This shape will also prevent the building of material on top of blocks.

Blocks with fork lift inserts can be easily moved and stacked with a forklift. Stair blockscan be used to move between different levels which may be useful, for instance in truck or loader washing areas or load inspection areas.
Flat tops are used when a flat surface is desired for easy cleaning. Foot blocks are used to create a stronger basis for a wall and round blocks can be used for curved walls.

A modular design for the steel moulds used to pour the concrete blocks is essential to avoid high purchase costs. Fortunately a reconfigurable thought-out mould design is available for purchase.

Which block sizes are available?

The majority of mould manufacturers offer products to produce concrete interlocking blocks of 160x80x80 cm or 160x80x40 cm.

The moulds from Block Moulds are modularly constructed. A total of 127 block types can be produced with the basic block mould and the inserts.

Big stud’s block sizes:
• Length 40/80/120/160cm
• Width 40/80cm
• Height 40/80cm.

Small Stud’s block sizes:
• Length 30/60/90/120/150/180/210/240cm
• Width 30/60cm
• Height 30/60cm.

All basic blocks can be modified by using the basic mould and following inserts:
• Divider plate
• Forklift
• Slope block
• Stairs
• Flat top
• Flat top + divider plate
• Roof top
• Roof top + divider plate

How heigh can concrete interlocking blocks be stacked?

The maximum stacking height depends on the width of the block.

On a stable and horizontal surface, blocks can be stacked to the following heights:

• Width 30cm -> 2.3m high
• Width 40cm -> 3.3m high
• Width 60cm -> 6.1m high
• Width 80cm -> 9.1m high
• Width 120cm* SN -> 6.6m high
• Width 120cm* BN -> 9.9m high
* Footblock used as a basis

Depending on the type of load and its surface angle you can stack material against a stacked wall:

Width Material Surface angle Density Height
60cm Sand 30o 1500kg/m3 1.8m
60cm Waste 35o 1500kg/m3 2m
60cm Salt 40o 1200kg/m3 2m
60cm Wood 35o 650kg/m3 2.8m
60cm Soil 45o 500kg/m3 3m
80cm Sand 30o 1500kg/m3 2.4m
80cm Waste 35o 1500kg/m3 2.4m
80cm Salt 40o 1200kg/m3 2.4m
80cm Wood 35o 650kg/m3 4m
80cm Soil 45o 500kg/m3 4.8m

How do you lift a concrete interlocking block?

A block cast with a mould with forklift inserts can be lifted with a forklift.
Concrete interlocking blocks can also be lifted with a (stone) clamp connected to a forklift, wheel loader, crane or other type of lifting device.

Can concrete interlocking blocks be used to build a break wall?

Tests have shown that 800mm concrete interlocking blocks have a fire retention time of 4 hours.
This is long compared to other  structural measurements for fire retention.
Considering their price and their retention time, concrete interlocking blocks are a good choice to build fire retaining walls. For this application please consult a construction specialist.

How often can you reuse concrete interlocking blocks?

Concrete interlocking blocks can normally be used an infinite number of times. The impact of equipment and other external forces or replacing the blocks with blunt force can cause them to wear.
In normal conditions, however, they can easily last over 25 years.

How do you rotate concrete interlocking blocks?

Concrete interlocking blocks are cast on their side. To be able to stack them they need to be rotated 90 degrees, and there are several ways to do that.

The most basic method is to place the block on two wooden beams to create some space underneath. Place some old car tires (or other soft landing item) on the ground in the direction of rotation (indented side). Put some rubber on the tips of the forklift forks and slide them under the block from the side with the protruding studs.

When lifting the forklift forks the block is turned over in a controlled way and will land on the old rubber tyres. Rotation should only be performed by experienced employees taking all the necessary safety precautions. No one should be near the block when it is being rotated. Keep in mind that the block is heavy and will make quite the impact when rotated.

The best way to rotate the blocks is by using a block rotator. The block is placed in the machine, after which the rotating system is released. When the block is rotated, it can be removed to prepare the machine for the next block.

What is the best method to keep concrete from sticking to the mould?

Moulds for interlocking concrete blocks are mainly fabricated from carbon steel. The walls of the mould need to be sprayed with sufficient release agent, such as oil.

A well-sprayed mould is the best precaution to remove the parts of the mould without any problems.

Time is of the essence; the mould release agent should be applied just before the concrete is poured into the mould. It is important to use a non-reactive, high grade mould oil with the right viscosity.

It is advised to spray the outside of the mould and floor surface inside the mould as well. This avoids residual concrete sticking to the mould after pouring and to ensure a smooth top surface of the concrete block.

How are concrete interlocking blocks made?

Concrete interlocking blocks are made out of high-grade concrete or concrete made from recycled waste aggregates. The concrete block is formed by pouring ready-mixed concrete into a steel mould. Our instruction for the use of steel moulds  shows how to pour the concrete step by step.

The basic, rectangular shaped block, is made with the basic block mould. By using compatible insert elements that can be mounted into the mould, other block shapes can be created. The basic block mould combined with our range of inserts form the solution to create various shapes. A modular mould construction allows users to easily produce various forms and sizes without large investments.

Why are concrete interlocking blocks made?

