Dense hard-sphere packings offer a minimal yet powerful platform for exploring disorder to order transitions in athermal materials. Despite extensive progress in colloids and simulations, the microscopic route by which frictional granular assemblies crystallize under cyclic shear and whether such evolution can be captured within an Edwards statistical framework remains insufficiently constrained by experiments. In this work, quasi-static cyclic simple shear is imposed on a three-dimensional packing of 1×10⁴ smooth ABS spheres (diameter ≈ 6 mm) confined in a cubic shear cell. At prescribed cycle numbers, the system is brought back to the zero-strain configuration and scanned using X-ray computed tomography, enabling particle-resolved reconstruction of positions and subsequent statistical analysis in the bulk region away from boundaries. Global packing fraction is determined from Voronoi tessellation, while local structural ordering is quantified via bond-orientational order metrics computed from the twelve nearest neighbors, complemented by a crystal-bond classification that identifies solid-like particles and crystalline clusters.
The packing fraction increases monotonically from an initially loose state, with the global packing fraction equal to 0.636, and reaches a steady plateau after long cycling, with the steady-state global packing fraction equal to 0.70. A pronounced structural crossover is observed near the random-close-packing regime: bond-orientational indicators exhibit a clear kink, coincident with the onset of rapid nucleation and growth of fcc,hcp-like clusters. With further densification, the crystalline fraction saturates, suggesting a dynamical steady state in which shear-induced ordering competes with geometric frustration and topological constraints that stabilize a residual disordered component. To connect structure to an effective thermodynamic description, we analyze Voronoi-volume fluctuations within the Edwards volume ensemble. The fluctuation-based compactivity is extracted along the disordered and crystalline branches, and the Edwards entropy and an effective free-energy density are evaluated. The resulting curves display a branch separation and provide experimental support for an Edwards-style statistical characterization across a shear-driven disorder–order transition in an athermal granular packing.