Upgrading, maintenance and rehabilitation of road infrastructure is expensive, especially in view of the growing scarcity and cost of suitable road building materials. In areas with high mica content and secondary minerals such as smectite in the natural materials, stabilisation with cement is not viable. The Council for Scientific and Industrial Research of South Africa has embarked on a research programme to evaluate the performance of substandard materials improved with anionic nanosilane modified bitumen emulsions for use in base and subbase layers. This work comprises laboratory testing as well as Accelerated Pavement Testing using the Heavy Vehicle Simulator (HVS). The results of a full-scale HVS test on a light pavement as well as initial analysis on a medium traffic road are discussed. It has been shown that stabilisation of available substandard materials using an anionic nano-silane modified bitumen emulsion compared with the standard approach of importing high quality crushed aggregate can lead to savings as high as 40%-50% for equivalent performance. In addition, there was also a significant reduction in construction effort and time.

The South African Institution of Civil Engineering (SAICE) Infrastructure Report Cards of 2006, 2011 and 2017 reported that much of the South African infrastructure is in a poor condition. To augment the recent 2017 Report Card, a survey was, for the first time, conducted amongst SAICE members to obtain their opinion on the condition of infrastructure (in terms of a grading), the trend of the condition over time, as well as the reasons for the individual's grading. The 669 respondents indicated that, apart from a few exceptions such as national airports and the Gautrain, much of the infrastructure is in a poor state, which is very similar to the results obtained from the SAICE Report Card process. The results were also analysed per province and indicated that, in the opinion of respondents, specific provinces in particular are struggling with poor infrastructure. The main reasons given for the poor infrastructure were a lack of maintenance, lack of institutional capability, lack of sufficient funding and over-loading of infrastructure. Keywords: infrastructure condition, SAICE Infrastructure Report Card, Infrastructure grading system

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