The impact of cold weather and high night-time traffic on aggregate stripping of a single seal: a case study at Beaufort West, South Africa

The R61 is a major road link between the Western Cape and the Eastern Cape. During the reseal of a portion of this road premature stripping of the single seal aggregate from the modified binder tack coat occurred. Although the average daily traffic is fairly low, the road caters for the high volumes of high-speed bus and minibus traffic over weekends for those commuters travelling to the Eastern Cape. This high weekly differential of speed and volumes, in conjunction with sudden low nighttime's temperatures and sensitive modified binder, resulted in stripping of the aggregate from the seal on some sections of the road. The narrow road widths and resultant channelized traffic flow patterns also contributed to the lack of embedment of the aggregate between the wheel tracks. This paper investigates the causes, repair methods and recommends preventative actions and procedures to limit future recurrences of these failures. (a) For the covering entry of this conference, please see ITRD abstract no. E220163.