Currently, the construction of structural connections within precast floor diaphragms predominantly relies on cast-in-situ or field welding techniques, such as hairpin and welded plate connections, which ensure integrity and reliable force transfer between individual precast floor units. However, these methods present significant challenges for the disassembly and reuse of floor slabs at the end of a building's service life. This paper presents an innovative demountable interlocking web connection that does not rely on traditional welding or bolting methods, thereby facilitating the deconstruction and reuse of precast concrete slabs while expediting the construction process. The connection features an embedded faceplate with specially designed teeth and shear connectors, enabling both in-plane and out-of-plane operational mechanisms. To evaluate the in-plane shear performance and reusability of this novel web connection, a comprehensive experimental investigation was conducted through monotonic loading tests. This study assessed the influence of various factors, including material properties, the configuration of the embedded faceplate, and the number of connectors, on failure modes and load-displacement characteristics. The results indicated that the proposed web connection demonstrated exceptional force transmission capabilities, effectively transferring shear forces through the deformation of the shear connectors. By utilising a faceplate constructed from high-strength steel, shear fractures were effectively confined to the connectors, which can be easily demounted and reinstalled to facilitate slab reuse. Furthermore, the findings revealed that increasing the number of shear connectors did not compromise the shear resistance per connector but significantly enhanced installation efficiency.