Durability, permeability, and mechanical performance of sprayed UHPC, as an attribute of fibre content and geometric stability

Abstract

Sprayed concrete relies on the presence of an accelerator to set rapidly in place and achieve adequate geometric stability. This significantly reduces its strength, workability, and limits its application to specialised projects whereby the technical advantages of spraying outweigh the limitations rendering it more suitable over conventional placing methods. This study proposes the development of a novel sprayed ultra-high-performance concrete (SUHPC), suited for the application of complex shaped structures, utilising high glass fibre content and thin section requirements to achieve geometric stability. The study assesses the effects of fibre content on the mechanical, permeability, and durability performance of the developed SUHPC, and provides an assessment of its feasibility for spraying complex shaped free form architectural structures. The study found that incorporating high fibre contents in excess of 2 vol% allowed the mix to maintain geometric stability, while attaining ultra-high compressive strengths of up to 144 MPa. Meanwhile the durability and permeability performance remained above the typical threshold for typical UHPC. This study allows the revitalisation of UHPC for sprayed applications, incorporating an all-in-one architectural and structural design solution.