Crack sealing is often a cost-effective preventive
maintenance strategy for prolonging pavement service life when applied to
pavements in relatively good condition. However, crack sealing is often
applied to pavements with extensive cracking. The application of crack sealing
to pavements with extensive cracking can pose a skid resistance hazard.
This
study investigates the relationship between the amount and distribution of
crack sealant application and pavement skid resistance. Locked-Wheel Skid
Tester (LWST) testing was conducted on six pavement projects in North Carolina
with varying amounts and patterns of crack sealant. Images of the locations of
LWST testing were obtained and processed to determine the percentage of the
pavement lane and wheel path area covered by crack sealant. A
relationship between the percentage of the wheel path covered by crack sealant
and LWST results was established that demonstrates the application of high
amounts of crack sealant to the wheel path can pose safety hazards.
The effect
of crack sealant on pavement skid resistance is a function of the existing
pavement’s frictional characteristics. The extent of crack sealant application
to the wheel path is related to the extent and severity of alligator cracking
prior to crack sealing. The results of this study highlight the need for the development of
guidelines to prohibit crack sealant applications to roadways where it could
pose a skid resistance hazard. Based on the results of
this study, it is proposed that these guidelines prohibit crack sealing of
pavements with marginal existing skid resistance (i.e., Skid Number (SN) values
less than or equal to 37). Furthermore, it is recommended that pavements with
good existing skid resistance (i.e., SN values greater than or equal to 43)
should not be sealed if the alligator cracking index falls below 75 for
low-volume roads and 92 for high volume roads to ensure safety.
