Shrinkage cracking is a major issue associated with the use of chemically stabilised (cemented) materials in road pavement construction. In stabilisation of road pavements in-situ, this issue is further complicated because the stabilised material can be a mixture of several materials comprising aggregates, stabilisers and pozzolans. The current paper suggests that it is prudent to approach this issue by making use of the knowledge gathered on similar materials from other fields such as concrete and geotechnology. Accordingly, the paper presents a synthesis of the state-of-the-knowledge of shrinkage behaviour of cemented materials when they undergo moisture loss or drying. Based on this synthesis, it was established that the shrinkage strain or cracking potential due to drying shrinkage is a function of five major factors, namely, environmental, material, time, specimen size and boundary conditions. Theoretical linkages of these factors to shrinkage strain or cracking potential were briefly presented. These theoretical linkages include moisture loss under suction, vapour pressure and temperature gradients subjected to environmental conditions, and the resulting shrinkage and tensile stress development due to material displacements subject to boundary restraints. On this basis, a research approach is presented to address the shrinkage cracking problem as applicable to road pavements. This approach involves the development of rigorous theoretical studies and the development of simplified formulae or charts for practical use, similar to those developed for concrete. (a)
Samenvatting