Material flow analysis of the residential building stock at the city of Rio de Janeiro
The extensive use of materials in building stocks contributes to the scarcity of natural resources and impacts from construction and demolition waste (CDW). Therefore, the concern with the efficient use of materials and CDW management made several countries conducted mapping, analysis and performance improvement in activities related to CDW using Material Flow Analysis (MFA). The city of Rio de Janeiro had a high urban development and building stock growth from the beginning of the last century, in which the amount of material consumed has not been documented. This study presents an MFA approach to assess the materials in-use and further flows of CDW from the residential building stock in the city of Rio de Janeiro. The material in-use was estimated from the extrapolation of the Material Intensities (MI) per different building types to the total constructed area in this city considering land occupation. The building types were modelled from the designs of typical buildings in Brazil. An analysis of urban development supported the estimation of buildings age and their remaining lifetime while national standards supported the time of replacement of building elements during the use phase. Results show that the stock in 2010 had about 78,828,770t of building material with MI between 2.58 and 0.74 t/m2; concrete and aggregates have the higher MI. The Use phase of the buildings will move about 9,807,690t of materials until 2090. These findings support further environmental impacts assessments and decision-making for planning CDW management and strategies for the efficient use of materials.