Pavement design

Scope. Design of the pavement structure for urban and rural roads, accesses, car parks and yards. It covers the subgrade characterization (CBR and resilient modulus), the traffic study in 18-kip equivalent single axle loads and the definition of thicknesses, materials and construction specifications for each layer.

Design method. Flexible pavements are sized with the INVÍAS manuals and the 1993 AASHTO Guide, from the required structural number. Rigid pavements are sized with the INVÍAS and ICPC concrete pavement manual and the 1993 AASHTO Guide, including slab layout and the design of joints and dowels.

Review. When the traffic level warrants it, the design is reviewed with the AASHTO mechanistic-empirical procedure (MEPDG). The critical strains are computed with layered elastic theory: tension at the bottom of the asphalt layer and vertical compression at the top of the subgrade. They are then compared with the fatigue and rutting criteria.

Supplementary references. In cases not covered by the Colombian standards, such as bases with non-conventional materials or rehabilitations, the results are cross-checked with the Caltrans and FHWA guides. Materials are specified and tested under the INVÍAS General Specifications for Road Construction and Test Methods for Materials.

Research. The firm researches pavements with alternative materials at DIADICA Synthetic Core. The response of the proposed layer is first assessed by numerical modelling and compared with a conventional reference structure, before validation on test sections.