Mechanical Evaluation of Geopolymer Mortars Derived from Gold Mining Tailings under Differents Atmospheres

Abstract

In this work, geopolymeric mortars made from formal and informal gold mining tailings (Peru) were studied in order to analyze their durability and mechanical resistance in compression. The manufactured mortars were subjected to uniaxial compression tests in four atmosphere conditions: dry air (0% humidity), saline air (5% with sodium cholride), humid air (99% relative humidity) and normal air (with relative humidity at 25%). During the compression tests, the thermoresistance at room temperature (between 11), 200 °C and 500 °C were also evaluated. The results obtained were contrasted with the mechanical resistance of mortars made with conventional cement (Control). The real density and porosity of the different mortars studied were also evaluated, finding real density and porosity values of 2.42 g/cm3 and 19%, 2.62 g/cm3 and 32%; and 2.71 g/cm3 and 36% for conventional cement mortars (Control), tailings geopolymeric mortars from informal mining (GI) and tailings geopolymeric mortars from formal mining (GF), respectively. The mechanical results obtained show average values of maximum compressive strength of 86 MPa, 23 MPa and 19 MPa for Control mortars, GI mortars and GF mortars, respectively. It was also possible to appreciate that the geopolymeric mortars presented cracks, superficial efflorescence, affecting the mechanical resistance in humid and saline atmosphere conditions. The simulated climatic conditions, in which it could have a better mechanical behavior, is a normal atmosphere and dry air. Regarding the evaluation of thermoresistance, they were at a temperature of 500°C, which presented greater mechanical resistance.