PSI - Issue 5

Aalil Issam et al. / Procedia Structural Integrity 5 (2017) 1123–1128 Aalil Issam/ Structural Integrity Procedia 00 (2017) 000 – 000

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the UNESCO listed Volubilis as a World Heritage Site, for being "an exceptionally well preserved example of a large Roman colonial town on the fringes of the Empire" (Kingdom of Morocco 1996). Most of the monuments of Volubilis were built using a beige-yellowish calcarenite limestone called “molassa”. The site of Volubilis has undergone various disorders over the years, generating alterations in materials as well as in the structure of buildings. In a previous study (Aalil et al. 2016), four main deterioration patterns were shown to be affecting the calcarenite stone: lichen colonization, sanding, scaling and alveolization. The last three deterioration patterns are damaging as they induce detachment and loss of calcarenite material while lichens discolor it.

Nomenclature ρb

Bulk density Matrix density

ρm

P

Porosity

A Capillary absorption coefficient Scap Capillary saturation coefficient CS Compressive strength V P wave velocity E dynamic E-Modulus L Lightness a Red/green coordinate b Yellow/blue coordinate

Fig. 1. The western part of the Volubilis site.

Diagnostic studies carried out on the site showed that there are many collapsed walls due to the low quality of mortars, composed of lime, mud and lime-mud as binder (fig.2a). Some recent grey mortars with high hardness were also observed. According to the conservation direction of the site, Portland cement was used to improve the strength of lime mortars (fig.2b). Previous analyses confirmed that these grey mortars and their neighbouring deteriorated stones contain gypsum (Aalil et al. 2016). The present study was therefore performed to characterize the fresh calcarenite stone and to propose a compatible pozzolanic mortar recipe for future interventions.