Environmental and Economic Analysis of Using Recycled Concrete Aggregates in Composite Steel-Concrete Slabs

The needs to reduce the environmental impact of concrete buildings is gaining more importance. In particular the consumption of natural aggregates requires the opening of new quarries and represent an environmental problem. A good solution for the latter is the use of concrete recycled aggregates obtained from construction and demolition waste. Composite slabs offer many advantages over traditional reinforced concrete slabs, including increased strength and stiffness, improved fire resistance, faster and easier installation, and greater environmental friendliness. Thus, the use of composite slabs with concrete recycled aggregates represents a promising strategy to reduce the constructions environmental impact. The aim of this paper is to analyze the environmental impact and the economic aspects of the use of concrete with recycled aggregates for composite steel-concrete slabs with variable spans from 2.5 m up to 8 m and different service loads. In particular, the amount of carbon dioxide saved by replacing natural aggregates with recycled ones has been evaluated considering 30%, 50%, up to the total of 100% replacement percentages. In addition, the construction costs have been estimated, always comparing the use of ordinary concrete with natural aggregates and the use of recycled ones. Results show that using recycled aggregates reduces the environmental impact of composite slabs with a very little economic cost reduction.