Roller-Compacted Concrete as a Road Building Material in South Africa

Roller-compacted concrete (ReC) offers a solution to the vast number of good quality lowvolume roads which will have to be provided in the near future to accommodate South Africa's rapidly expanding rural road needs. The research effort presented in this paper involved a laboratory study and the construction and accelerated testing of a trial section in order to investigate the use of Ree for roadbuilding purposes. The laboratory study allowed for the determination of various engineering properties for different mix proportions and aggregate types. Among the aspects investigated were the effects of varying the cementitious/water (c' /w) ratio, the percentage fly ash substitution and curing time. A test section was also constructed and subjected to accelerated testing using the Heavy Vehicle Simulator (RVS). Encouraging results were obtained, indicating enormous potential for the use of Ree pavements in low volume roads. The section withstood in excess of 5 million equivalent 80 kN axle loads without any signs of distress. Results and recommendations emanating from this laboratory study and trial section have been implemented with great success in the construction of further experimental pavements.