For a utility trench in a residential area, a contractor specifies the use of 'clear stone' for bedding. What size and type of material would typically be considered 'clear stone' in this context, and why is it preferred?

Question: For a utility trench in a residential area, a contractor specifies the use of 'clear stone' for bedding. What size and type of material would typically be considered 'clear stone' in this context, and why is it preferred?

Answer options:

• 20 mm granular A, for maximum compaction and stability. ✅ 19 mm clear crushed aggregate, for its free-draining properties and uniform support.
• 50 mm rounded river stone, for easy placement and minimal pipe damage.
• Porous fill (e.g., screened topsoil), for environmental protection and root growth.

Correct answer: 19 mm clear crushed aggregate, for its free-draining properties and uniform support.

Explanation: 19 mm clear crushed aggregate (e.g., HL3 or similar) is commonly used as 'clear stone' for pipe bedding. Its uniform particle size, angular shape, and lack of fines provide excellent compaction, free drainage, and stable, uniform support around the pipe, preventing point loads. This adheres to typical municipal and engineering specifications for utility bedding.