6.2. Compressive strength
As the porous concrete matured, its compressive strength
increased as displayed in Fig. 4. At ages from 28 to 90 days,
a relatively smaller increase in the compressive strength was
noticed. The compressive strengths of the concretes with the
same P/G according to the aggregate size are shown in Figs.
4 and 5. The concretes with 5 to 10 mm aggregate size
exhibited 1.8 to 2.0 times greater strength than those with 10
to 20 mm aggregate size. This is considered to be related to
the actual loading area. There was a larger load contact
surface between the aggregate and the cement paste of the