ORIGINAL PAPER Influence of Drying on the Stiffness and Strength of Cement-Stabilized Soils Alain Le Kouby . Antoine Guimond-Barrett . Philippe Reiffsteck . Anne Pantet Received: 7 April 2016 / Accepted: 30 October 2017 Ó Springer International Publishing AG, part of Springer Nature 2017 Abstract Nowadays, improving the strength and deformation properties of soft soils by deep soil mixing is a commonly used technique. There is also an increasing interest in the use of this technique for foundation/structural elements and excavation retain- ing walls applications. The compressive strength and elastic modulus of the soil mix material are key parameters in the design of these structures. However, there is very limited information available on the impact of exposure to air drying (in the case of retaining wall) on the strength and stiffness of cement stabilized soils. The aim of this study is to investigate the effects of different curing conditions (immersion in water, cycles of wetting and drying, continuous air drying) on the mechanical properties of soils treated with cement in the laboratory. Free–free resonance tests and unconfined compression tests were per- formed on specimens of silt and sand treated with blastfurnace slag cement. Strength increases more rapidly than stiffness between 7 and 30 days. The strength of stabilized soils submitted to cyclic wetting and drying before the cement hydration process is complete continues to increase. As long as the periods of drying do not induce microcracks, the stiffness of the treated soil specimens also increases with time. However, the stiffness is lower than for the specimens cured in water indicating a disruptive effect of the imposed wetting–drying cycles on stiffness. Continu- ous exposure to air drying inhibits strength develop- ment due to insufficient water for hydration. Significant stiffness decreases were observed on specimens of stabilized silt and are attributed to microcracking. Keywords Cement  Stabilized soils  Stiffness  Strength  Curing conditions  Wetting–drying List of symbols E 50 Secant deformation modulus at 50% of maximum stress (MPa) G 0 Small-strain shear modulus (MPa) G 0;7 days Initial small-strain shear modulus measured after 7 days (MPa) f s Resonant frequency for shear waves (Hz) L Length (m) A. Le Kouby (&)  P. Reiffsteck IFSTTAR, Universite´ Paris Est, Boulevard Newton, Champs sur Marne, 77447 Marne la Valle´e Cedex 2, France e-mail: alain.lekouby@ifsttar.fr P. Reiffsteck e-mail: philippe.reiffsteck@ifsttar.fr A. Guimond-Barrett SNCF Re´seau, 15 rue Jean-Philippe Rameau, 93212 La Plaine Saint Denis Cedex, France e-mail: antoine.guimond-barrett@reseau.sncf.fr A. Pantet LOMC, Universite´ du Havre, 53 rue Prony, 76058 Le Havre Cedex, France e-mail: anne.pantet@univ-lehavre.fr 123 Geotech Geol Eng DOI 10.1007/s10706-017-0401-y