Geological, petrographic and technical characterization of the quartzite sandstones of the Los Ranqueles Formation for its application in construction, south of Córdoba, Argentina

Abstract

A geological, petrographic and technical characterization of the sedimentary rocks of the Los Ranqueles formation, located in Sampacho, southern Córdoba province, is exposed. The Los Ranqueles formation is constituted by fine- to medium-grained quartz sandstones, with intercalations of fine-grained conglomerates and siltstones. Petrographic and physico-mechanical features were evaluated in two main lithological types, quartz arenite and quartz wacke. Standardized physical tests (Los Angeles coefficient, specific weight, absorption, laxity, elongation), petrography (texture and mineral mode) and evaluation of deleterious expansion of concrete due to alkali-silica reaction (ASR) were carried out. This sandstones present high absorption (> 2.0%), low specific density (< 2.58) and Los Angeles coefficient from 30 to 42 %. The optimal uses for each lithology were defined according to the current regulations. The strength of the quartz sandstones is mainly controlled by the porosity, the degree of cementation and the mineralogy of the cement. Lower Los Angeles coefficients and absorption values were obtained in those rocks that have closer packing, greater contact between grains, greater degree of cementation with more resistant minerals and lower porosity. The studied rocks could be considered in new projects of civil works for sub-bases and granular bases, low-traffic pavements, concretes not subject to abrasion, sub-ballast and hydraulic containment structures. This work represents a contribution to the knowledge of this formation and reinforces the importance of geological and petrographic studies in the exploitation of aggregates for construction.