Properties and technology of preparation of large-pore expanded clay concrete

Welcome to "All about Concrete," where we delve into the diverse and intriguing world of concrete. This article explores the characteristics and technology of large-pore expanded clay concrete, a specialty kind of concrete with special advantages for building.

The excellent thermal insulation properties and lightweight nature of large-pore expanded clay concrete are well-known. Expanded clay aggregates are lightweight ceramic pellets used in its manufacturing. Because of their porosity, these pellets allow air to enter the concrete mixture. This property lowers the concrete’s overall weight while increasing its thermal efficiency, which qualifies it for use as insulation as well as structural applications.

Large-pore expanded clay concrete is made using a particular mix design that combines these lightweight aggregates with water, cement, and occasionally additional additives. The appropriate strength, durability, and thermal performance are obtained by carefully balancing the proportions of these components. The expanded clay aggregates are dispersed uniformly during mixing to guarantee consistency in the finished product.

The capacity of large-pore expanded clay concrete to offer structural strength at a lower weight than conventional concrete is one of its main benefits. This makes it especially helpful in applications like precast elements, high-rise buildings, and bridge decks where weight savings are essential. Its thermal insulation qualities also lower heating and cooling expenses and improve building energy efficiency.

Large-pore expanded clay concrete is used in construction for a number of applications, such as lightweight fill materials and insulating concrete panels. For architects and engineers looking to achieve both structural integrity and energy efficiency in their designs, its performance and versatility make it a top option.

This post will go into great depth about the production process of large-pore expanded clay concrete, its unique characteristics that make it stand out from other forms of concrete, and real-world uses for which it works exceptionally well. Come along as we explore the cutting-edge technology underlying this specialty concrete and how it has influenced contemporary building techniques.

Properties of large-pore concrete

Because there isn’t any sand in the mixture, concrete becomes much more porous and voids start to appear between the granules. As a result, this kind of expanded clay concrete gains the best qualities:

• Vapor permeability coefficient from 0.13 to 0.2 mg / m * h * Pa (for comparison, for reinforced concrete structures this figure does not exceed 0.03 mg / m * h * Pa).
• Water permeability – no more than 1.5%. None of the other lightweight concretes can boast such indicators either. Therefore, large-pore expanded clay concrete is best suited for the construction of walls and partitions in baths, saunas, vegetable stores and other rooms with high humidity.
• Thanks to such low water permeability, the thermal conductivity of KPKB is not affected by humidity conditions.
• The air permeability resistance of the material is 6-10 m2 * h * Pa / kg (for comparison, for ordinary concrete this figure is about 20,000 m2 * h * Pa / kg). Due to such properties, large-pore expanded clay concrete is rightfully considered the most “breathing” material.
• Products made of lightweight concrete have good heat and sound insulation properties.
• The consumption of KPKB is significantly lower than that of ordinary concrete, due to which the cost of constructing objects from this material is significantly cheaper.

When discussing the drawbacks of the content, it is important to emphasize the following drawbacks:

• Despite its strength, encapsulated expanded clay concrete is a rather fragile material. In terms of compressive strength, ordinary expanded clay concrete significantly exceeds KPKB. Therefore, large-pore expanded clay concrete is used only in frameless construction of low-rise buildings.
• Due to low water absorption and larger granule size, when laying and plastering the material, it is necessary to use special additives – modifiers that increase adhesion.
• Heavy shelves and other equipment cannot be hung on the KPKB structure without special fixing fasteners.
• To make this type of expanded clay concrete mix, you need special equipment.

KPKB is applied as a monolith or as blocks. Large-pore expanded clay concrete can be independently produced right on the construction site, if that is what is desired.

Preparation of KPKB

Encapsulated building material is a challenging material to make, much like other lightweight concretes on porous fillers. Since each ingredient is chosen experimentally, there isn’t a set recipe for making KPKB, but there are a few basic suggestions that can assist you in determining the ideal ratio fast:

• expanded clay granules with a fraction of 10-20 cm (bulk density of no more than 350 kg / m 3 ) – 1 kg;
• portland cement (grade not lower than M400) – 120 kg;
• PVA glue and liquid glass – 4 l each;
• liquid soap – 2 l;
• water.

