Evaluation of the thermal behavior and physical–mechanical properties of different rocks from Limeira Intrusion (São Paulo State, Brazil)

Abstract

In this paper, different types of rocks exploited in a quarry located in the Limeira region (Sao Paulo State, Brazil) were studied to investigate its main petrographic characteristics, physical–mechanical (apparent specific weigh ρa, apparent porosity ηa, water absorption αa and uniaxial compressive strength UCS) and thermoanalytical properties, whose curves of each of the rocks were obtained from thermogravimetry (TG), differential thermal analysis and thermomechanical analysis (TMA). Four main petrographic types were evaluated: an aphanitic rock (APH), a diabase (DIA) and two monzodiorites with distinct granulations designated as MOMM and MONMC. In terms of mineralogical composition APH is the only rock that presents volcanic glass, while for the other rocks the main mineralogy was always associated with plagioclases, clinopyroxenes and opaque minerals. The results of the physical and mechanical characterization indicate the good aptitude of these materials to be used as aggregates in engineering works. The obtained values of apparent porosity (ηa) were less than 1% for all rocks. The value of resistance rates for all samples showed that the APH has the larger value, which is attributed to the grain size of the rock. The TG curves of each of the four samples contain small mass losses between the initial temperature and around 105 °C, which attributed to the water absorption. Besides, the APH sample had a mass loss attributed to the carbonate compound. The TMA curves showed that form DIA and MOMM are similar between them, while the APH differ from both. Further, the MONMC has not presented an appreciable thermal expansion.