Spray concrete, also known as shotcrete, is a method of applying concrete by spraying a mixture of cement, aggregate, and water onto a surface. This technique is commonly used in structural applications such as tunnels, swimming pools, and retaining walls, as well as for repair works to restore or reinforce existing structures. It is also effective for slope stabilization to prevent erosion and landslides. There are two main types of spray concrete: the wet mix, where all ingredients are mixed with water before being pumped through a hose and sprayed, and the dry mix, where dry ingredients are mixed and water is added at the nozzle during spraying. This method allows for faster application and greater versatility in various construction projects.