Flexible Concrete Pavements

The strength of flexible pavements is more or less at the limit of design, and only minor improvements in allowable contact pressure can be expected. Major increases in vehicle weight on flexible pavements is only possible by increasing the number of axles or by increasing any extra contact area (larger tyres, more wheels) requiring an extra depth of flexible construction. Tli current stronyth of rigid pavements r.niild he improved by increasing the thickness of the concrete layer. However, most of the stresses in concrete pavements are internally generated by volume changes of the concrete and ot the soil below, ratliei than by traffio. The increase of thA qlah thickness results very often in an increase of the stresses, requiring either frequent expansion joints or design changes. A now technique has been developed which combines the high load capacity of concrete and the long term flexibility of bituminous pavements. This may prove an economic reconstruction method for existing roads to carry heavier axle loads without significantly increasing the slab thickness, as compared to conventional methods.