No abstract

Geopolymeric materials have recently been considered a revolutionary class of materials, due to the diversity of applications where they can be used, this derived from their good mechanical resistance, thermochemical stability and good fire resistance. From 1970 to the present, a notable increase has been observed in the number of scientific publications dealing with the synthesis and applications of geopolymeric materials with industrial application. Several publications have reported geopolymers as alternative materials to Portland cement, which will allow having a green construction industry in the coming years. The elaboration of geopolymeric materials is relatively simple, beginning with the identification of a source rich in amorphous aluminosilicates and a hardening compound (mainly alkaline in nature) which are properly mixed until a homogeneous and workable paste is obtained, then can harden at room temperature and acquire good mechanical resistance in a few hours. On the other hand, mining in Peru is one of the most important industries due to its contribution to the economic development of the country. However, mining is also one of the industries with the greatest negative impact on the environment, mainly due to the enormous amount of inorganic waste that it generates and which is currently accumulated without any prospect of recycling or reuse. Therefore, this research was conducted to elaborate concretes from mining tailings and to evaluate their mechanical behavior in creep (between 500 and 600 ºC). The results obtained allow us to propose the use of mining tailings for the elaboration of geopolymeric thermal barriers that work in conditions of intermediate temperatures, up to 600 ºC.

Composites are a group of materials that for several years have been attracting the attention of the international scientific community, these materials combine the properties of two or more types of materials to make a new one with better properties than those of their precursors, without them react chemically. This paper presents a study about the manufacture of new composite materials of wood sawdust dust, obtained by hot pressing at 180 ° C and reinforced with natural fibers from Peru (alpaca wool and ichu). The mean apparent density found for all the compounds was around 1.21 g/cm3 and the values of maximum stress and modulus of elasticity reported were in the range of 77 - 95 MPa and 3.5 - 4.1 GPa, respectively. The microstructures found for all the compounds consist of a continuous and homogeneous matrix of lignin (from wood) with short fibers of alpaca and ichu wool, dispersed in the continuous matrix.

Reinforced geopolymeric mortars were obtained by mixing mine tailing, fine sand, alpaca wool fibers ( in variable amounts) sodium hydroxide and potable water, it was possible to verify the effect of the addition of alpaca wool on the mechanical behavior in uniaxial compression of the mortars studied. The mechanical data found revealed a systematic decrease in the maximum stress as the volume of wool added in the mortar mixtures manufactured increased. On the other hand, a higher degree of deformation was verified in mixtures with a greater volume of added fibers, reaching deformation values of up to 5%. The maximum strength values were in the range of 4 to 21 MPa for samples with 8 and 0 Vol. % of added fibers, respectively. Among the microstructural characteristics of the mortars studied, a continuous binder phase corresponding to the geopolymer could be appreciated, with sand particles and wool fibers dispersed within the binder phase. The real density and average porosity of the reinforced mortars were 2.65 g/cm3 and 32%, respectively.

This work presents the results of the thermomechanical evaluation of geopolymeric concrete fabricated from mining tailings, rice husk ash and fine sand. Ten types of geopolymeric concrete were studied and the relationship between the initial volumetric concentrations of the components in the mixtures and the maximum resistance in uniaxial compression under conditions of variable temperature (between ambient and 600 °C) was analyzed. The results revealed that increases in the concentration of mining tailings and fine sand lead to an increase in the value of the maximum mechanical resistance, in contrast, the increase in the concentration of rice husk ash led to a reduction in the value of the maximum mechanical resistance. Furthermore, increases in test temperature, up to 500 °C, led to systematic increases in maximum mechanical strength. Finally, the geopolymeric concretes presented a brittle-ductile transition between 500 and 600 °C showing only a ductile behavior when tested at 600 °C and only brittle up to test temperatures of 500 °C.