Concrete interlocking blocks satisfy demand for:

•  low cost structures
•  temporary storage structures
•  temporary or permanent barriers
•  walls that can be reconfigured or relocatedfor a business that needs an adaptable construction
• cheap and solid flood protection
• modifiable structures
• low cost and maximum performance
• lowest storage cost per m3
• structures capable of withstanding high forces from heavy forklifts or wheel loaders
• builds that require alsmost no permits
• applications to produce valuable products while recycling raw materials
• valuable solutions to use concrete leftovers at construction sites

What are the benefits of using concrete interlocking blocks?

Concrete interlocking blocks can used in temporary or permanent cost-friendly constructions. They allow the user to make quick and easy design changes. The weight of the concrete and the fact that the blocks can be stacked without the use of mortar allows the user to quickly build solid solutions. The design of the blocks creates endless possibilities to build solutions in project situations that require flexible layouts.

What type of stud connections do concrete interlocking blocks have?

Market leaders in the production of interlocking concrete blocks designed trapezium shaped nock connections, which is also known as “studs”. Stud exists in two different sizes BN and SN:
• BN is the abbreviation for Big Nock (Big studs)
• SN is the abbreviation for Small Nock (Small studs)

Big nocks can be found on the block sizes:
• Length 40/80/120/160cm
• Width 40/80cm
• Height 40/80cm

Small Nocks can be found on block sizes:
• Length 30/60/90/120/150/180/210/240cm
• Width 30/60cm
• Height 30/60cm

Several suppliers have their own stud sizes but that often makes their blocks incompatible with our standardized stud sizes. If you would like more detailed information on the pattern, height and circumferences of the studs, you can always contact the producer of the steel moulds.

Block Moulds produces the stud sizes that are most prevalent in the market of interlocking blocks. We also offer custom-made stud configurations if required, like round studs or studs with different dimensions. Buying a complete new moulds is not necessary with our modular mould design, because various stud designs can be produced by changing only the bottom and top plate.

If you have concrete interlocking blocks with different stud types, a mould can be assembled to produce transition blocks. An optimal cost-effective way to be able to use various batches of interlocking blocks available on the secondary market.

What is the weight of concrete interlocking block?

Due to their size differences all basic blocks have different weights.
The table below shows the weight of each basic block.

Interlocking concrete blocks, Big Nock (big studs) type:

Width 40 cm 40 cm 80 cm 80 cm
Height 40 cm 80 cm 40 cm 80 cm
Length 40 cm 154 kg 307 kg 307 kg 614 kg
80 cm 307 kg 614 kg 614 kg 1229 kg
120 cm 461 kg 922 kg 922 kg 1843 kg
160 cm 614 kg 1229 kg 1229 kg 2458 kg


Interlocking concrete blocks, Small Nock (small studs) type:

Width 30 cm 30 cm 60 cm 60 cm
Height 30 cm 60 cm 30 cm 60 cm
Length 30 cm 65 kg 130 kg 130 kg 259 kg
60 cm 130 kg 259 kg 259 kg 518 kg
90 cm 194 kg 389 kg 389 kg 778 kg
120 cm 259 kg 518 kg 518 kg 1037 kg
150 cm 324 kg 648 kg 648 kg 1296 kg
180 cm 389 kg 778 kg 778 kg 1555 kg
210 cm 454 kg 907 kg 907 kg 1814 kg
240 cm 518 kg 1037 kg 1037 kg 2074 kg

* Weights are based on a concrete density of 2.400kg/m3.

Can bottom ash (IBA) be used in concrete interlocking blocks?

According to the rules of the Green Deal IBA may be used in bound form. Therefore usage in concrete interlocking blocks is allowed. IBA must be non-reactive before it can be used in concrete interlocking blocks. Otherwise the blocks might “grow” and fall apart.

Are concrete interlocking blocks similar to LEGO blocks?

Concrete interlocking blocks are stacked similarly to the way LEGO blocks are stacked. The interlocking studs fit into recesses and hold the block into place as an integrated piece of a wall.
Concrete interlocking blocks are often popularly called LEGO blocks, although they are not connected to the LEGO brand. The term is only used to illustrate the way in which the blocks are stacked, although in detail, the blocks are not identical to LEGO blocks at all.

Is cement or mortar needed to connect concrete interlocking blocks?

Due to the top and bottom structure of interlocking blocks no additives or binding material are needed to build with them. To fixate them, they just need to be stacked in such a way that the protruding studs of the lower block fit in the indents of the upper block.

A running bond will make the walls extra strong. Due to the shape off the studs the blocks can only be removed when they are shifted or lifted. The weight of the blocks prevents this from happening.

Can concrete interlocking blocks only be purchased, or can you also rent them?

Concrete interlocking blocks can be rented, which is common for event-related solutions like anti-terror barriers, roadblocks, or anchoring tents.

Due to their relatively low production costs, most blocks are purchased.
If the blocks are not needed anymore they can be easily sold because they keep their value. There is a large market for second-hand interlocking concrete blocks.

How to position interlocking blocks?

For the best result and optimal strength, interlocking blocks need to be placed using a running bond. This method will ensure a solid connection with the rest of the wall. In this way, each individual block contribute to the strength of the structure. This is very useful if walls have to resist external forces, like in push wall  applications.