Bitumen Emulsion for Chip Seal
Bitumen Emulsion for Chip Seal offers an economical and efficient method of road life extension by surface protection and improving aggregate retention.
Asphalt roads naturally degrade over time by erosion, raveling, loss of aggregate, honeycombing, and sulphate attack, commonly hastened by weather conditions like frost, heat, sun, and salting of roads. Mechanical loads such as snowplow removal, overloading, tire chaining, and snowplow blades also accelerate this wear. If left untreated, the damages will propagate, leading to total surface failure and additional deeper structure damage.
Protective Surface Layers for Road Preservation
Protective coatings like chip seals slow down deterioration, maintain road condition, reduce development of cracks, and delay costly asphalt overlays. They also provide waterproofing that safeguards the asphalt surface as well as the layers beneath it against further damage. This low-cost maintenance practice keeps roads safe and operational for longer periods.
The type of treatment is based on pavement condition, traffic loading, and type of asphalt. Preventive application, even prior to visible distress, extends the life of the road.
What is a Chip Seal?
A chip seal is a process where a layer of bitumen emulsion is sprayed onto a surface of an existing road, and then distributing chips of aggregate over the emulsion instantly. Chips are then rolled into the asphalt binder for incorporation. Our chip seal emulsions come with special formulation with polymer and rejuvenating agents to enhance workability and retention of chips.
Chip seals are best used on moderately trafficked roads (about 300 vehicles per day). On higher trafficked roads, chip seals are mixed with asphalt overlays, slurry seals, or micro-surfacing layers for enhanced durability.
Terminology Used in Chip Sealing
Chip Seal: Spread of emulsified asphalt, overlaid by a single layer of aggregate. Double or triple chip seals are made using multiple layers.
Surface Treatment/Seal/Dressing: Chip seal application synonyms.
CRS-2: Cationic rapid setting emulsified asphalt.
RS-2: Anionic rapid setting emulsified asphalt.
CRS-2P/RS-2P: Polymer-modified rapid setting emulsions with enhanced performance.
HFRS-2P: High-float polymer-modified anionic emulsion.
CSS-1h/CRS-1h: Slow and rapid setting emulsions for use in fog seal.
Advantages of the Use of Asphalt Emulsions over Hot Asphalt
Bitumen emulsions are used at extremely low application temperatures compared to hot asphalt, resulting in substantial savings in energy and enhanced safety while applying.
Chip Seal Application Process
Preparation: Seal large cracks and patch potholes and allow them to dry.
Cleaning: Sweep away debris using rotary brooms or power sweepers to ensure good adhesion.
Emulsion Application: Apply a uniform layer of bitumen emulsion on the surface.
Aggregate Spreading: Spread chips of aggregates evenly using mechanical spreaders.
Rolling: Compact the chips into the emulsion using pneumatic-tired rollers to achieve good bonding.
Final Cleanup: Scrape loose chips off after curing for a smooth, hard surface.
Pavement Condition and Chip Seal Effectiveness
Cracking: Chip seals work best on uncracked or lightly cracked pavement. Cracks up to ¼ inch in width can be sealed, but larger cracks must be sealed prior to chip sealing. Chip seals also stop moisture intrusion in fatigue or block cracking but lose effectiveness if severe damage.
Flushing: Surfaces being flushed lose friction and result in aggregate embedment issues. Chip seals can recover friction but, in certain situations, will require lower emulsion rates in wheel paths to avoid making flushing worse. Spray rates can be adjusted, and nozzles to regulate this.
Surface Texture: Surface roughness influences the amount of emulsion applied. Tests like the sand patch test need to manage variations in emulsion application rates. Pre-application mapping of surface texture maximizes the result.
Summary
Bitumen emulsion chip sealing is an economical, efficient means of preserving asphalt roads by protecting them against environmental deterioration including UV, freeze-thaw, heat, salt, snowplowing, and heavy traffic wear. The treatment forms a watertight coat over cracks, stopping water seepage and accelerating deterioration. Reducing road softening and skid, and decreasing future maintenance costs, is realized by applying emulsion and aggregate chips.
Chip seals are best suited for low-volume roads but may be used in combination with other treatments for higher-volume streets. Proper evaluation of pavement condition and surface texture ensures optimal emulsion application and long-term performance.
