The development and application of seawater sea-sand concrete (SSSC) can effectively reduce the utilisation of natural resources for producing concrete, thereby protecting ecological environments. However, the durability of reinforced SSSC is an important aspect. Previous studies have shown that the addition of fibres and expansive agents (EAs) can improve the durability of reinforced concrete structures by controlling crack development, reducing concrete porosity, and enhancing the tensile strength of concrete. In this study, the compressive behaviour of SSSC containing glass fibres (GFs) and EAs was studied. Furthermore, tests were performed to evaluate the combined effects of fibre length, GF content, and EA content on the workability of fresh concrete and the failure mechanism, compressive strength, strain at peak stress, and toughness of hardened concrete. It was found that the addition of GFs and EAs significantly improved the compressive performance of SSSC. The characteristics of compressive stress-strain curves were analysed and a constitutive model that could simulate the compressive stress-strain relationship of SSSC containing GFs and EAs was proposed. These outcomes are expected to provide experimental support and theoretical guidelines for designing SSSC structures. (c) 2021 Elsevier Ltd. All rights reserved.