Probabilidad de mejora de las propiedades de materiales pétreos provenientes de 2 minas de la provincia del Azuay

Abstract

In the present research work, alternatives are studied to improve the geomechanical properties of stone materials from two mines in Azuay. The materials selected as the object of study come from the “Higuera” and “Llatcon” mines; With them, it is planned to meet the requirements corresponding to a base and improvement material, respectively, since their use is expected in future road projects within the province of Azuay. For the development of the project, a process of collecting information regarding previous tests of the material regarding physical and mechanical classification began, information that was provided by ASFALTAR EP. Characterization tests of the study materials were developed, which, in accordance with the previous tests provided, show that they do not comply with the technical specifications present in the Ecuadorian standard: "General specifications for the construction of roads and bridges" (MOP, 2002); regarding specific parameters such as: gradation, plasticity index, liquid limit and CBR support value, for which improvement proposals will be analyzed. Analyzing the deficiencies of the materials and based on the relevant literature, it was proposed to carry out an improvement of the Higuera material through mixtures with selected soil and stabilization with cement. The materials used to carry out the improvement with selected soil were: crushing powder, from the same quarry, and pozzolana from the Guachapala canton. For the stabilization of the granular material with cement, the reference values established in the ACI 230.1R-09 standard were considered regarding the recommended percentages of cement used in this type of stabilization, which are based on the AASHTO classification of the soil. Mixtures included in intervals were made, from which an optimal percentage of cement applicable on site was obtained, which complies with the specifications established for granular bases stabilized with cement present in the Ecuadorian regulations (MOP, 2002). For the material from the Llatcon mine, an improvement of the material was established through the soil-cement mixture. The design of the mixture was carried out through a process similar to that developed with the material from the Higuera mine, in the same way an optimal percentage of cement applicable to the work was obtained that complies with the specifications established for soil-cement mixtures, present in the Ecuadorian regulations (MOP, 2002). When performing a comparative analysis with respect to the regulations, favorable results were obtained by mixing the material from the Higuera mine with pozzolana and road cement; since with these processes it was possible to raise the geomechanical properties of the material in such a way that the parameters established in the regulations regarding granular bases and granular bases stabilized with cement were met. Similarly, the soil-cement mixture led the material from the Llatcon mine to meet the necessary parameters to be considered for use as soil-cement. A feasibility analysis was also carried out, comparing the different mixtures and the influence they could have on the viability of a particular work. It was also demonstrated through the theory of equivalent layers that the improvement of the material translates into a reduction in thickness; This is demonstrated by way of example, analyzing a 20 cm thick layer of material from the Llatcon mine; which, when stabilized with soil-cement, is equivalent to a layer of 9 cm. Finally, a process of characterization and comparison with the regulations for materials from the "Santa Isabel" mine was carried out and theoretical improvements based on the experiences acquired during the development of this project are proposed.