Mechanical Performance Improvement of a Gypsum Tuff with a Sodium Hydroxide Treatment

Abstract

         This work is part of the valorization of local Saharan materials intended for road construction. It aims to improve the mechanical performance, particularly the resistance to simple compression, of a tuff encrustation from the Ouargla region, initially possessing poor mechanical properties. This improvement is achieved through chemical treatment with a sodium hydroxide solution at different pH levels. The obtained results demonstrate that the chemical treatment of tuffs with an alkaline solution of sodium hydroxide improve their resistance to simple compression, and the concentration of the solution and the conservation mode of the specimens have an effect on this improvement. The maximum value of resistance (1.18 MPa) was achieved for specimens treated with a sodium hydroxide solution at a concentration of 2.4×10^-1 (mole/l) with a pH of 13.38 and conserved under laboratory conditions (mode1).