GROUND STABILIZATION OF THE MR348 – MORRISON ROAD – GLENTANA – SOUTH AFRICA

Ground stabilization techniques are breaking through South African pavements as cost-effective solutions achieving design performance with shallower layerworks, higher design traffic or using poor material. Morrison Road near Glentana is the first project in South Africa where ground stabilization was used increasing the support over a very soft subgrade for a 3 million E80 pavement. Original design was based on the South African Pavement Design Method (SAPDM); while the ground stabilization was based on the AASHSTO including the layer coefficient ratio (LCR). Two layer of bidirectional extruded geogrids were placed in the subbase and base achieving a reduction of the pavement from 1.2m to 0.7m maintaining the same traffic loading. The installation of the geogrids had required training of the contractor to ensure CQA achieved by extensive site supervision and modification to current South African construction methodology to ensure the geogrids would have not been damaged during installation.