Assessment of the effects of climate change on the performance of pavement subgrade

This research investigated the effects of future climate change on pavement life in South Africa by simulating prolonged moisture presence in the pavement subgrade. The study was conducted on roads P435 and P443 within uMkhanyakude District Municipality. Climatic data were collected from the Council for Scientific and Industrial Research (CSIR) and Climate Systems Analysis Group (CSAG) from 1940 to 2001 and simulated from 2012 to 2062. Sampling was done using the standard procedure described in Technical Methods for Highways (TMH) 5 and soil laboratory tests carried out according to TMH 1. Results of laboratory tests classified the materials as G10 based on their California bearing ratio (CBR) and plasticity index (PI). Relative compaction of 91.4 and 94.3% were obtained from the CBR test on the subgrade layers of roads P435 and P443 respectively. The research showed that 50 years into the future will bring a climate change signal that will be minimal in terms of precipitation. However, natural weather variability threatens to be the dominant signal. The pavement life has been shown to decrease in a way that would threaten the road category and design reliability.