Study into “sprayability” of Sprayed Concrete for immediate rock support and permanent tunnel linings

The sustainability of sprayed concrete linings (SCL) depends on the composition and amount of concrete and on service life. The RCN and industry-based project SUPERCON (Sprayed sUstainable PErmanent Robotmade CONcrete tunnel linings) was initiated and in this paper, we review the materials, application and key properties of the SCL that are essential for productivity, economy, function, durability and sustainability. We study the term “sprayability” which includes application properties such as rheology, rebound, fallout and compaction, and material properties such as strength and permeability. We suggest investigations to understand sprayability and the properties that affect SCL quality and sustainability.