Abstract:
The porosity of construction and demolition waste (CDW) recycled aggregates can be determined by specific gravities under two conditions: a) apparent, which includes volume of pores of particles, and b) real, which includes only volume of solids. These physical properties can be determined in a fast way by powder-gas picnometry. Time required fpr characterization can be reduced from 30h to 7h. This article compares CDW recycled aggregate physical properties determined both powder-gas picnometry. Time required for characterization can be reduced from 30h to 7h. This article compares CDW recycled aggregate physical properties determined both powder-gas picnometry and traditional methods, for large range particles porosity. CDW recycled aggregates samples were separated by size and density intervals, being further characterized for both methods (Helium and Geopyc picnometries and buoyancy method). In conclusion, there are evidences that the proposed method is more precise and reproductive than the standardized one. Apparent volume determined in water can be overestimated due to difficulty in water removing on surface aggregates. Solid volume determined in water also is overestimated because of difficulty accessing pores by water under atmospheric pressure. As a result, porosity was underestimated.
Reference:
ÂNGULO, Sérgio Cirelli; SILVA, Raphael B. da; OLIVEIRA, Vinicius L. de; ULSEN, Carina. Caracterização das propriedades físicas dos agregados graúdos de RCD reciclados por picnometria de pó e gás. In: CONGRESSO BRASILEIRO DO CONCRETO, 54., 2012, Maceió. Anais… São Paulo: IBRACON, 2012. 12 p.
The porosity of construction and demolition waste (CDW) recycled aggregates can be determined by specific gravities under two conditions: a) apparent, which includes volume of pores of particles, and b) real, which includes only volume of solids. These physical properties can be determined in a fast way by powder-gas picnometry. Time required fpr characterization can be reduced from 30h to 7h. This article compares CDW recycled aggregate physical properties determined both powder-gas picnometry. Time required for characterization can be reduced from 30h to 7h. This article compares CDW recycled aggregate physical properties determined both powder-gas picnometry and traditional methods, for large range particles porosity. CDW recycled aggregates samples were separated by size and density intervals, being further characterized for both methods (Helium and Geopyc picnometries and buoyancy method). In conclusion, there are evidences that the proposed method is more precise and reproductive than the standardized one. Apparent volume determined in water can be overestimated due to difficulty in water removing on surface aggregates. Solid volume determined in water also is overestimated because of difficulty accessing pores by water under atmospheric pressure. As a result, porosity was underestimated.
Reference:
ÂNGULO, Sérgio Cirelli; SILVA, Raphael B. da; OLIVEIRA, Vinicius L. de; ULSEN, Carina. Caracterização das propriedades físicas dos agregados graúdos de RCD reciclados por picnometria de pó e gás. In: CONGRESSO BRASILEIRO DO CONCRETO, 54., 2012, Maceió. Anais… São Paulo: IBRACON, 2012. 12 p.
