As with the university-owned fleet regulations described in Objective #3.1, we aim to implement best practices for all transportation assets falling under campus jurisdiction. Objective #3.2 addresses our extensive system of university-owned streets.[1] Optimizing road surfaces should be taken just as seriously as optimizing the efficiency of the vehicles that drive on them. Smooth pavements also encourage the use of bicycles, and provide a more pleasing aesthetic for the campus.

The key metric for this objective is Pavement Condition Index (PCI), “a numerical rating resulting from a pavement condition survey that represents the severity of surface distresses.”[2] This metric provides a standardized process to quantify road quality. For example: Are there numerous potholes, cracks, or bumps? Do vehicles slip easily? PCI ratings occupy a scale of 0-100; a score of 0–10 results in a “Failed” status, while a score of 86–100 merits  “Good” pavement condition. With regular analyses planned every three to five years, we aim to increase our PCI rating in the near future. A 2020 Pavement Management Report for the University of Illinois Urbana-Champaign campus streets, by Applied Pavement Technology, Inc., stated: 

“Overall, the 2020 area-weighted PCI of the university-maintained roadways is 65. Condition results from the previous [pavement] projects for the university can be compared to the results of this study to track how the pavement network is performing between PCI inspections. The overall area-weighted PCI was 59 in 2009, and 65 in 2016 and 2020 (excluding brick and gravel). It is interesting to note that the overall PCI remained unchanged from 2016 to 2020, despite annual spending of about $1.5 Million. …  The percent of pavement above a PCI of 70 has increased to 50 percent (it was 37 percent in 2009), while the percent of pavement with a PCI below 40 has remained near 25 percent for all inspection years.  Since the percent of pavement in the mid-range of the PCI scale (40 to 70) has decreased from 39 percent to 25 percent since 2009, it appears most of the major work that has occurred since 2009 has focused on improving pavements in this condition range.”[3]

Sustainable pavement materials

Sustainability and pavement condition go hand in hand; a strategy to improve both aspects of our university-owned road system is increasing the use of sustainable pavements. Implementing permeable pavements and biobinders will not only benefit the roads themselves but will also improve our flood and rainwater management infrastructure.

On a campus where more than 50% of the surface area is occupied by buildings or paved in roadways, walking paths, and parking lots, rainwater management poses a problem. While traditional pavement necessitates extensive gutter and drainage systems to manage water, permeable pavements (e.g., porous asphalt, which was used to pave parking lot C-8 in FY12[4]) allow rainwater to flow through the pavement and into a permeable gravel layer below, facilitating built-in water quality treatment and flood control. This process also keeps the pavement itself well-drained and in good condition, resulting in a higher PCI rating. Although installing permeable pavements can be costly, the reduced need for stormwater infrastructure (i.e. curbs, gutters, storm drains, etc.) roughly aligns long-term expenses with those of traditional pavement.

Biobinders are a second option for increasing the sustainability of our university-owned roads. In terms of concrete pavement composition, asphalt and cement are “binders,” the agents that bind rocks, gravel, and sand together to form the surfaces used on roads. While useful as bonding agents, asphalt and cement are synthetic materials derived from petroleum (which is itself derived from fossil fuels). As evidenced by the name, biobinders and bio-asphalt varieties are created from biomass materials. For example, research conducted through the Illinois Sustainable Technology Center (ISTC)[5] explored the practical potential of biobinders or bio-oil made from the pyrolysis of solid feedstock such as Miscanthus (an energy grass) or the hydrothermal liquefaction (HTL) of manure, food waste, algae, and other organic waste. 

Moving forward, we will investigate opportunities to integrate additional sustainable materials such as recycled or sustainably produced bricks and pavers, fly ash, and recycled glass into the composition of campus infrastructure.

[1] https://bit.ly/2BIAwUI
[2] https://bit.ly/39LuuiH 
[3] https://bit.ly/33zQgoP
[4] https://bit.ly/3ggqDfU
[5] https://bit.ly/39HDDsx