The geometrical characteristics of recycled sands, particularly particle shape and particle size distribution (PSD), strongly influence their interparticle friction, packing behaviour, and suitability for construction applications such as screeds and concrete mixes. This study explores the relationship between the particle shape and PSD resulting from the manufacturing process and the internal angle of repose (AoR), a proxy for granular flowability and interparticle friction, in secondary sands derived from construction and demolition waste. Particle shape was analysed using digital methods (laser diffractometry for the finest fractions and image analysis for large particles). The results reveal that the angle of repose is governed by a complex combination of effects from the particle shape, surface texture, and fines content. While particle angularity is considered a significant drawback of secondary manufactured sands in applications such as production of screed, mortar and concrete, the surface roughness and content of fines emerged as the primary challenges to address. The angle of repose offers a practical metric for assessing recycled sands, but its significant variability, particularly in heterogeneous waste streams, highlights its limitations as a standalone indicator of interparticle behaviour. The study underscores the need for integrated morphological and granulometric characterization to reliably evaluate secondary sands for high-value applications.