Here's an updated tiling gravel material created using photogrammetry in Reality Capture, with mesh repair and texture baking in Max. I used Knald for normals to height, Alchemist for tweaks and Artomatix for seam removal and texture mutation to extrapolate a 0.5m square source material into a 2m square seamless one. The gravel piles base geo was created using Gaea and Some vertex colour was baked in Max, to allow some per mesh colouration when the tiling material was dialed in. Look dev and rendering in Toolbag 4.
Gravel piles
Gravel piles
Texturing breakdown, the mound geometry was created in Max with a height map from Gaea
Moving light source, there is fencing geometry at the scene edges for reflections and shadows