Paving stones and concrete precasts are essential elements of modern landscape architecture. Their quality and durability are directly related to the selection of aggregates and the technology used to prepare the concrete mix. Combining these two aspects correctly is crucial for achieving high technical and aesthetic standards.
Various types of aggregates, including gravel and crushed stone from rocks like basalt, granite, and limestone, are used in producing concrete paving stones. The choice of suitable aggregates depends on their availability and specific technological requirements.
The production of paving stones requires aggregates of specific grain sizes. The most commonly used fractions are:
Some technologies may require or allow the use of fractions 1-4 mm and 8-16 mm to complete the aggregate mix. Limiting the maximum grain size to 8 mm is important for both aesthetic and quality reasons. Too large grains tend to rise during compaction by vibropressing, which can negatively impact the aesthetic and uniformity of the compacted concrete's microstructure.
The quality of the aggregate is also crucial. It is recommended to use aggregates with suitable mechanical parameters, such as a low Los Angeles abrasion value (LA25) and water absorption not exceeding 1.6%. Aggregates should also be frost-resistant to ensure the durability of paving elements in harsh weather conditions.
Precise concrete mixing is a critical step in the production of paving stones, especially for multicolored paving slabs and stones. Traditionally, this process involved adding different pigments in batches, often leading to unwanted color mixing and inconsistency in the final product.
To address these challenges, manufacturers use modern planetary mixers, such as the SPM/SPMW models, which enable precise preparation of both dry and wet mixes. These innovative solutions allow optimal mixing of colors and consistency, significantly reducing waste.
The appropriate selection of aggregates and precise concrete mixing directly affect the quality of paving stones. Using well-chosen aggregates with the right grain size and high quality allows for the production of items with high compressive strength (at least 50 MPa) and great durability, even under conditions of heavy use with de-icing salts.
Producing high-quality paving stones requires careful selection of aggregates and precise concrete mixing. Aggregates should have the proper grain size and high quality, and the mixing process should be carried out using modern technologies. This approach ensures the production of aesthetic, durable, and strong products that meet the expectations of both customers and landscape architects.