Crack Sealing Treatments

Portland cement concrete (PCC) began to be used as a surface or wearing course for pavements in the United States in the early 1900s.  The joint sealant or filler materials used during this early construction period were typically sand, tar paper, coal-tar pitch, asphaltic compounds, or wooden blocks.  Material specifications for these early joint filler materials were nonexistent.  The main emphasis of pavement construction during this period was to "get the country out of the mud", not to provide a long lasting flexible joint sealant material to protect the pavement structure.  In the early 1940s, pavement engineers began to concentrate on the construction of the joints in rigid pavements and the materials used to seal those joints.  It was during this time period that elastomeric materials (generally an asphalt-based material modified with crumb rubber) began to be developed for use in pavement joints and the first material specifications were developed to provide a means of quality control.

As user requirements changed (i.e., materials resistant to fuel spill-age, etc.), new materials (typically polymer modified and/or extended coal-tar materials) were introduced and new material specifications were developed. New formulations have continued to be introduced with individual material specifications eventually being developed for each sealant.   

In the 1970's, with the increase in cost in oil, the cost for asphalt used in pavements increased dramatically. The idea of pavement maintenance of existing pavement rather than repaving was born. Crack sealing of asphat pavements was seen as a pavement preservation technique. Initially, the same materials used to seal joints in concrete pavements were used to seal cracks in asphalt pavements. New specifications were developed and formulations improved. Typically, polymer modified asphalts and asphalt rubber materials are used for asphalt crack sealing.