What is the difference between shotcrete and sprayed concrete? "Shotcrete" and "sprayed concrete" are terms often used interchangeably, but they technically refer to different processes. Here's a breakdown of the differences:

　　1. Process Type

　　- Shotcrete: This typically refers to concrete （or mortar） that is applied using high pressure through a nozzle, allowing it to be "shot" onto surfaces. It generally refers to both wet-mix and dry-mix methods. The term "shotcrete" is most commonly used in North America.

　　- Sprayed Concrete: In many parts of the world, particularly Europe, "sprayed concrete" is the preferred term, and it can also refer to both the wet and dry application methods.

　　2. Application Methods

　　There are two main methods of application: wet-mix and dry-mix.

　　- Wet-Mix Process: In this method, the concrete mixture is prepared with water before being pumped through the hose and sprayed. The wet-mix process allows for better control of water content and is generally used for larger jobs.

　　- Dry-Mix Process: Here, dry ingredients are mixed and then pushed through the hose with compressed air. Water is added at the nozzle, which allows for more immediate adjustments. This method is typically used for smaller jobs or repairs.

　　Both terms—shotcrete and sprayed concrete—can refer to either the wet or dry mix, but "shotcrete" is more commonly associated with the wet-mix process in North America.

　　3. Use Cases and Regional Preferences

　　- Shotcrete: Frequently used for structural applications like tunnels, retaining walls, swimming pools, and domes, especially in North America.

　　- Sprayed Concrete: More commonly used in Europe and other regions, with similar applications but a preference for projects requiring high-strength material and quick setting times.

　　Key Differences

　　- Method of Mixing: Shotcrete typically emphasizes the high-pressure mixing just prior to application.

　　- Speed of Application: Shotcrete can achieve higher placement rates due to its kinetic energy imparted during the spraying process.

　　- Mix Type: Sprayed concrete can encompass both wet- and dry-mix methods, while shotcrete traditionally refers specifically to the dry-mix process, though modern usage may include wet-mix techniques as well.

　　In summary, while "shotcrete" and "sprayed concrete" are often used interchangeably, the difference largely depends on regional terminology, preferred application methods, and sometimes the specific mix used.