_________________________________ University of Liège, Civil and Mechanical Engineering Institute (B 52/3). Chemin des Chevreuils, 1, B - 4000 LIEGE, Belgium – Phone: 32.4.366.93.50 – Fax: 32.4.366.92.38 – Email: [email protected] Effects of the presence of free lime nodules into concrete: 1 experimentation and modelling 2 3 Luc COURARD*, Hervé DEGEE, Anne DARIMONT 4 University of Liege, Department of Architecture, Geology, Environment and Constructions, 5 Belgium 6 7 8 ABSTRACT 9 When nodules of lime are embedded into concrete, the expansion 10 accompanying the transformation of CaO into Ca(OH) 2 induces stresses and 11 strains in both the lime nodule and in the concrete matrix. The concrete cover 12 thickness, the diameter and the shape of the lime nodule as well as the 13 mechanical characteristics of concrete and lime are the key parameters 14 influencing the development of internal pressure and hence controlling the risk 15 of cracking or pop-out. In order to study the effect of lime into cementitious 16 concretes, laboratory investigations and modelling have been performed and 17 show that the minimum cover thickness necessary to avoid the development of 18 the pop-out phenomenon is estimated of the order of half the diameter of the 19 inclusion. This is coming from the observation that expansion happens inside 20 the porosity of the hydrated lime Ca(OH) 2 : ESEM and DRX analysis confirm 21 the effect of confinement in the development of crystals. 22 23
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