A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Crack sealants are often utilized as a preservation tool in asphalt pavements. These sealants are placed in cracks to prevent water intrusion into the pavement foundation. By reducing water intrusion, the strength of foundation layers is maintained and acceptable pavement performance is extended. However, when a hot mix asphalt overlay is placed on top a pavement containing crack sealants, a bump and additional transverse cracks sometimes occur in the new asphalt overlay. These bumps and sometimes, transverse cracks are initiated during breakdown rolling and become progressively more severe upon further compaction. This paper presents results ofa five-year study designed to identify factors that relate to the appearance of these bumps and consequent cracks. Results of the study indicate that vibratory breakdown rolling, pavement gradient, sealant geometry, tack coat application rate and tack coat adhesivity are factors that contribute most to the occurrence of bumps and transverse cracks during asphalt overlay construction over crack sealants.Observations suggest that transverse bumps and consequent cracks occur in proportion to the size of the ‘bow wave’ of asphalt concrete present immediately in front of the breakdown roller. The increase in the ‘bow wave’ size is dependent on asphalt mixture properties, breakdown roller size, speed, vibration characteristics and pavement gradient. Four pavement test sections also indicate that tack coat application rate and adhesive properties also have an effect on reducing the appearance of transverse bumps.
Crack sealants are often utilized as a preservation tool in asphalt pavements. These sealants are placed in cracks to prevent water intrusion into the pavement foundation. By reducing water intrusion, the strength of foundation layers is maintained and acceptable pavement performance is extended. However, when a hot mix asphalt overlay is placed on top a pavement containing crack sealants, a bump and additional transverse cracks sometimes occur in the new asphalt overlay. These bumps and sometimes, transverse cracks are initiated during breakdown rolling and become progressively more severe upon further compaction. This paper presents results ofa five-year study designed to identify factors that relate to the appearance of these bumps and consequent cracks. Results of the study indicate that vibratory breakdown rolling, pavement gradient, sealant geometry, tack coat application rate and tack coat adhesivity are factors that contribute most to the occurrence of bumps and transverse cracks during asphalt overlay construction over crack sealants.Observations suggest that transverse bumps and consequent cracks occur in proportion to the size of the ‘bow wave’ of asphalt concrete present immediately in front of the breakdown roller. The increase in the ‘bow wave’ size is dependent on asphalt mixture properties, breakdown roller size, speed, vibration characteristics and pavement gradient. Four pavement test sections also indicate that tack coat application rate and adhesive properties also have an effect on reducing the appearance of transverse bumps.
Preventing Transverse Bumps and Cracks in New Asphalt Overlays over Crack Sealants
S. Shuler (author)
2017
18 pages
Report
No indication
English
Adhesives & Sealants , Transportation , Road Transportation , Highway Engineering , Civil Engineering , Construction Equipment, Materials, & Supplies , Soil & Rock Mechanics , Asphalt pavement reconstruction , Transverse Bumps , Full-depth reclamation , Asphalt emulsions , Asphalt pavement rehabilitation , Asphalt overlays , Sealants , Pavement foundation