Research team evaluates best methods for berming in cold regions

Highway

Winter weather is tough on the nation’s roadways. Berming is a common practice for pavement shoulder maintenance, especially in the colder regions of the United States. Effective pavement berming improves load support capacity and prevents vehicle drop-off accidents, but its durability can suffer under the punishment of snow plowing during winter.

A research team led by Xiong (Bill) Yu, professor of civil engineering at Case Western Reserve University put some common types of berm materials and berming equipment to the test, aiming to help transportation agencies improve berms’ resilience and ensure the safety of its workforce while performing these types of repairs.

Their work was included in the March issue of the Journal of Cold Regions Engineering and was featured in the American Society of Civil Engineers’ (ASCE) SmartBrief March 1, and also in the ASCE eNews message to its more than 100,000 members.

The team evaluated four types of berm materials (crushed limestone, two sizes of recycled asphalt pavement (RAP), and natural soil berm) and four commonly used pieces of compaction equipment (a regular vibratory roller, drag-behind roller, side-mounted roller and berm monster) for a total field study of 16 different combinations demonstrated along four miles of test road sections.

The team discovered that crushed limestone performed similarly to RAPs in the field, and that applying a tack coating significantly improves the stiffness of the berm and protects all the tested materials from erosion. They also found the side-mounted roller provides better compaction for both vertical edge and safety edge pavements. Based on the field observation, the team provided recommendations on strategies to improve the equipment design to achieve improved berm compaction while safe guard the operator safety.

Other authors on the paper are: Yuan Guo and Jiale Li, graduate assistants in the civil engineering department; and Qiangbin Huang, professor of geological engineering at Chang’an University in Xi’an, China.