Influência da substituição do agregado miúdo natural por agregado reciclado fino em propriedades de argamassas e concretos




Construction and demolition waste (CDW) recycling has been a good alternative to reducing the impact caused by the consumption and high demand of raw materials for civil construction. In this sense, it has been tried to incorporate those wastes in the production of concrete and decrease strength mortar, what would increase its potential use. This study was developed aiming to assess the influence of the replacement of fine recycled aggregates for fine natural aggregates in properties of concretes and mortars. The study presents results of the physical characteristics of fine and coarse aggregates obtained from the manufacturing of CDW. The particles smaller than 0.15mm were analysed, concerning its pozzolanic reactivity, were analyzed in natural state and calcined to the temperature of 600C and 800C. Concretes and mortars were then produced with different replacement rates of fine natural aggregate (0%, 25%, 50%, 75%, 100%) for fine recycled aggregate as well as for coarse recycled aggregates, considering a water/cement ratio constant of 0.60 for the concretes and 0.66 for the mortars. The influence of the recycled aggregates was evaluated on properties of the concrete in fresh state (specific weight, workability, plastic shrinkage and hydration heat) and the hardened state (compressive strength and modulus of elasticity). For the case of mortars, they were evaluated in the fresh state (workability) and the hardened state (flexural strength, compressive strength and capillary absorption). The results show the influence of the fine fraction of CDW in the behaviors in the fresh state of the concretes and mortars, decreasing its workability, changing the concrete hydration kinetics and improveding the plastic shrinkage control. In the hardened state, was not evidenced an important better in the concrete and mortar strength with the process of calcination of the fine particles.


agregados (materiais de construçao) - reaproveitamento concreto - avaliação argamassa - avaliação engenharia civil

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