Which distress manifest as interconnected cracks forming small blocks?

Block cracking is the distress that manifests as interconnected cracks forming small, approximately rectangular blocks on the pavement surface. This type of cracking is characterized by large, interconnected cracks that divide the pavement into blocks typically ranging from 0.3 to 3 meters (1 to 10 feet) in size. The cracks are usually shallow and may not extend through the entire asphalt layer. Block cracking is primarily caused by shrinkage of the asphalt surface due to temperature changes and asphalt binder aging. As the asphalt ages, it becomes stiffer and less flexible, making it more susceptible to cracking. Temperature fluctuations cause the asphalt to expand and contract, and this repeated expansion and contraction can lead to the development of tensile stresses in the pavement. When these tensile stresses exceed the tensile strength of the asphalt, block cracks begin to form. The presence of block cracking can allow water to enter the pavement structure, leading to further deterioration, but it is not usually considered a structural failure unless the blocks become loose or displaced.