Smit, Michelle ARust, FCZamara, ZMazurowski, PKawalec, J2025-12-032025-12-032025-091029-84361477-268Xhttps://doi.org/10.1080/10298436.2025.2542872http://hdl.handle.net/10204/14480Road construction costs are high partly due to the scarcity and cost of good quality building materials. The inclusion of geosynthetics in flexible pavement structures has been shown to improve pavement performance. The study indicated the potential benefit of increasing the life of the pavement by adding a multi-shape geogrid layer to a cement-treated subbase. APT testing was conducted using the Heavy Vehicle Simulator (HVS) of the Council for Scientific and Industrial Research (CSIR) in South Africa. When the rutting data, deflection data and the stiffnesses back-calculated from FWD data are considered, it is evident that the inclusion of the geogrid into the cement-treated layer was beneficial and could increase the life of the pavement significantly. The addition of the geogrid to the structure led to an approximate 5% increase in the construction cost. This is negligible in comparison to the significant increase in pavement life. However, the results are valid for a relatively strong (10–30 million ESAL) design. Further work should include the use of the geogrid in a cement-treated base in a weaker pavement where the benefit could potentially be higher.AbstractenMulti-Shaped geogridAccelerated pavement testingRoad construction costsHeavy Vehicle SimulatorHVSArticleN/A