Pavement Cracking is an Inevitable

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    Cracks occur for a variety of reasons. There are different types of cracks, below we will explain the different types and the proper ways to approach the problems. A proper maintenance plan should have crack being addressed yearly!

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Alligator Cracking

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Alligator cracking is a load associated structural failure. The failure can be due to weakness in the surface, base or sub grade; a surface or base that is too thin; poor drainage or the combination of all three. It often starts in the wheel path as longitudinal cracking and ends up as alligator cracking after severe distress.

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FIX: Because a structural failure is taking place the only possible solution to alligatoring is to perform a full-depth patch.

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Block Cracking 

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Block cracks look like large interconnected rectangles (roughly). Block cracking is not load-associated, but generally caused by shrinkage of the asphalt pavement due to an inability of asphalt binder to expand and contract with temperature cycles. This can be because the mix was mixed and placed too dry; Fine aggregate mix with low penetration asphalt & absorptive aggregates; poor choice of asphalt binder in the mix design; or aging dried out asphalt.

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FIX: Less severe cracks measuring 1 1/2 inch or less can be sealed to prevent moisture from entering into the sub grade. More severe cracks should be fixed by removing the cracked pavement layer and replacing it with an overlay.

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Longitudinal (Linear) Cracking

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Longitudinal cracking are cracks that are parallel to the pavements centerline or laydown direction. These can be a result of both pavement fatigue, reflective cracking, and/or poor joint construction. Joints are generally the least dense areas of a pavement.  

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FIX: Less severe cracks measuring 1 1/2 inch or less can be sealed to prevent moisture from entering into the sub grade. More severe cracks should be fixed by removing the cracked pavement layer and replacing it with an overlay. 

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Transverse cracks

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Transverse cracks are single cracks perpendicular to the pavement's centerline or laydown direction. Transverse cracks can be caused by reflective cracks from an underlying layer, daily temperature cycles, and poor construction due to improper operation of the paver.

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FIX: Less severe cracks measuring 1 1/2 inch or less can be sealed to prevent moisture from entering into the sub grade. More severe cracks should be fixed by removing the cracked pavement layer and replacing it with an overlay.

 

Edge Cracks

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Edge Cracks travel along the inside edge of a pavement surface within one or two feet. The most common cause for this type of crack is poor drainage conditions and lack of support at the pavement edge. As a result underlying base materials settle and become weakened. Heavy vegetation along the pavement edge and heavy traffic can also be the instigator of edge cracking. 

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FIX: The first step in correcting the problem is to remove any existing vegetation close to the edge of the pavement and fix any drainage problems. Crack seal/fill the cracks to prevent further deterioration or remove and reconstruct to full depth fixing any support issues.

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Joint Reflection Cracks

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These are cracks in a flexible pavement overlay of a rigid pavement (i.e., asphalt over concrete). They occur directly over the underlying rigid pavement joints. Joint reflection cracking does not include reflection cracks that occur away from an underlying joint or from any other type of base (e.g., cement or lime stabilized). 

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FIX: For less severe cracks measuring 1 1/2 inch or less can be sealed to prevent the further entry of moisture into the subgrade. If the cracks are more severe the removal of the cracked pavement layer followed by an overlay may be required.

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Slippage Cracks

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Slippage cracks are crescent-shaped cracks or tears in the surface layer(s) of asphalt where the new material has slipped over the underlying course. This problem is caused by a lack of bonding between layers. This is often because a tack coat was not used to develop a bond between the asphalt layers or because a prime coat was not used to bond the asphalt to the underlying stone base course. The lack of bond can be also caused by dirt, oil, or other contaminants preventing adhesion between the layers. 

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FIX: All of the areas exhibiting the “stretch marks” will need to be removed and will require a partial or full depth patch.

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Concrete Cracks and Joints

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There are two types of joints in concrete slabs, expansion joints and crack control joints. Every concrete slab inside (basements, garages, warehouses) or outside (driveways, patios, entries, walkways, pool decks) are required to have joints every eight feet horizontally and vertically. This blog will try to answer the many questions that people have about driveway expansion joints. What are concrete expansion joints for? What is the difference between an expansion joint for concrete and a concrete control joint (also known as a crack control joint or a construction joint)? 

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What is an Expansion Joint? - These joints provide space between concrete slabs as a buffer for expansion on hot days and contraction when it is cold. Joints vary in size from half-inch to an inch in width and three to four inches in depth.These expansion joints are installed when the original concrete is poured. A slab without expansion joints will crack where the joint should have been. Cracking destroys the look of the concrete as well as reduces the life of the concrete slab. These joints will crack all the way to the bottom of the concrete.

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What are Crack Control Joints? - These joints allow cracking in a controlled area as the slab settles over time. These are also known as break joints, construction joints or saw-cut joints. Usually these are cut into the slab after the concrete hardens. Crack control joints vary in size from one-eighth inch to one-quarter inch in width and half inch in depth. A slab without these joints will crack in random patterns which ruins the look of the concrete as well as allows for damage from water intrusion and freeze-thaw which will reduce the life of the slab.

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PMOH has different techniques and materials to handle concrete joints problems. We have Cold and Hot Black material and we have Cold and Hot Grey Material.

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Let us make it easy for you, let one of our friendly estimators come out and evaluate your Cracks at no charge.

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