Product Role: Sprayable UHPC and shotcrete grout solutions enable the placement of ultra-high performance concrete in complex or hard-to-access areas by means of spraying (shotcreting) rather than traditional pouring. The role of these products is to provide the strength and durability advantages of UHPC in a form that can be applied overhead or on vertical/irregular surfaces without formwork. This is particularly valuable for reinforcing tunnel linings, repairing corroded concrete in parking garages or marine pylons, and strengthening structures like domes or shafts from the inside. The sprayable UHPC binds to existing substrates and forms a high-strength protective layer or structural shell. By eliminating the need for molds, these solutions dramatically speed up construction and repair timelines and make it feasible to upgrade structures that would otherwise be impractical to cast in place.

Application Challenges: When working in tunnels, mines, or retrofit projects inside existing structures, conventional concrete placement faces challenges such as limited working space, complex geometries, and the need for quick application to minimize downtime. Traditional shotcrete (using normal concrete) is commonly used, but it has limitations: standard shotcrete may not achieve the high strengths or low permeability needed for long-term durability, can exhibit significant rebound (material waste falling off the wall), and often shrinks during curing leading to cracks or poor bonding. Additionally, achieving rapid strength gain is a challenge when trying to reopen facilities quickly (for example, tunnel sections or industrial plants). ZRETE’s range of UHPC shotcrete grouts addresses these issues. The mixes are formulated to have high build thickness per pass and low rebound, meaning they adhere well to surfaces (even overhead) and more of the material ends up on the structure rather than on the floor. The inclusion of fine powders and admixtures in UHPC ensures a very cohesive mix that can incorporate steel fibers uniformly, giving it excellent hanging ability on vertical surfaces without sagging. Another challenge is controlling shrinkage and curing in a sprayed application – the “No-Shrink” UHPC grout variant is specifically designed to remain volume-stable, preventing cracking or debonding as it sets. For projects in cold weather or on a fast schedule, the “Early-Strength” UHPC grout variant gains significant strength within the first 24 hours (over 20 MPa in one day), allowing for quicker load application or successive construction steps. Each of these sprayable products also must bond strongly to the existing concrete or rock substrate; the ultra-fine particle matrix of UHPC, combined with its fiber content, provides exceptional adhesive qualities, often exceeding 3 MPa in pull-off strength on prepared concrete, which is well above typical requirements.

Product Performance: Once applied, sprayable UHPC and shotcrete grouts create a protective, structural layer that far outperforms ordinary shotcrete or repair mortars. The standard UHPC Shotcrete (Sprayable) mix achieves compressive strengths in the range of 100–150 MPa and flexural strength around 20 MPa, ensuring that even a thin sprayed layer (e.g., 30–50 mm) contributes significant structural reinforcement. These materials are also designed to be highly durable: they are virtually waterproof and chloride-proof, safeguarding the substrate from corrosion and freeze-thaw damage. For instance, a sprayed UHPC lining in a tunnel not only adds strength to the lining but also prevents water ingress and deterioration of the original concrete behind it. The CBGM-SHOTCRETE-UHPC120 Grout is a high-performance grout with around 120 MPa compressive strength, tailored for general infrastructure enhancement – it strikes a balance of workability and strength, making it suitable for bridges, culverts, and pier repairs where a reliably dense, strong overlay or section repair is needed via spraying. The Early-Strength Grout variant demonstrates fast setting and rapid strength development, which is a game-changer for emergency repairs or winter construction; structures treated with this grout can reach structural capacity quickly, minimizing closure times. It also maintains high bonding and low rebound, which are critical for effective use. The No-Shrink Grout variant offers assurance that once the UHPC is in place and cured, it won’t undergo significant shrinkage that could lead to micro-cracking or pull away from the substrate – a crucial attribute for precision grouting around anchors or in jacketing applications. In field conditions, these sprayable UHPC grouts have proven capable of adhering even to complex surfaces (like ribbed or rough substrates) and creating a monolithic, joint-free repair. The resulting rehabilitated structure benefits from UHPC’s hallmark longevity: resistance to abrasion (important in, say, a spillway or industrial silo lining), immunity to chemical attack and corrosion (ideal for maritime or wastewater environments), and an overall increase in load-bearing performance. Ultimately, sprayable UHPC & shotcrete grouts allow engineers to impart new life and strength to structures with the convenience of shotcrete placement, thus uniting ease of application with the unparalleled performance of UHPC.

Product Matrix:
UHPC Shotcrete (Sprayable)  CBGM-SHOTCRETE-UHPC120 Grout  CBGM-SHOTCRETE Early-Strength Grout
CBGM-SHOTCRETE No-Shrink Grout