Here, soap, PVA, and liquid glass serve as a less expensive equivalent of plasticizers. It is advised to use specialist plasticizing additives to improve the strength, plasticity, and bonding of the material if you want a higher-quality mixture. Although butadiene-styrene copolymer and styrene-acrylic ester are also suitable as additives, private construction seldom uses these materials.

If the final product is of high quality, it is advised to make a test block of expanded clay concrete and record the component proportions to avoid making mistakes with the cement amount. A good material is one that fractures along the granules rather than in between them.

Practical! The components’ ratio may vary during subsequent mixing, but no more than 1.5%.

The solution should not be mixed in a traditional concrete mixer because gravity causes the mass to move in such a mixer. Since encapsulated expanded clay concrete is lightweight, investing in a mixer-capsulator or a concrete mixer with specialty blades is preferable.

The building mixture’s constituent parts are put into the mixer in the following order:

1. Fill with expanded clay.
2. Pour in water (2/3) with additives dissolved in it.
3. Mix the components.
4. Pour in cement.
5. Start the mixer and gradually pour in the remaining water while mixing.

The amount of water used is determined by how dry the expanded clay granules are.

Recommendations for building walls from KPKB

When working with encapsulated material, remember the following advice:

• Use fiberglass ties to connect parts of the reinforcing mesh. Metal wire will quickly oxidize, causing corrosion.
• The internal and external plaster layers must be at least 150 mm.
• When carrying out facing work, pay attention to the fact that the resistance to vapor movement of the internal cladding must be greater than that of the external finish. If this condition is not met, there is a risk that water will accumulate in the walls.
• As a non -removable formwork, you can use brick masonry (in half a brick), and wooden frames. Wood will not rot or decay inside the walls.

• For working with encapsulated expanded clay concrete, you can use a compactor vibrator, but not more than 15 seconds. Otherwise, the cement mortar will flow off the filler granules.

Large-pore expanded clay concrete combines outstanding thermal insulation and structural stability with lightweight qualities to provide a flexible solution for a range of construction applications. Its distinct composition—which keeps its compressive strength high while using expanded clay aggregates—contributes to its low density. This makes it perfect for uses like high-rise buildings, bridges, and infrastructure projects where it is advantageous to reduce the overall structural weight.

Strict control over the mixing process and deliberate raw material selection are key components of the technology used to prepare large-pore expanded clay concrete. Essential elements are expanded clay aggregates, which are selected for their low weight and resistance to temperature changes. Admixtures may be added to improve workability and durability, and cement, sand, and water are combined in exact proportions to guarantee correct bonding and setting.

The thermal performance of large-pore expanded clay concrete is one of its main benefits. Building heating and cooling expenses can be decreased by using effective insulation made possible by the expanded clay’s porous structure. This energy-efficient feature not only increases sustainability but also raises indoor comfort levels by sustaining consistent temperatures all year long.

To sum up, large-pore expanded clay concrete is a unique combination of strength, lightweight qualities, and thermal insulation that makes it an effective and sustainable building material. The increasing use of it in different construction projects is a result of its performance advantages and environmental benefits. Further developments in the manufacture and use of expanded clay concrete offer even more efficiency and adaptability in contemporary building methods as technology develops.

This article from "All about Concrete" examines the special qualities and methods of preparation of expanded clay concrete with large pores. This special version of concrete has outstanding thermal insulation and lightweight qualities, which makes it perfect for building projects where structural integrity and energy efficiency are crucial. We explore expanded clay aggregate composition, how they improve the performance of concrete, and the specific techniques for mixing and placing this kind of concrete. Readers will acquire knowledge about the advantages and real-world uses of large-pore expanded clay concrete in contemporary building techniques by comprehending these facets.

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