Optimisation of the mechanical properties of Miscanthus lightweight concrete

•Demonstration of load-bearing capacity of Miscanthus concrete.•Impact analysis of variation of mixture composition.•Identification of density/compressive strength relation of Miscanthus concrete.•Measurement of shrinkage deformation of Miscanthus lightweight concrete. In this paper, Miscanthus fibres are used to develop lightweight concrete. The amount of Miscanthus and cement, as well as the water/cement ratio, are varied to analyse the behaviour of the mixture concerning the physical and mechanical properties. The Miscanthus was pre-treated with a silicate sealant or a cement-based fluid. The current paper analyses the impact of the pre-treatment of the Miscanthus fibres on the compressive strength as well as on the long-term deformations. The specimens with a pre-treatment based on a silicate sealant reached a compressive strength of 19.3 MPa, which is higher than the compressive strength of a conventional LC 16/18, a Young’s Modulus above 9.9GPa and a shrinkage deformation of 2244μm/m. Nevertheless, considering the density the pre-treatment showed not to be beneficial.