Field strength development of repaired pavement using the recycling technique

The pavement recycling technique is a way to effectively repair damaged pavements. In this study, statistical analysis shows that the field strength is significantly lower than the laboratory strength. The mixing process used in the pavement recycling technique does not significantly affect the field strength reduction, as indicated by the small variation of the field hand-compacted strength (q(ufh)) and the laboratory strength (q(u1)). The curing conditions do significantly control the field strength development. A factor of safety of 2.0 is recommended for design. The strength development mainly depends on the soil-water/cement ratio (w/C) and curing time regardless of the level of compaction energy. A general strength development model as a function of w/C and curing time is introduced. Only two laboratory strength data from the specimens cured at two different curing times are required in the proposed model. A high accuracy of the strength prediction is reported. This proposed model is a very powerful tool that determines the strength development of cement-stabilized coarse-grained soil after 7 days of curing. It can also be used to determine the correct quantity of cement to be stabilized for different field mixing water contents, compaction energies and curing times.