Characterization of Limeira intrusion stones for aggregate use in engineering applications

Major exploitation phases in quarries involve stone fragmentation by blasting and crushing. Considering the nature of stone aggregates and their applications in engineering works, technological characterizations are fundamental to the adequate selection of these stone products. The present work aimed to characterize stones with different compositional, structural, and textural aspects in a quarry belonging to the Limeira Intrusion, state of São Paulo, Brazil. Distinct samples of aphanitic stone (basalt), diabase, and two monzodiorites were collected. Routine technological tests were performed to qualify the stone aggregates, aiming at their use in Portland cement concrete and asphalt pavements, as well as to meet the greater commercial demands for coarse aggregate produced by the local mineral industry and railway ballast. The values obtained in the physical-mechanical tests evidence no limitations to the use of these types of stone in engineering works. Alterability was low, which highlights the suitability of the two varieties of stones predominantly found in the deposit (diabase and medium-grained monzodiorite) for use as railway ballast. Growing demand for crushed stone considering the implementation of important transport infrastructure works in the region. The fines generated in diametral compression tests with fast loading rates were also quantitatively analyzed. An increase in fines was observed related to higher strengths. This behavior is corroborated by the literature and also by field observations. Some restrictions were detected in the reaction tests with binders. In the adhesiveness test of coarse aggregate to bituminous coating, all the stones presented unsatisfactory results, although the basalt presented much less detachment from the asphalt binder. The alkali-aggregate reactivity tests proved that only one monzodiorite is non-reactive, and the other lithotypes have an R1 reactivity level. These results are related to the variation in petrographic characteristics. Therefore, technological studies associated with the geological context in quarries with some lateral and vertical heterogeneity are essential to assist in the selection of stony materials most suitable for more specific commercial demands.