Mechanical properties and microstructural analysis of a concrete produced with aggregate from the Brazilian Amazon reg

ABSTRACT Due to the scarcity of aggregates in some regions of the Amazon, the present work has the objective of evaluating the properties of concretes produced with aggregate from the bed of the Oiapoque river. A comparative study was carried out comparing the characteristics of the large aggregates used in construction, especially the material found in the Oiapoque river bed in the city of Oiapoque, and the large aggregate from the metropolitan area of Belém. mechanical properties, performance tests and microstructure of concretes. The results showed that the use of the aggregate of arenite origin of the Oiapoque region showed no difference in the compressive strength and modulus of elasticity of the concretes in relation to the concrete produced with aggregate commercially available in the metropolitan area of Belém. the concrete as to the rate of absorption of chlorides over time and neither advance in the front of carbonation. The scanning electron microstructure of the concretes presented a dense microstructure, but usually found in cementitious matrix - based composites. These findings serve as empirical evidence for the validation of the use of an aggregate deposit in the Amazon Region, contributing to the development of infrastructure works in the region.摘要 鉴于亚马逊部分地区建筑骨料（aggregate）匮乏，本研究旨在评估采用奥亚波克河河床骨料制备的混凝土的各项性能。本研究开展对比试验，对比两种建筑用大型骨料的性能特征：一是奥亚波克市奥亚波克河河床骨料，二是贝伦都会区商用大型骨料，并针对制备得到的混凝土开展力学性能测试、耐久性能评估与微观结构分析。研究结果表明，采用奥亚波克地区石英砂岩（arenite）质骨料制备的混凝土，其抗压强度与弹性模量，与贝伦都会区商用骨料制备的混凝土相比无显著差异；同时，该混凝土的氯离子随时间吸收速率与碳化前沿推进速度均未表现出显著差异。扫描电子显微镜（scanning electron microscopy，SEM）观测结果显示，该混凝土的微观结构致密，与常规胶凝基复合材料的微观形貌特征一致。上述研究结果可为亚马逊地区该骨料矿场的应用可行性提供实证依据，有助于推动该地区基础设施工程的建设发展。