Concrete Subbases For Flexible Pavements (Nov 1978)

Concrete is being increasingly used in the Sydney area to provide a sub-base for flexible road pavements. Typically, the pavement comprises 150 mm of plain concrete sub-base beneath a conventional roadbase and a surfacing of asphaltic concrete. Figure 2 shows the general form of pavement construction. The concrete sub-base provides two major benefits. Structurally, the stiff sub-base layer is very efficient in reducing pavement deflection, tensile strain in the bituminous surfacing, and total pavement depth. Such structural advantages were demonstrated in a Paper f1 7 presented at the 1976 AR RB Conference which was reviewed in a previous Road Note!2 ! . The second major benefit is that the concrete subbase provides an excellent working platform upon which the base and surfacing can be quickly constructed, allowing the pavement to be constructed with minimum delay. Benkel man Beam deflection criteria and compaction of superimposed layers can be readily achieved on the concrete subbase.