Maintenance and Rehabilitation

Flexible Pavement Maintenance

An overview of techniques used for preventive and corrective maintenance on flexible pavements.

Bituminous Surface Treatments

A bituminous surface treatment (BST), also known as a seal coat or chip seal, is a thin protective wearing surface that is applied to a pavement or base course. BSTs can provide all of the following: A waterproof layer to protect the underlying pavement. Increased skid resistance. A filler for existing cracks or raveled surfaces. … Read more »

Non-Structural Overlays

Non-structural overlays (Figure 1) do not involve extensive structural design and generally contribute little, if anything, to a pavement’s structural capacity. Non-structural overlays are generally thin surface overlays on the order of 12.5 mm (0.5 in.) to 37.5 mm (1.5 in.) that are used to (NAPA, 1995[1]): Improve ride quality. Correct minor surface defects. Improve … Read more »

Slurry Seals

A slurry seal is a homogenous mixture of emulsified asphalt, water, well-graded fine aggregate and mineral filler that has a creamy fluid-like appearance when applied. Slurry seals are used to fill existing pavement surface defects as either a preparatory treatment for other maintenance treatments or as a wearing course. There are three basic aggregate gradations … Read more »


Rejuvenators are products designed to restore original properties to aged (oxidized) asphalt binders by restoring the original ratio of asphaltenes to maltenes. Many rejuvenators are proprietary, making it difficult to offer a good generic description. However, many rejuvenators contain maltenes because their quantity is reduced by oxidation. Rejuvenators will retard the loss of surface fines … Read more »

Fog Seals

A fog seal is a light application of a diluted slow-setting asphalt emulsion to the surface of an aged (oxidized) pavement surface. Fog seals are low-cost and are used to restore flexibility to an existing HMA pavement surface. They may be able to temporarily postpone the need for a surface treatment or non-structural overlay. Purpose … Read more »

HMA Patching

Patches are a common method of treating an area of localized distress. Patches can be either full-depth where they extend from the pavement surface to the subgrade (Figure 1) or partial where they do not extend through the full depth of existing pavement (Figure 2). Full-depth patches are necessary where the entire depth of pavement … Read more »

Crack Seals

Crack seal products are used to fill individual pavement cracks to prevent entry of water or other non-compressible substances such as sand, dirt, rocks or weeds. Crack sealant is typically used on early stage longitudinal cracks, transverse cracks, reflection cracks and block cracks. Fatigue cracks are most often too extensive to warrant filling with crack … Read more »




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