The T-N (mg/l) concentration measurements from the
indoor water purification test according to aggregate sizeand the day when the measurements were taken are displayed
in Fig. 11. Regardless of aggregate size and P/G, the
T-N began to fall after the 3rd day of measurement. For the
porous concrete with 5 to 10 mm aggregate size, the T-N for
the porous concrete with P/G of 30% fell to 1.15 mg/l at the
7th day (with 44% reduction), the T-N for the porous
concrete with P/G of 40% dropped to 1.1 mg/l at the 11th
day (with 47% reduction), and the T-N for the porous
concrete with P/G 50% went down to 1.3 mg/l at the 7th