Lining Tunnel Used Concrete Spraying Machine

Pea Gravel Concrete Spraying Machine is a kind of mechanical equipment specially used for spraying gravel concrete (or concrete containing aggregate). It is widely used in support operations in underground engineering and civil engineering fields such as tunnels, subways, culverts, and slope protection.

Liquid accelerator for shotcrete is a chemical additive specially used in shotcrete construction. Shotcrete liquid accelerator is a liquid chemical agent that can significantly accelerate the setting and hardening process of shotcrete. It mainly reacts chemically with the cement component in concrete to quickly form a hardened structure, thereby improving the early strength and durability of shotcrete.

Concrete sprayers use high-pressure spraying technology to evenly apply concrete or mortar to target surfaces. They are widely used in tunnels, mines, slope reinforcement, building exteriors, and underground structures. Their core advantages include: Efficient construction: Spraying speeds far exceed those of traditional manual plastering, enabling a daily production capacity of hundreds of square meters.
Optimized quality: Reduced material waste (rebound rate as low as 5%-15%), high-density spray coatings, and improved impermeability by over 30%.
Adaptable to complex structures: Precisely conforming to curved and irregular surfaces (such as tunnel vaults) without the need for formwork support.

Accelerator dosage systems play a crucial role in optimizing shotcrete applications by ensuring precise control over concrete setting times and early strength development.

An additive dosing pump for a shotcrete machine is an essential component used to accurately meter and inject chemical additives (such as accelerators, retarders, plasticizers, or other admixtures) into the concrete mix during the shotcrete process. These additives can modify the setting time, workability, strength, or other characteristics of the shotcrete, making the pump a critical tool in tailoring the mix to the specific requirements of a project.

Compact shotcrete units are designed for small projects, local repairs or underground work with limited space.
Tunneling and underground engineering: used for tunnel lining, reinforcement and repair. Suitable for small tunnels or narrow areas.
Mining: tunnel support and repair in mines. Adapt to the complex terrain and limited space of mines.
Slope reinforcement and repair: used for shotcrete reinforcement of slopes to improve stability. Suitable for hard-to-reach slope areas.

The pneumatic dry mix gunite machine is a specialized construction tool designed for applying gunite (dry-mix shotcrete) using compressed air. It’s ideal for spraying concrete, mortar, or refractory materials onto surfaces, making it popular in tunneling, slope stabilization, pool construction, and repair work.

Pea stone shotcrete machines must be capable of spraying concrete containing pebbles (typically 5-20mm in size). Their pumping system must thoroughly mix the aggregate with cement slurry using high pressure (10-25 MPa), ensuring a shotcrete layer density of ≥95%.
Main application scenarios include:
Tunnel/mine support: Spraying pebbles to create a flexible support layer that adapts to geological deformation.
Slope reinforcement: Spraying fiber-reinforced concrete containing pebbles to improve shear strength.
Building exterior wall restoration: Spraying pebbles to create a finishing layer for enhanced durability.

Shotcrete machines with accelerator systems integrate advanced dosing technology with robust shotcrete equipment to deliver efficient and high-quality concrete spraying applications. They are essential for achieving rapid construction timelines and ensuring durable concrete structures in various construction and repair projects.

The accelerator metering pump is a key component in the shotcrete machine. It is responsible for accurately metering and delivering concrete accelerator. Accelerators can significantly increase the early strength of concrete, speed up construction, and improve the physical properties of concrete. Through precise metering and delivery, the accelerator metering pump ensures uniform distribution of concrete accelerator in shotcrete, thereby improving construction quality and efficiency.

An air-driven accelerator metering pump system for shotcrete is specifically designed to meter and inject chemical accelerators into the shotcrete mix during the spraying process. This system uses compressed air as the driving force, making it ideal for environments where electrical systems may not be suitable or where compressed air is already available, such as in tunnels, underground mines, and other hazardous work environments. The accelerator, a key additive in shotcrete, helps to reduce setting time and increase early strength development, which is critical in high-pressure environments.

