Thermal properties of lightweight dry-mix shotcrete containing expanded perlite aggregate

This paper describes the thermal properties of lightweight dry-mix shotcrete using expanded perlite aggregate (EPA). Mixes made with different EPA/sand ratios were sprayed through the dry-mix shotcreting technique onto wooden molds to produce panels for mechanical and thermal testing. The density, uniaxial compressive strength (UCS), splitting tensile strength (STS), and the ultrasonic pulse velocity (UPV) were measured at various ages. Further, the ISO approved transient plane source (TPS) technique was employed to measure the thermal properties at 28 days. The results illustrate that shotcrete mixes with EPA have similar UCS and superior STS compared to cast concrete. Adding EPA led to a drop in thermal conductivity and diffusivity. When compared with cast concrete, shotcrete had lower specific heat capacity. This study found dry-mix shotcrete incorporating EPA at up to 75% sand substitution as a mechanically viable and thermally resistant alternative to cast concrete containing regular aggregates.