CRACK SEALING
EVERYTHING YOU NEED TO KNOW ABOUT CRACK SEALING
Information about cracks sealing is based on the company internal research based on the following materials. Links for Selected materials:
Crafco Crack Sealing Instruction Manual.wmv – YouTube
Crack Sealing Asphalt Pavement Video (Part One) – YouTube
Crack Sealing Asphalt Pavement Video (Part Two) – YouTube
Materials and Procedures for Repair of Joint Seals in Portland Cement Concrete Pavements. Manual of Practice.
FHWA Report No. FHWA-RD-99-147
Surface Condition Rating Manual for Alberta Transportation
WHY SEAL CRACKS IN ASPHALT PAVEMENT?
– Crack sealing is very cost effective procedure of pavement maintenance that adds years to its life. It stops moisture to penetrate to sub base bringing deterioration of pavement. Neglecting the cracks leads to their further acceleration and other types of pavement failures.
FHWA Report No. FHWA-RD-99-147
Materials and Procedures for Sealing and Filling Cracks in Asphalt-Surfaced Pavements:
Cracking in asphalt concrete (AC)-surfaced pavements is a phenomenon that pavement design and maintenance engineers have had to contend with for years. It is one of two principal considerations (fatigue cracking and rutting) in the pavement design process, and it is often the primary mode of deterioration in AC pavements. Cracks are inevitable, and neglect leads to accelerated cracking and potholing, further reducing pavement serviceability.
Alberta
The main purpose of a crack treatment is to seal or fill the crack in order to prevent moisture from penetrating the base and subgrade thereby preventing the weakening of the roadway structure. The secondary purpose is to prevent the loss of aggregate from the edges of the cracks. Moisture entering the crack can lead to accelerated fatigue, stripping, pumping and other pavement damage. Crack maintenance encompasses many treatment options ranging from the basic maintenance application of crack filling to more drastic measure of overlaying the pavement.
Research Project 0-4061-P3 Comparison of
Hot-Poured Crack Sealant to Emulsified Asphalt Crack Sealant
Pavement cracking is an inevitable phenomenon that maintenance engineers have to accustom themselves to. It is impossible to construct a pavement that does not develop cracks after a certain amount of service time. Cracking is one of the two main concerns considered in the pavement design process (the other being rutting); it is the primary mode of deterioration in asphalt cement pavement. Cracking occurs in a variety of forms: transverse, longitudinal, block, and alligator shape. Cracks need to be treated promptly because they create openings for moisture to penetrate the pavement layers. Moisture or water can cause severe damage when trapped in the crack. Neglecting pavement cracking usually leads to accelerated deterioration of the pavement, resulting in significant problems such as potholes or base failures, which cause the serviceability of the pavement to decline. Cracking, since it is such a major form of pavement deterioration, is usually the deciding factor in determining the proper time for rehabilitation and the appropriate method to be applied. When cracks develop on the surface of the pavement, it is a sign of reduction in pavement integrity and serviceability. Regular repair of pavement cracks is one of the main methods of preventive maintenance, since failure to repair cracks in a timely fashion can lead to accelerated deterioration of the pavement in the form of crack growth, spalls, secondary cracks, and potholes. The main causes of pavement cracks are thermal movements and fatigue due to excessive loading. Cracking is an inevitable problem given the network of more than two million miles of asphalt surfaced roads in the United States. It is important to find effective solutions to minimize its effect and to extend the service life of our roads.
Is it LATE to take care of your cracks?
FHWA Report No. FHWA-RD-99-147
Materials and Procedures for Sealing and Filling Cracks in Asphalt-Surfaced Pavements:
In general, a large number of cracks or severely deteriorated cracks indicate a pavement in an advanced state of decay. Crack sealing or filling in these circumstances is both uneconomical and technically unsound, as it does little to delay the need for more extensive corrective actions.
Research Project 0-4061-P3 Comparison of
Hot-Poured Crack Sealant to Emulsified Asphalt Crack Sealant
Ideal pavement candidates for this technique exhibit minor pavement distress and have sufficient struc¬tural capacity to meet present and future structural needs. Pavements with transverse and longitudinal cracks are good candi¬dates for crack sealing, but pavements with fatigue and alligator cracking, as displayed in Figure 1, should not be subjected to this maintenance technique. Fatigue and alliga¬tor cracking indicates pavement structure failure, and crack sealing will not extend the life cycle of this type of pavement con¬dition.
Alberta
Careful consideration must be given to existing pavement condition to ensure a successful treatment. Crack density and edge deterioration are two major factors in deciding what treatments to apply. If a pavement is badly deteriorated, and has significant cracking, crack filling or crack sealing may not be the most effective treatment on a life cycle cost basis.
Crack Density
Crack density is a measure as to how closely spaced the transverse cracks are on a given length of roadway. The following table was developed by the Michigan Department of Transportation to determine crack density.
DETERMINING THE APPROPRIATE CRACK MAINTENANCE APPLICATION
TWO TYPES OF CRACK TREATMENT
Crack sealing – the process that should be performed on a pavement that are in good condition. Good condition is defined as the pavement that has a sound base that exhibits distress in the form of thermal or moving cracks spaced near or over 10 feet apart. The procedure consist of routing and sealing the cracks.
Crack filling – this procedure consist of filling closely spaced (less than 10 feet apart), random cracks that connects to each other or not moving cracks. For this method crack routing is not recommended.
CRACK TREATMENT OPTIONS – SEALING VERSUS FILLING
Crack sealing and crack filling are two distinct activities and it is important to understand the differences between the two treatments to effectively treat the cracks.
Crack sealing is a more intensive operation that is intended to prevent water from entering the pavement structure. The treatment involves routing the crack to a specific configuration and placing a high-quality sealant in it.
Crack filling is a less intensive operation and is intended to reduce the amount of water infiltration into the pavement and reinforce the adjacent pavement. This treatment involves placing a crack filler into the crack without affecting the crack geometry.
