D5121-22 – Standard Test Method Technical Guide

🪚 Apparatus and Specimen Geometry

Practice D5121-22 establishes the standard procedure for the preparation of rock slabs specifically intended for durability testing of erosion control materials. This practice is fundamentally appropriate for the assessment of breakwater stone, armor stone, riprap, and gabion-sized rock materials.

The central piece of apparatus is the rock saw, defined in Section 3.2.1. This term specifically includes the blade (which physically saws the rock), all components that control or power the sawing process, and the supporting framework on which the blade and associated parts are mounted. The standard explicitly recognizes two configurations: the water-cooled diamond blade saw and the diamond wire saw.

The product of this apparatus is the rock slab (Section 3.2.2). A slab is a section of rock having two smooth, approximately parallel faces, produced by these two saw cuts. A key geometric requirement is that the thickness of the slab is