Linking small-strain stiffness to development of chemical reactions in lime-treated soils

In the context of lime stabilization, this note shows how the development of soil–lime reactions can be linked to the variation of small shear stiffness with time. To determine the evolution of small-strain stiffness, the shear wave velocity was measured by means of bender elements (BE) on a compacted clayey soil treated with 3% quicklime, starting form 2 h after compaction until 98 days of curing. Different methods of signal interpretation were applied with the purpose of highlighting how the peculiarity of lime treated soils affects BE testing results and to provide practical indications for optimizing similar testing on lime-treated soils. The results showed that lime treatment and compaction affect the waveform of the received signal and that measurements should span across a wide range of input frequencies in order to identify an optimal waveform. The small strain shear modulus was found to increase with curing time with a trend that can be related to that of soil–lime chemical reactions, thus representing a promising parameter to monitor the development of soil–lime reactions.