Table 4.

Experiment procedures and main parameters.

Sequence of Steps	Making and Curing	Drying	Covering	Carbonizing	Loading and Testing
Parameter setting	Standard curing for 28 d	Drying for 48 h at 60 °C	Covering 5 surfaces with paraffin and leaving a carbonized surface	CO2 levels: (20 ± 3)% Temperature: (20 ± 2) °C Humidity: (60 ± 5)%	Loading rate: 0.5 MPa/s (compressive strength) 0.05 MPa/s (tensile strength)