37º IAHS World Congress on Housing: - Universidad de Cantabria

XXXVII <strong>IAHS</strong><strong>World</strong> <strong>Congress</strong> on HousingOctober 26 – 29, 2010, Santander, SpainCODE: 109SUSTAINABLE CONCRETE ROOF TILES CONTAININGRECYCLED GLASSPaulo H. R. Borges 1 , Túlio H. Panzera 2 , Fábio P. Cota 2 , Antonio L. H. Sabariz 21 Department of Civil EngineeringFederal Centre for Technological Education of Minas Gerais, CEFET-MG, Brazilemail: pborges@civil.cefetmg.br2 Department of Mechanical EngineeringFederal University of São João del Rei, UFSJ, BrazilKey words: recycled glass, sustainability, concrete durabilityAbstractThe final disposal route of post-consumer recycled glass (RG) is a common issue for manymunicipalities worldwide. Approximately 1 million tons of glassware is produced per year inBrazil, only 47% of which are currently recycled. The idea of incorporating RG as aggregatefor concrete emerged in the 60´s motivated by some of the advantages of glass, i.e. low waterabsorption, high abrasion and durability, aesthetic potential among others. However, theinitial researches have shown that concretes containing RG exhibited marked strengthregression and excessive expansion due to alkali-aggregate reaction (ASR), which limitedfurther research. The topic emerged again in the 90´s, imposed by the sustainability issues.Moreover, new studies aimed to determine the conditions at which ASR does not occur, aswell as the influence of RG on the physical properties of concrete. Despite some literature onthe use of RG into concrete, its application for making concrete roof tiles is still notdocumented. The incorporation of RG into those products, if feasible, may create asustainable material for construction by reducing the land-filling of RG in municipalities nearthe concrete tile plants. This paper investigates the use RG as replacement of 7.5% and 15%silica aggregate in concrete roof tiles. Three grading of RG were studied, i.e. particles retainedbetween 4.76 – 1.68 mm, 1.68 – 0.84 mm and 0.84 – 0.30 mm sieves. Metakaolin (MK) hasbeen chosen to replace 7.5% and 15% wt. cement and potentially suppress ASR. The physicalproperties assessed were dry bulk density, compressive strength and modulus of elasticity; theengineering properties determined were apparent porosity and oxygen permeability. Resultsshowed that the use of 7.5% RG in combination with 7.5% MK provided equivalentperformance to reference semi-dry pre-cast concrete and, therefore, permit a new route ofdisposal for the RG.37º <strong>IAHS</strong> <strong>World</strong> <strong>Congress</strong> On Housing Science 64