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How to Produce High-Quality Shotcrete?

2025-09-12

Producing fiber-reinforced concrete often presents challenges for concrete manufacturers—particularly in shotcrete production. While fiber-reinforced concrete is primarily used in specialized projects, its production requires factories to have appropriate equipment, including a reliable concrete mixer designed to handle fibrous mixtures. Below, we outline key considerations for producing high-quality fiber-reinforced concrete specifically for shotcrete applications.


Raw Materials and Mixture Design of Fiber-Reinforced Concrete


Fibers are essential for reinforcing concrete, helping prevent cracking in hardened concrete and enhancing its fire resistance. The most commonly used fibers include steel, plastic, glass, and polypropylene. When incorporating these fibers, the concrete mixer plays a critical role in ensuring uniform distribution—poor mixing can lead to fiber clumping, which undermines structural integrity.


For shotcrete production, high-quality materials with consistent composition are non-negotiable. The concrete mixer must process aggregates with a maximum size of 8-10 mm, as larger particles risk clogging the spray nozzle during application.


Cement dosage in fiber-reinforced concrete is relatively high, sometimes reaching 500 kg/m³. To reduce cement usage, supplementary binders like microsilica or limestone powder are often added, and the concrete mixer must thoroughly blend these materials to maintain homogeneity.


A water-cement ratio (w/c) below 0.45 is standard, making workability challenging without chemical admixtures. Here, the concrete mixer’s efficiency becomes vital: it must disperse plasticizers or superplasticizers evenly to ensure the mixture remains pumpable and sprayable. Without proper mixing, even the best admixtures cannot compensate for poor material distribution.


Additionally, accelerators are introduced in the shotcrete machine to speed up setting and hardening, improving adhesion to vertical and overhead surfaces. However, pre-mixing preparations in the concrete mixer—such as controlling slump and fiber dispersion—lay the foundation for successful accelerator integration and overall shotcrete performance.

concrete mixer

What should concrete plants consider?

Concrete plants must prioritize the concrete mixer for fiber-reinforced shotcrete. Choose a mixer with specialized agitators to prevent fiber clumping. Maintain and calibrate it for uniform blending of fibers, cement, and additives. Sync mixer output with shotcrete machines to avoid segregation, ensuring consistent quality from mixing to application. The concrete mixer is key to reliable production.

Conclusion

High-quality fiber-reinforced shotcrete needs both proper raw materials/mixture design (consistent fibers, 8-10mm aggregates, low water-cement ratio, plus admixtures) and plant considerations. Plants must use specialized concrete mixers (to avoid fiber clumping), maintain them well, and sync mixer output with shotcrete machines—these ensure the mixture’s quality and performance.