How to choose a high-quality expanded clay block: expert advice

Is a house made of expanded clay concrete good or bad? This is a ridiculous question that the customer often asks the builder. The answer is very simple: if the block is of high quality, then the house is good, and when the block falls apart in the hands, then the structure will be appropriate. So how do you define a solid block? Let's figure it out and imagine the situation that you came to look at the production. Pay attention to these details and they will save you from buying handicraft.

Equipment

A good block is made by vibrocompression and nothing else. Only the pressure of the hydraulic press creates the necessary adhesion, which allows the block to obtain sufficient heat engineering and strength characteristics. Self-made expanded clay block is usually made on a handicraft machine with a thin matrix and a small vibration motor below, and the role of the press is performed by a weighting agent, which several times with acceleration is lowered onto the block during vibration.

If you don't see any serious vibropress equipment in the shop where you want to buy a block, then don't expect good quality. In practice, the handicraft brand is no more than M15 - M25, when the manufacturer declares M50 (checked more than once in a construction laboratory). But the availability of good equipment does not guarantee quality - let's look further.

Materials

Ask the manufacturer to show the materials used and the finished blocks.

Expanded clay

Here you need to look first of all at expanded clay, which is divided into thermal and structural. Thermal (large) is not used for blocks and should not be on the territory of the workshop. Structural expanded clay should not exceed the size of a hazelnut. In production, two fractions are usually used: 5–10 mm for hollow blocks and 10–20 mm for solid blocks, but variations are possible. It is these fractions that are optimal for the production of a warm and durable expanded clay block.

Sand

It is worth paying attention to the sand used. To impart high strength, sand is added to the product and this is already a sand concrete block - less warm, but more durable. In such a block, up to 50% of sand, and the rest is expanded clay and cement. So the sand should be just building sand. To reduce costs, many manufacturers use fine sand dunes, whose characteristics are not suitable for creating durable structures.

Cement

And, of course, cement. The block should not crumble in hands and scatter into pieces when hitting the ground, corners, protruding irregularities and crumble when pressed with fingers should not break off from it. The product must be cement gray. Of course, the best option would be to take a couple of blocks to the laboratory and put them under the press - this will take time, but it will allow you to find out the strength of the product and its compliance with the declared characteristics.

According to statistics, when transporting a block in a dump, for M50 brand products, the percentage of breakage does not exceed 50 pieces per 1000, and for M75 brands no more than 30 pieces.

Concrete admixtures

Another nuance - an advanced manufacturer will use plasticizers that improve the characteristics of concrete products. The additives primarily neutralize many salts in the water, and also reduce their amount in the solution. Be sure to ask the seller about plasticizers.

Manufacturer tricks or construction waste

If there are extraneous materials on the territory of the workshop - small crushed stone, broken bricks, expanded clay aggregate, then there is a high probability that they are added to the block. Many manufacturers have adapted themselves and make crushers for processing scrap and thermal expanded clay into a fine fraction. Here you need to take into account one feature: crushed expanded clay loses its structural and thermal qualities. To put it simply - such a manufacturer, in order to save money, adds construction waste to the products, and this is a direct violation of technology.

Drying

Well, the last thing you need to pay attention to is the drying of the block. Ideally, it should be done by steaming; in other words, the block is kept in a hot, humid room for some time. After steaming, the products are placed on pallets and wrapped in stretch film: the full maturation period of concrete is 28 days and at least the first 7–10 days it should not lose moisture. The most dangerous thing for concrete at the time of hardening and maturation is wind or draft. If your location is a climate where there is no heat and high humidity, then the block may be outside. If you are a resident of the south, where there are many hot and sunny days, pay attention to how the products are dried and how they are packed.

Conclusion

Are you going to build from expanded clay block - pay attention to the specified details. The rule works here - there is no good and cheap at the same time: either the manufacturer works for quality, or not. For a chicken coop, you can take a cheaper one in the workshop from Uncle Zhora, but for housing it is better not to save.

How do you determine the quality of the expanded clay block? Write in the comments!

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