What concrete densification is for and how it works

The concrete densification process aims to eliminate excess air, water and voids in the newly poured concrete. This procedure ensures a denser, more homogeneous material with greater mechanical resistance, which guarantees the durability and safety of the structure being built.

Benefits of concrete compacting

Among the many benefits of compacting concrete is the improvement in the material's compressive strength. The presence of air bubbles or voids reduces the effective load-bearing area of the concrete, reducing its ability to withstand tension. Texts such as the Portland Cement Association's 'Design and Control of Concrete Mixtures' show that up to 5% of trapped air can reduce concrete strength by up to 30%. Eliminating these voids is essential to ensure that structures can withstand the loads for which they were designed. Compacting also contributes to a smoother, more uniform concrete surface. Well-finished surfaces are essential for architectural elements and for the effective application of coatings and paints, as well as improving the adhesion of coatings such as tiles and plaster.

Proper densification of concrete also influences its durability. Voids and excessive porosity allow the infiltration of water and aggressive agents such as chlorides and sulphates, which can accelerate the process of corrosion of the reinforcements and the deterioration of the concrete. This is critical in structures exposed to severe environmental conditions or underwater, such as bridges and foundations. This is why densification not only improves durability, but also resistance to the formation of efflorescence and stains on the surface, as well as extending the useful life of structures, reducing the need for maintenance and repairs.

Types of concrete compacting

Manual densification

Used on small construction sites or in places that are difficult to access, where the use of mechanical equipment is impractical. Hand tools such as sticks or tamping irons are used. Although it is a simple method, it requires skill to be effective and to avoid segregation of the concrete components.

Vibration densification

Widely used due to its effectiveness, it consists of the use of vibrating equipment, such as immersion or needle vibrators, and surface vibrators. The vibration induced in fresh concrete causes the aggregate particles to settle better, expelling trapped air and increasing the density of the material.

Centrifugal densification

Mainly used in the manufacture of precast parts such as concrete pipes and posts. The material is placed in molds that rotate rapidly. The centrifugal force pushes the concrete against the walls of the mold, ensuring high density and resistance.

Vibrocompression densification

This method combines vibration with simultaneous compression and is normally used in the production of concrete blocks and precast parts. The mold is subjected to vibrations while a press applies pressure, resulting in parts with high compactness and mechanical strength.

Studies and technical standards, such as those of the American Concrete Institute (ACI) and the Brazilian Association of Technical Standards (ABNT), provide detailed guidelines on densification procedures. In all its projects, Stecla Engenharia works with the most appropriate techniques, always aiming to achieve the best quality while respecting deadlines and costs.