Figure 1:
Gonghe-Yushu Expressway
Figure 2:
Rock subgrades
Figure 3:
Particle-size distribution curves of the aggregates
Figure 4:
Test flow chart
Table 1:
Overview of tests
| Tests | Curing age [d] | CO2 curing [h] | Number of specimens [n] |
|---|---|---|---|
| Basic physical parameters | 3 7 28 | 0 2 4 6 | 3 |
| Uniaxial compression test | |||
| XRD test | |||
| NMR test |
Table 2:
Basic physical parameters
| Test specimen | UPV [m/s] | ρd [g/cm3] | ρsa [g/cm3] | ω [%] | Porosity n [%] |
|---|---|---|---|---|---|
| Recovery of weathered limestone | 4310 | 2.36 | 2.46 | 4.23 | 9.98 |
Figure 5:
Variation of mass of weathered limestone specimens
Figure 6:
Variation of UPV of weathered limestone specimens
Figure 7:
Stress-strain curves of recycled weathered limestone under uniaxial compression
Table 3:
Uniaxial peak strength
| Test specimen | Curing condition | Peak strength [MPa] |
|---|---|---|
| Recovery of weathered limestone | 3 d, CO2 0 h | 16.58 |
| 3 d, CO2 2 h | 19.72 | |
| 3 d, CO2 4 h | 21.09 | |
| 3 d, CO2 6 h | 22.02 | |
| 7 d, CO2 0 h | 20.02 | |
| 7 d, CO2 2 h | 23.38 | |
| 7 d, CO2 4 h | 23.94 | |
| 7 d, CO2 6 h | 24.15 | |
| 28 d, CO2 0 h | 36.30 | |
| 28 d, CO2 2 h | 37.21 | |
| 28 d, CO2 4 h | 37.42 | |
| 28 d, CO2 6 h | 38.38 |
Figure 8:
Typical failure modes of weathered limestone concrete under uniaxial compression
Figure 9:
X-ray diffraction patterns and mineral composition of weathered limestone concrete
Figure 10:
X-ray diffraction patterns and mineral composition of weathered limestone concrete
Figure 11:
T2 spectra of recycled weathered limestone under different curing conditions
Figure 12:
Colour change of sample
Figure 13:
Carbonation depth of recycled weathered limestone concrete
Figure 14:
Schematic illustration of carbonation-hydration reactions