The Detachment Physical Weathering Form Group Affecting Stone Building Materials at The Archaeological Site of Sabratha, Northwest Libya

Abstract

The archaeological Sabratha City is a UNESCO World Heritage site located on the Mediterranean Sea coast west of the Capital City of Tripoli north of Libya. Like many other archaeological cities in the world, Sabratha monuments have been built using naturally existing stones which according to the rules of nature are subjected to continuous weathering processes and become damaged to varied degrees. The range of extension as well as the type of stone damage is dependent on the reacting stone materials with the natural weathering processes. From an important point of view, the preservation of stone monuments now has attained the care of the government institutions who are in concern. The present paper discusses the main physical weathering forms belonging to the weathering form group-3 "the detachment group" which has been established by (Fitzner, and Heinrichs, 2002, 2004). The methodology of this research will be based on applying certain forms invented by Fitzner and Heinrichs that serve to estimate every damage of weathering forms affecting the monuments of Sabratha City. A number of nine main weathering forms of the detachment group including about fifteen individual weathering forms were found to affect the whole monuments of the city with damage intensity degrees varied between non-visible damage and moderate damage (0 degrees and 3 degrees). To make it easy for observations, fifteen contour maps were drowning for each individual weathering form showing the damage intensity degree and distribution. To summarize the overall picture of the weathering form damages, linear and progressive damage indices were found and mapped. Diurnal and seasonal temperature variations; relative humidity fluctuations; salt crystallization; moisture and or water content are factors expected to produce such weathering damages. As a recommendation, the authorities in response are invited to take this matter seriously and should act to protect the built heritage of Sabratha City.