Pavements

Pavement is a durable surface laid down on roads, sidewalks, courtyards and other outdoor areas to support pedestrian and vehicular traffic. In American usage, pavement often refers to the road surface itself, while in British English pavement means a sidewalk. The surface is supported by a subbase and subgrade to provide strength, drainage, and frost protection.

Materials include asphalt concrete (bituminous), Portland cement concrete, natural stone, brick, and interlocking concrete or clay pavers. Some surfaces incorporate permeable materials to improve drainage and reduce runoff. The choice of material depends on traffic loads, climate, drainage, noise considerations, and maintenance costs.

Design aims: distribute loads, provide skid resistance, be durable, safe in wet or icy conditions, facilitate drainage and maintenance. Mechanistic-empirical design and AASHTO methods are used in many jurisdictions; life-cycle cost analysis informs selection.

Construction: typical sequence includes subgrade preparation, subbase, base course, and surface layer (asphalt or concrete). Asphalt pavements are laid hot and compacted; concrete is rigid and cured with joints. Maintenance includes crack sealing, pothole repair, resurfacing, and mill-and-fill.

Types include flexible (asphalt), rigid (concrete), composite, and interlocking or modular pavements (pavers). Permeable pavements use permeable aggregates or voided textures to allow infiltration.

History and impact: pavements date back to ancient civilizations with stone or gravel surfaces. Modern asphalt and concrete pavements emerged in the 20th century and underpin modern road networks. Environmental considerations include recycling, reduction of heat islands, and stormwater management.