How Asphalt Paving Works: Why Tamarac Pavement Cracks First
Asphalt is only the top of the pavement. A residential surface is 3 to 5 inches of asphalt over a 4 to 8 inch rock base, and the base does most of the work. When water weakens that base, the asphalt above it flexes under tires, cracks and breaks apart. Poor drainage and a weak base or poor compaction are what damage a surface most.
Tamarac’s ground makes this worse. The sandy soils mapped in the area, such as Hallandale, Margate and Pompano fine sand, can have a water table as shallow as 6 inches in the wet months. A base sitting that close to water loses strength when it is soaked, so the wheel paths crack first and potholes follow.
The rain adds to it. Tamarac’s rainy season runs from May 15 to October 15 and brings nearly 70% of the year’s rain. Water enters through every open crack, softens the stone and widens the damage, which is why small cracks should be fixed right away. A paving contractor in South Florida makes the same point: fix a drainage problem first, or you will end up spending twice as much. Good paving is therefore mostly about the base, the drainage and the compaction under the surface. The asphalt on top is what you see, but the work under it decides whether the pavement is still smooth in ten years.