Development and Implementation of Ultrathin Concrete Road Technology for Suburban Streets in South Africa

Abstract

There is a significant need in South Africa for the upgrading of suburban streets with a solution that performs well, is cost-effective, and requires minimal maintenance. There is also a need for job creation in road construction, using local labor when possible. The ultrathin reinforced concrete pavement (UTRCP) technology, one such solution, was developed by the Council for Scientific and Industrial Research in South Africa and has been implemented in a number of projects. The technology was developed for suburban streets and roads carrying fewer than 2,500 vehicles/day and is constructed with labor using light plant. UTRCP consists of a lightly reinforced, 50-mm-thick, 30-MPa concrete layer that is generally constructed on shaped and compacted in situ material; modification may be required if the in situ material has a high plasticity index. Experimental work was conducted by testing trial sections of UTRCP supported by various subbase layers. This included static testing, rolling wheel load testing with a heavy vehicle simulator, and evaluation of the performance of trial sections under normal traffic. The results of the experimental work and the subsequent proposed structural designs used in implementation projects are described. The technology has been implemented in various projects in suburban townships in South Africa in the Gauteng Province. The practical lessons learned from these projects are described. Lastly, criteria for the subbase design of pavement structures containing the UTRCP layer are proposed, and further work is suggested.