Porous slag blocks (1 m(3)) were produced by carbonation of steelmaking sla
g over a period of 12 days. The compressive strength and bulk density of th
e blocks were 18.4 +/ 3.3 MPa and 2.4 g/cm(3), respectively. To make a larg
e block, the optimum amount of water and bulk density of the compact were 5
.3-6.3 mass% and 2.30-2.37 g/cm(3), respectively. The carbonation reaction
occurred homogeneously in the blocks, and the amount of CO2 that reacted wi
th the slag was approximately 6 mass% at all depths from the surface of the
block. When left exposed to various weather conditions for 1 year, the blo
cks showed no cracks or destruction.