PennDOT LTAP technical dot7.state.pa.us（PennDOT LTAP技术dot7.state.pa.us）.pdf

PennDOT LTAP technical INFORMATION Introduction to Crack Sealing SHEET #132 Water is the most destructive element to our pavement. Water entering our roadway through cracks S U M M E R 2 0 0 7 accelerates the deterioration of the roadway. In time, the water will undermine and weaken the roadway base material creating cracks and potholes. Sealing pavement cracks to prevent water from entering the base and subbase will extend the pavement life from 3 to 5 years. Before the advent of high performance, polymer modifi ed asphalt sealants, many municipalities fi lled cracks with AC-20, emulsions, J-1 and cutbacks, known as fi llers. Fillers did fi ll the void in the crack but had little fl exibility to move with the crack in cold temperatures and not fl ow or bleed in high temperatures. Pavements expand and contract with seasonal temperature changes. Consequently, cracks and joints are expanding and contracting when the pavements move. Sealing the cracks with fl exible rubberized asphalt that bonds to the crack walls and moves with the pavement will prevent water intrusion. As part of a Pavement Management System, crack sealing can reduce pavement deterioration by restricting water penetration into underlying base and subbase layers. This restriction helps to maintain pavement structural capaci