Reference panels

The appearance of concrete surfaces as-cast is somewhat subjective. Disputes can arise over interpretation of a standard finish. For highway structures, the Manual of Contract Documents for Highway Works (MCHW), Volume 1 Specification for Highway works, Series 1700 Structural Concrete, Section 1708 Concrete - Surface finish deals with formed finishes under classes F1 to F5.

To help with the assessment of as-struck finishes, the CBDG responded to an approach from the Highways Agency (now National Highways) to manufacture and install concrete panels demonstrating typical finishes. The 2m x1m two-sided panels were originally located at 8 strategic sites throughout UK although now only 4 remain. Each is cast from local materials and cast against birch ply, medium density overlay (MDO) and steel plate.

Since their installation in 2002, there has been debate over the true usefulness of these panels. As part of the current overhaul of the MCHW the reference to the panels may be removed, although this is not expected until 2024-25.

The following guidance notes were produced to complement physical viewing and assessment at each location and cover the two main classes F2 and F4.