Which of the following type of coarse aggregate is preferred in road construction, so that greatest density of road layer is achieved?

Any type of aggregates:

• This statement is incorrect.
• Using any type of aggregates without considering their size, shape, and grading can result in poor compaction and lower density of the road layer.
• Randomly mixed aggregates can create irregularities and weak points in the road structure.
• Such aggregates do not ensure uniform distribution and bonding, leading to potential road failure under load.

Single-size aggregates:

• This statement is incorrect.
• Single-size aggregates can lead to voids in the compacted layer because they do not pack together efficiently.
• This results in lower density and reduced strength of the road layer.
• The lack of smaller particles to fill gaps means the structure can shift and settle over time, decreasing road longevity.

All-in aggregates:

• This statement is correct.
• All-in aggregates, which include a mix of various sizes, tend to fill voids more effectively, leading to better compaction and higher density.
• This results in a stronger and more stable road layer.
• The variety of sizes allows for a more interlocked structure, enhancing the load-bearing capacity and durability of the road.

Porous aggregates:

• This statement is incorrect.
• Porous aggregates are not preferred for achieving high density in road construction.
• They have high void spaces and do not compact well, resulting in lower density and potential stability issues.
• Such aggregates can absorb water, leading to freeze-thaw damage and weakening of the road structure over time.