Study of solidification of menthol for the applications in temporary consolidation of cultural heritage

Menthol has been employed recently as important temporary consolidant for conservation of cultural heritages. In this paper, a phase field solidification model is proposed and numerical simulations are conducted to investigate the solidification mechanism of menthol. Simulations provide not only the phase transition of menthol during solidification in consistent with experiment, but also how solidification reaction and evolution of heat are mutually interacted. Solidification leads to liberation of latent heat, contributes to the high temperature in un-solidified core and in turn retards solidification. In addition, size effects on solidification quality and mechanical strength are investigated. During solidification, tensile stresses affect solidification and lead to micro defects which are described using relaxation strain in this manuscript, result in size dependent volumetric contraction as well as residual stress after solidification. Operating solidification in smaller size geometries would help lower down the internal stresses and relaxation strain, resulting in denser products of higher mechanical strength. Therefore, multistep casting procedure is suggested rather than one step casting in real consolidations using menthol.