The Importance of Aggregate in Your Sealcoat


Ryan Strzalka SealMaster SoCal


Every spring, the clocks spring forward, marking the official beginning of sealcoat season in Southern California. With warmer days and nights as well as more sunlight throughout the day, the middle of March to the beginning of November offers optimal conditions for sealcoating. Asphalt alone is the most economical choice for HOA roads and parking lots, but without proper maintenance to prolong the life cycle you are allowing the elements to cut your asphalt life cycle in half. Sealcoating is the first step in the extension of the asphalt life cycle, but not all sealcoats are made the same. In this article we will discuss how the inclusion of aggregates in your sealcoat will provide the durability that should come out of your next sealcoat project.


Let’s start off with what “aggregates” are. An aggregate is a hard, inert material that is mixed with a cementing material or binder. Aggregates are incorporated into the mix to form plaster, mortar, or concrete, but they are also used in sealcoating mixes. The most common aggregate used in sealcoating material is silica sand. Silica sand is essentially quartz that has been broken into tiny grains by wind and water.


When properly incorporated into the sealcoat mix, silica sand provides the following benefits:


1. Enhances the pavement traction making the pavement safer for pedestrian, cyclists, and drivers.


2. Enhances the bond between the sealant and the pavement. A strong bond is essential for the longevity of the sealcoating.


3. Helps conceal hairline cracks or other minor flaws giving a more even appearance to your asphalt surface. Please note that sealcoat is not a repair, it is a maintenance product used to prolong the life cycle of your asphalt, not fix pot holes or major infrastructure damage.


4. Aggregates make sealcoat tougher so it can better resist wear from traffic and help with water penetration.


5. Aggregate helps sealcoat dry faster.


In order to ensure that contractors are using the proper amount of aggregate in their sealcoat mix, the board should request that the material be manufactured and delivered to the contractor per


20 May | June 2023


manufacturer’s specification with the aggregate/silica sand and polymers already added to the mix. This material would be called “ready-to-use” and the only addition the contractor will have to make is water to


dilute the material so that it will spread properly. Sealcoat, in its concentrate form, would be too thick to spread and should be diluted per the manufacturer’s specification before being applied. Don’t worry, the water is all part of the process, but be wary of contractors who over-dilute the material to try and get a better spread rate. Too much water will spread the aggregate out too far and could cause early material delamination.


An easy way for a manager to make sure the board is getting the right sealcoat material would be to allow your manufacturer’s representative to recommend contractors for your next project. Manufacturers’ representatives can help managers by setting up their next asphalt job walk with three qualified contractors. This way your board is getting apples to apples bids the first time and all of the contractors are using the proper materials for the project. Representatives can also attend board meetings and help to educate your board members on the benefits and handle the proper expectations of sealcoat.


Not all sealcoat is made the same. Avoid getting the “black water” treatment and make sure your contractors are using a quality product. A quality sealcoat includes aggregates, like silica sand, and polymers that will help strengthen the bond between your asphalt and the sealcoat. Your asphalt will appreciate you for it.


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