Ultra thin reinforced concrete pavements : experiences encountered during the construction of two roads

Abstract

Paper presented at the 28th Annual Southern African Transport Conference 6 - 9 July 2009 "Sustainable Transport", CSIR International Convention Centre, Pretoria, South Africa.

During the beginning of 2002, a section of mesh reinforced concrete pavement 50mm thick was constructed as part of a thin concrete road experiment to a quarry at Roodekrans in the vicinity of Krugersdorp. As a result of the performance of this 50mm section of ultra-thin reinforced concrete pavement (UTRCP) the CSlR was appointed by the Eastern Cape Roads and Transport to apply the concept to the construction of a 2,4 kilometre access road to a quarry in the vicinity of Mthatha. The road would also benefit communities along the road, not only by providing improved access and reducing the risk of accidents but also by improving the quality of life by reducing the dust created by the trucks hauling aggregate along the road.Towards the latter half of 2007, as part of its 20T programme (Twenty identified Townships Roads Upgrading Programme), which also targeted the implementation of innovative technologies and the creation of employment opportunities in the construction of the roads, it was decided by the Gauteng Department of Public Transport, Roads and Works to pilot the UTRCP concept in this programme. CSlR was appointed to provide specialist support to the Department relating to the construction of ultra-thin reinforced concrete pavements.It is the intention of this paper to share the findings and experiences encountered and lessons learnt in the construction of these two roads. The paper also touches briefly on the preliminary findings of experimental work that the CSlR has been carrying out in collaboration with the University of Pretoria on comparison of the performance of concrete using reconstituted bottom dump ash as aggregate and conventional crushed stone aggregate in the construction of ultra-thin reinforced concrete pavements.