Cape Seals

What? A cape seal is an application of a chip or scrub seal followed by the application of slurry seal or microsurfacing at a later date.

Why? The chip or scrub seal serves to seal and bond the cracks in the existing pavement. The slurry seal or microsurfacing serves to improve the chip retention and smoothness of the driving surface.

When? Cape seals are typically applied on an intermittent, project-specific basis. Location, weather, traffic loading, and pavement conditions are factors used to determine if a cape seal application is appropriate. Roadways selected for cape seal treatments are commonly those which have moderate distress, limited or no rutting, moderate crack widths, and in which a cape seal treatment would help extend the pavement life until rehabilitation or reconstruction can be performed. Typically cape seals are applied in residential streets where a chip seal would create a rougher surface.

How? The chip or scrub seal is first applied. The slurry seal or microsurfacing treatment follows after, typically around a week later. Time is needed for the chip or scrub seal to receive traffic and for any loose crushed rock to be removed before the slurry seal or microsurfacing is placed.

For more details, refer to the following sections of LA County Special Provisions - Section R - Roadway :

SECTION 904 - POLYMER MODIFIED EMULSION (PME) CHIP SEAL
SECTION 905 - ASPHALT REJUVENATING EMULSION (ARE) CHIP SEAL
SECTION 907 - TIRE RUBBER MODIFIED PAVING ASPHALT (TRMPA) CHIP SEAL
SECTION 906 - SCRUB SEAL COAT
SECTION 203-5 - SLURRY SEAL
SECTION 302-4 - SLURRY SEAL SURFACING
SECTION 908 - POLYMER MODIFIED EMULSIFIED ASPHALT-RECLAIMED ASPHALT PAVEMENT AGGREGATE SLURRY SEAL (PMERAPAS)
SECTION 909 - MICROSURFACING

Sources for more information:
LA County Special Provisions - Section R - Roadway (2015 Edition)