Sammendrag
Properties of bulk aggregate and concrete were investigated with RCA from the recycling plant of BA Gjenvinning in Oslo. The coarse RCA can probably be classified as Type II concrete aggregate following Rilem (and CEN) recommendations since absorption (5,7-6,3 %) and dry density (2280-2240 kg/m3) agree with typical RCA values. The sand with 12,8 - 14,7 % absorption and 1970 - 1910 kg/m3 density had low content of fines, giving good concrete workability at w/c = 0,60 and 365 kg/m3 cement. RCA concrete with density below 2000 kg/m3 had 50 - 55 % of the 28 day strength of granitic aggregate concrete. Frost testing of bulk coarse RCA could give rather high mass loss: 5,8 - 14,6 % in water and 27,2 - 40,4 % in 1 % NaCl. However, drying at 105 °C for 24 hours before freeze/thaw is not recommended since mass loss increased compared to 3 months drying in lab air before freeze/thaw. Furthermore, frost dilation testing of concrete made with wet and dry RCA demonstrated that the degree of saturation is the main factor governing frost damage in concrete with RCA.
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