Dilation behaviour of lime mortars for restoration work: application to the compatibility of cracked stone reassembling

Research reveals that dilation, particularly thermal and hygric dilation, is a critical factor in the degradation of stones in semi-arid environments, such as those found at UNESCO World Heritage Sites like Volubilis (Morocco) and Djemila (Algeria). This study introduces a novel method to measure these dilations, highlighting their significance in assessing stone-mortar compatibility. Unlike traditional criteria for mortar selection—such as chemical composition, porosity, or mechanical strength—dilation behaviour provides deeper insight into how stones respond to environmental stresses, offering a more reliable basis for restoration techniques. The findings challenge conventional approaches, suggesting that mortars and grouts must be carefully matched to the dilation properties of cracked limestones to ensure long-term durability in harsh climates.

Mertz, J.-D., Guiavarc’h, M., & Pagnin, P. (2012). Dilation behaviour of lime mortars for restoration work: application to the compatibility of cracked stone reassembling. European Journal of Environmental and Civil Engineering, 16(5), 527–542. https://doi.org/10.1080/19648189.2012.668018