Comparison · 6 min
What is foam concrete, and how does it differ from Redblok?
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Foam concrete is a lightweight concrete without coarse aggregate, made by adding preformed foam to a cement paste. It can be poured on site, or cast in moulds and cut into blocks. Redblok is a lightweight concrete block made by this method. The difference lies in production: a separate mix developed by TÜRKBETON for each density class, factory cutting and a record kept for every batch.
What is foam concrete?
Foam concrete is a paste of cement, fine material, water and admixtures. Preformed foam, made in a separate machine, is added to this paste. The foam leaves a great many small air pores inside. There is no coarse aggregate. The material gets its lightness from the air it holds.
The amount of foam sets the density. Dry density is usually chosen between 300 and 1,000 kg/m³, depending on the project. Normal concrete weighs about 2,400 kg/m³. Foam concrete does not go into an autoclave; it gains strength as the cement hardens.
Where is foam concrete used?
Foam concrete is used in two ways. Fresh, it can be poured on site: roof falls, light fill over slabs, and void or trench fill are examples. Cast in moulds and cut, it becomes a wall block for non-loadbearing internal partitions and infill walls within a frame.
TÜRKBETON makes blocks only. We do not pour on site, lay screed or place fill. We do not make autoclaved aerated concrete (AAC) either.
How is Redblok made?
Redblok is a non-autoclaved lightweight concrete with closed air pores, made by the foam concrete (CLC) method. We batch the paste by weight in the factory and add preformed foam under control. Fresh density is measured on every mix. We then cast the mix into block moulds, cure it, cut it to standard size on the cutting line and palletise it.
We developed a separate mix for each density class. Admixtures and ratios are proprietary. Dry density, compressive strength and water absorption are recorded for every batch, and we can add these records to your project file. Our Şanlıurfa Birecik factory is in production; our Erzurum OIZ factory is being installed.
What is the weak point of non-autoclaved concrete?
To be frank: non-autoclaved concrete usually shows lower strength and higher drying shrinkage than autoclaved aerated concrete of the same density. That is the starting point for an ordinary foam concrete block and for Redblok alike.
We developed the Redblok mix around that point. We keep the water content low and add fibres against shrinkage cracking. Blocks are covered for the first day and then cured under control for seven days. We show the result with values measured on every batch, not with claims. For now the density-class values are design targets, confirmed by trial mixes and laboratory tests.
What should you check when buying blocks?
Whichever block you choose, ask for these in writing: density class and target dry density, a compressive strength test report, the water absorption value, the batch record and the dimensional deviation.
Cellular lightweight concrete lies outside the scope of EN 206, so its performance is defined by the project specification and laboratory testing. AAC blocks are defined by the EN 771-4 product standard. Compare blocks on these documents. The table below puts the two blocks side by side on the same criteria.
Redblok and ordinary foam concrete blocks
Both are non-autoclaved lightweight concrete. The difference lies in how the mix is set up and how production is measured. The right-hand column shows what to ask when you buy a block.
| Criterion | Redblok lightweight concrete block | Ordinary foam concrete block |
|---|---|---|
| Where it is made | In a factory: mould casting, curing, a cutting line and palletising. Our Şanlıurfa Birecik plant is in production. | Depends on the producer. Some blocks are moulded outdoors or on site. Ask where they are made and how they are cured. |
| Mix design | A separate mix developed by TÜRKBETON for each density class. Admixtures and ratios are proprietary. | Even at the same density, results depend on the mix. Ask whether the mix is fixed per class. |
| Density class declaration | The class code and target dry density are stated (500–800 kg/m³ design band for blocks). | Check that a class and target dry density are stated in writing. |
| Batch records and tests | Fresh density is measured on every mix. Dry density, compressive strength and water absorption are recorded for every batch and can be added to the project file. | Ask for batch records and a test report: dry density, compressive strength, water absorption. |
| Dimensions | Cut to standard size on the cutting line. Size and squareness are checked for every batch after cutting. | Size depends on the mould and the cut. Measure a few blocks to check the deviation. |
| Hardening | No autoclave. Covered for the first day, then seven days of controlled curing. | No autoclave. Curing time and conditions vary by producer. |
| Strength and thermal conductivity | Design target per class; confirmed by laboratory testing. | Ask for the declared value and the test used to measure it. |
| Use | Non-loadbearing internal partitions and infill walls within a frame. | Non-loadbearing walls. The block is not a loadbearing wall material. |
This table is not a claim of superiority. The known weak point of non-autoclaved concrete is lower strength and higher drying shrinkage than an autoclaved product of the same density. We developed the Redblok mix around that point and measure every batch. Compare blocks on their test reports.
Frequently asked questions
- Is foam concrete the same as lightweight concrete?
- No. Lightweight concrete is a wider family. Pumice-aggregate concrete, autoclaved aerated concrete and foam concrete all belong to it. Redblok is a lightweight concrete block made by the foam concrete method.
- Is Redblok a foam concrete block?
- By material class, yes: Redblok is a non-autoclaved lightweight concrete with closed air pores. You see the difference in production, not in the name: a separate mix for each density class, factory cutting and a record for every batch.
- Can Redblok be used in loadbearing walls?
- Redblok is made for non-loadbearing partitions and infill walls; the reinforced concrete or steel frame carries floor and roof loads. Whether any other block may be used in a loadbearing wall is decided by the structural design and the responsible engineer.
- Does TÜRKBETON pour foam concrete on site?
- No. We only make Redblok lightweight concrete blocks, cut and palletised in the factory. We do not do poured fill, screed or roof falls.
Tell us about your project and let our engineers assess it.
Start with a wall quantity, a block size, a project drawing or simply a requirement brief. We respond within 24 hours.