Concrete shotcrete machine for underground is to transport the premixed dry materials (cement and aggregate) to the nozzle through a pneumatic conveying system, add water to the nozzle and then spray it out. This method is suitable for small-scale or temporary projects. In underground construction, shotcrete machines balance efficiency, safety, and adaptability. Their ability to rapidly apply durable concrete in challenging conditions makes them indispensable for modern tunneling and mining projects.

Compact concrete spraying machines for dry-shotcrete are specialized equipment used in the construction industry for applying dry-shotcrete mixtures. These machines are designed to efficiently spray concrete mixtures that have a low water-cement ratio (typically less than 0.25), making them suitable for a variety of applications where high-strength and durable concrete surfaces are required.

The main components of liquid shotcrete accelerators usually include alkaline substances (such as sodium hydroxide, potassium hydroxide, etc.), inorganic salts (such as aluminates, silicates, etc.) and some other organic or inorganic compounds as additives and regulators. These components are precisely proportioned and mixed during the preparation process to ensure that the performance of the accelerator is stable and meets the construction requirements.

There are many types of concrete shotcrete machines on sale. These devices are mainly used to continuously transport concrete along pipes and spray it onto the construction surface. They are widely used in shotcrete construction operations in underground projects, hydropower projects, shafts, tunnels, culverts and other fields.

The shotcrete system used by TBM (Tunnel Boring Machine) is a key equipment for timely support of surrounding rock in tunnel construction. Its core function is to mechanically spray concrete at high speed onto the excavation surface to form a support layer to stabilize the surrounding rock.

In shotcrete systems, the accelerator dosage pump plays a critical role in precisely metering and injecting accelerators into the concrete mix. The choice between dry and wet accelerator dosing depends on the specific requirements of the project and the properties of the accelerator used.

Small wet shotcrete machines are not directly used in fiber-reinforced dry shotcrete mixture projects. However, in situations where wet shotcrete is required, small wet shotcrete machines are still an efficient and reliable choice. For fiber-reinforced dry shotcrete mixture projects, it is necessary to select shotcrete equipment that is specifically suitable for dry shotcrete and has fiber reinforcement functions. In practical applications, the appropriate shotcrete equipment and process should be selected according to specific engineering requirements and material properties.

In dry shotcrete, liquid accelerators react with cement in the dry mix to quickly form a hardened structure. Since dry shotcrete is a mixture of dry mix and water and then sprayed onto the construction surface through a nozzle, the addition of liquid accelerators requires strict control of the mix ratio and mixing uniformity. In wet shotcrete, the mechanism of action of liquid accelerator is similar to that of dry shotcrete, but the construction method and mixing process are different. Wet shotcrete is to spray the pre-mixed wet mix onto the construction surface through a nozzle, so the addition and mixing process of liquid accelerator needs to be completed during the wet mix preparation stage.

Case analysis of dry and wet shotcrete machine for dam construction:
Dry and wet shotcrete machines have been widely used in many dam construction projects. For example, in the construction of a large hydropower station dam, a wet shotcrete machine was used for concrete spraying. By precisely controlling the spraying pressure and spraying angle, the flatness of the dam surface and the density of the concrete are ensured. At the same time, the efficient working performance of the wet shotcrete machine also greatly improves the construction efficiency and shortens the construction period.

Small concrete spraying system is a compact, efficient and easy-to-operate concrete spraying equipment suitable for various construction environments. By reasonably selecting and using the system, the construction efficiency and quality can be significantly improved, providing strong support for various concrete spraying operations.

Accelerators for shotcrete machine are often used to improve the working efficiency of shotcrete machines by accelerating the spraying speed of concrete so that the concrete can be covered and cured on the working surface more quickly. This can not only shorten the construction time, but also improve the construction quality and efficiency.

The pneumatic accelerated metering pump system usually consists of a pump body, a pneumatic servo device, a control system, etc. It uses compressed air as a power source and adjusts the stroke length (or flow rate) of the pump through a pneumatic servo device, thereby achieving accurate metering and accelerated delivery of liquids.

Concrete spraying machine is essential for lining tunnels, and the process is commonly known as shotcreting. This method is widely used in tunnel construction for ground support, stabilization, waterproofing, and structural reinforcement.