Crack Sealing FAQ

Information about asphalt pavement crack sealing.

What is it? How it works? Which products?

What To Know

  • There are many types of sealants on the market and the product to use would depend on the application, temperature range, and longevity.

    Cold pour crack sealants are known more as crack fillers.  They are a cheaper method to repair cracks that have a very limited movement range and are suited to cracks that are not very wide.  Cold pours have a tendency to fail under large temperature changes and lose flexibility quickly to limit the effective lifespan.

    Hot pour sealants generally outperform cold pour sealants.  They are formulated for different applications and temperatures.

    In parking lots we would recommend a slightly stiffer product such as a modified ASTM. For driveways or low traffic parking lots, a slightly softer product like ASTM D6690 Type I will provide a longer service life than a modified product.
    Roadways it is recommended to stick to the best sealant matching the climate temperature range.

  • Crack sealants are often classified by their ASTM test rating. 

    ASTM D6690 Type 1 is suited for temperatures between -22C and 60 C.
    It is formerly known as ASTM D1190. This is a trust worthy long term product developed in the 50's.  It is suitable for the Lower Mainland of BC and moderate climates.  It has good performance from  -22C to 40C.

    ASTM D6690 Type II is suited for temperatures between -29 and 60C.  
    It is formerly known as ASTM D3405.  This sealant specification was developed in the 70's to improve performance on D1190 for cold weather and limit movement in hot weather.  It is has good performance from -28C to 40C.

    ASTM D6690 Type III is very similar to Type II but has a bond test on water immersion and an aging test.

    ASTM D6690 Type IV is suited for temperatures between -29 and 60C.  
    It is formerly known as ASTM D3405 Low Modulus.  This sealand is a cold weather sealant where -30 in the winter can commonly happen.  It is a softer sealant than Types I to III.  It has good performance from -30C to 35C.

    ASTM Modified.  These are special sealants that often have design purposes for a use rather than temperature.  Lower quality melters being direct fire ones will often require a modified product to increase the heat resistance during melting through the use of added polymers in the blend.  These products can also be stiffened to a parking lot grade for added peel resistance.  They generally cost more and have a reduced service range. These products will generally have a service range of -18C to 60C.

  • Crack sealants that are heated must be applied to a surface that is free of water or the steam off effect will eliminate the product bond.  We generally recommend no rain or fog 24 hours prior to the application at a minimum.  Freezing temperatures may hold ice which will create the same issues.

    Crack sealant should be installed in temperatures above 4 C.

    Hot weather installations work well but the daytime heat will extend the tack time for the sealant, a traffic flow restriction.

  • Yes.  However night time noice bylaws may make this difficult in some locations.  Also excessive humidity during the night might affect the quality of the bond.  It is also easy to miss cracks in the dark.

  • To rout a crack is to cut the crack open to provide a sealant reservoir.

    Routing cracks opens the cracks up so more sealant can be placed in the crack.  Sealant has an elasticity to it and the wider the crack is, the better movement range the sealant can handle.  Routing cracks will generally more than double the service life of the sealant.

    We recommend sealing cracks that are routed in most cases.  We always recommend routing in locations where winter temps drop below -10.

    Routing is not needed if the cracks are already greater than 10mm wide or it is known that the crack does not move more than 2mm throughout the year.

  • Crack are overbanded when sealed to ensure the entire crack is sealed.  It also help limited capillary action of water through the pavement which when under the sealant will cause it to debond.

    Sometimes when a crack sealant is installed well and there is a lot of movement, the tension on the pavement through the sealant will cause the pavement to crack beside the sealed crack.  Overbanding helps address this issue.

    Non-overbanded sealing is generally for aethetics and used on cold joints.  It can also be done on locations of abrasion where resistance to items such as snow plows can rip off overbanded sealant.

During The Application

  • Yes, asphalt that is heated has a smell.  It is very short lived and will disappear within minutes of the application.  Some people may be sensitive to the smell, but in almost all cases, there is no ill effects as the concentration to a bystander would be too small to cause side effects.

  • Moderate noise can occur from a small engine for the melter.  There most likely will be a short period of loud noise during the operation of a blower / compressor.

    Routing and cleanup can create a longer period of noise. Routing is an optional service. Noise would be similar to a backpack blower.

  • Generally no.  However, the cleaning of the crack may cause projectiles to occur.

    Routing of the crack may also cause projectiles to occur and silica dust.  
    The melters have burning fuel and possible hot torches.

    We recommend people to stay at least 50ft away from the work zone.

  • Cooling to the point where you can walk on it or drive on it will depend on ambient temps, wind, and the volume of material in the crack.

    Generally once sealed, it is ok to open to traffic in 5-15 minutes.  A maximum of approx 30min.

  • Yes, at times people are impatient and believe that closures are only a suggestion.

    If a person gets some on their car or shoe, it can be removed easily and without damage using a degreaser.  We recommend a citrus degreaser and to make sure you are wearing gloves when cleaning.

  • We generally have 3 options to choose.

    1. No detack.  This leaves the sealant tacky until dust, water, or other contaminants are on the surface until it is cold.  Without a detack, the product may track, stick, pull for up to 2 hours after the application.

    2. Sand.  A cleaned sand product works well and provides some added benefits of traction and hides a bit of the product finished surface.  The downside is the sand can get tracked into garages or sidewalks.

    3. Vegetable based oil.  This is the quickest acting and almost the cleanest.  It doesn't look as nice when done as the detack oil agent darkens the pavement around the crack temporarily and can stick to shoes to track onto exterior tiles and make them more slippery.  The oil will go away quickly (24 hours) usually.

After The Application

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What Can Add To The Cost?

  • Yes.  Deweeding takes time.  It is recommended the customer apply a weed killer a month prior to application of sealant to ensure they do not grow back.

  • Dirt asphalt / blacktop will act as a debonder to crack sealant.  Although success of adhesion is unknown, generally excess dirt must be blown off.  If there is too much dirt, a sweeper truck may be needed prior to dust removal.

  • Moss and algae are of the biggest issues when crack sealing.  They are as bad as or worse than weeds.  Time consuming power washing must occur prior to sealing and it will often add significant cost to the job.  Generally, algae and moss are not common as they are often found on untraveled and total shade areas.

  • If there is a busy area that must have traffic restrictions during the work, it can delay the job and add cost.  We recommend closing sections at a time if possible rather than half lanes. There is sometimes the possibility of doing work outside of busy times.

  • Wide cracks can be sealed but success will start to vary once you exceed 1".  After an inch, you are looking at an expansion joint type of repair rather than a simple crack seal.  Depending on the cracking, alternate methods may be suggested.

DISCLAIMER

Not All Situations Are The Same

Information presented from this page are based from our experiences and knowledge. It is presented only as general information to assist in decision making and general procedures. This information may or may not provide accurate and/or appropriate solutions for any specific questions as each situation may vary and require different strategies. Use of the information provided does not hold Roaron Construction responsible for any liabilities, cost, wrong doing, or related expenses incurred from the use of information provided on this site.

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