Abstract Manager

Research and observation indicate a continued change in global climate, which may influence pavement performance throughout their life cycles. To improve climate resiliency of pavement structures, highway agencies must monitor the trends of various climatic parameters that may impact pavement performance. Agencies should also develop and implement flexible strategies at all stages of a pavement's life cycle including design, construction and maintenance to mitigate current and future risks. Manitoba Transportation and Infrastructure (MTI) has identified several pavement related climatic parameters and recommended corresponding adaptation measures, as outlined in their 2024 Pavement Assessment and Design Manual (PADM). The objectives of this study are to develop trends and quantify changes over the next 30 years using historical climate data from Environment Canada records for last 30 years for selected climate zones in the province.

The pavement performance related climatic indices that are being collected and analyzed include annual and seasonal maximums/minimum temperatures and extremes, 7-day average maximum temperature, annual freeze/thaw cycles, mid-winter thawing durations, total annual and seasonal precipitations, extreme rainfalls, extended dry periods, low summer humidity, etc. Trend analyses are in progress to determine the amount of change, variability, and seasonality of those climate stressors that are most likely to contribute to pavement distress mechanisms and are to be considered in pavement design and management.

A preliminary analysis of the data from 1994 to 2025 for Winnipeg area indicates a warming trend in annual mean temperature, but the annual 7-day average maximum temperature shows a decreasing trend. The numbers of very hot and extremely hot days are increasing, reflecting warmer summers that raise risks of rutting, binder softening and surface oxidation, which may trigger the use of polymer modified stiffer asphalt binder. Higher winter minimums indicate a gradual reduction in extreme cold conditions, which may improve low temperature cracking performance of flexible pavements. Total annual precipitation shows a decreasing trend over time with more dry days. However, there is an increase of heavy or extreme rainfall events during the fall. While there is no considerable change of freeze-thaw cycles, but there is an increase in the number of mid-winter thaw days.

This paper will present the study methodology, completed analysis and findings with some recommended measures to make pavement structures resilient to changing climate. These information may offer other highway agencies some guidance in monitoring key climatic parameters and associated risks, and use them in their decision-making.