Decreasing salt susceptibility index of nummulitic limestone using three resins applied in different ratios and concentrations

摘要

Salt weathering is one of the most aggressive worldwide weathering processes severely affecting natural and artificial materials to unlimited weathering grades. This impact is highly considered for the highly ranked archeological sites. So, this paper aims to examine the durability of the huge quarries of the Eocene nummulitic limestone that had been widely used for construction and/or carving of the Pharaonic archeological sites in Egypt, e.g., the Giza Pyramids and the Great Sphinx. The durability had been examined for this limestone before and after applying three resins prepared in single or combined states and at variable limits of concentration. These resins are namely ethyl silicate, Premal-AC33, and Paraloid 80. Petrographic, mineralogical, physical, and mechanical properties and durability investigations had been conducted for this limestone before treatment with such resins. Treatment has been conducted through two regimes, namely repeated brushing and total immersion using each resin at each level of concentration. Examining samples' surface color after treatment and resin's penetration depth, as well as rock's geotechnical properties', limits using ultrasonic waves, and sample's salt susceptibility index (SSI) using Mercury intrusion porosimetry (MIP) has been considered for each resin at each level of concentration. The data had been discussed indicating that Paraloid B-80 used in a single state dissolved in 300ml acetone or in combination with ethyl silicate dissolved in ethyl alcohol are the best for increasing durability of such nummulitic limestone.