Excavated rock materials from tunnels for sprayed concrete

Abstract

Sand extracted from natural resources is widely used in concrete production nowadays. The increase in demand for concrete production has resulted in shortage of natural sand resources, especially in terms of suitable materials for concrete production. At the same time, large amounts of excavated rock materials are and have been generated from tunnelling projects and discarded. Hence, there is an opportunity to use these excavated rock materials as aggregates for concrete production. The challenge lays in the production of suitable aggregates. The focus of the study presented in this paper is on the use of processed excavated rock materials from tunnelling projects as aggregates in sprayed concrete production. Five sand materials, both natural and excavated, have been characterized. The effect of three of these materials’ properties on the workability properties of the resulting spray concrete will be investigated. The study is not completed yet and a final conclusion remains to be drawn.