Fig. 1
![Results of the 2019 Global Carbon Budget Survey (by country) [3].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64725239215d2f6c89dc418d/j_msp-2021-0004_fig_001.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251204%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251204T131713Z&X-Amz-Expires=3600&X-Amz-Signature=b083d304d9b369aa9e4ef22f1ddb9a62145711e577b5e81d2b4dea1de70bc7de&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Fig. 2
![2019 Global Carbon Budget Survey Results (by Industry) [3].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64725239215d2f6c89dc418d/j_msp-2021-0004_fig_002.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251204%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251204T131713Z&X-Amz-Expires=3600&X-Amz-Signature=6137a61a3baaef2c95e49dd7a96ab4ac5e4cccaf16ec2238e5520dbbc547dc8b&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
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ACI 229 recommended dosage for the CLSM_
| Material | Recommended dosage (kg/m3) |
|---|---|
| Cement | 30–120 |
| Class F fly ash (when used instead of fine particles) | 0–1200 |
| Class C fly ash | 0–210 |
| Fine aggregate | 1500–1800 |
| Water | 193–344 |
| Water (when using Class F fly ash) | 590 |
Proportioning design of the CLSM pastes_
| Numbering | CFA (%) | GGBS (%) |
|---|---|---|
| F100 | 100 | 0 |
| F75 | 75 | 25 |
| F50 | 50 | 50 |
| F25 | 25 | 75 |
| F0 | 0 | 100 |
Fresh properties for the mixing materials of the CLSM_
| Material | Advantage | Disadvantage |
|---|---|---|
| CFA | Improve the consistency of the V type | Minimum slump |
| Reduce the possibility of a box-type passage | ||
| Reduce stress resistance | ||
| GGBS | Improve fluidity and slump | Increase compression value |
| Improve stress resistance | ||
| Methylcellulose | Improve consistency | Reduce the possibility of a box-type passage |
| Extend V-type test time | Retard | |
| Superplasticizers | Increase fluidity | Expensive |
| Accelerators | Offset time | Reduce slump |
Compressive strength of the paste specimens at seven days (MPa)_
| Paste specimens Value | F100 | F75 | F50 | F25 | F0 |
|---|---|---|---|---|---|
| 1 | – | 4.71 | 8.14 | 10.00 | – |
| 2 | – | 4.51 | 6.76 | 9.80 | – |
| 3 | – | 4.61 | 7.84 | 9.71 | – |
| Average | – | 4.61 | 7.58 | 9.84 | – |
Fluidities for the strength activity index testing_
| Type | Flowability (cm) | Water (g) |
|---|---|---|
| GGBS | 16.0–21.0 | 230–260 |
| CFA | 11.5–22.4 | 230–270 |
SCC grading table_
| Grade Type | 1 | 2 | 3 |
|---|---|---|---|
| Box test (mm) | Over 300 (R1 disorder) | Over 300 (R2 disorder) | Over 300 (Accessibility) |
| Flowability (mm) | 650~750 | 600~700 | 500~650 |
| V type test (sec) | 10~25 | 7~20 | 7~20 |
Mix design for the activity index test (kg/m3)_
| Specimen No. | Cement | Standard sand | CFA | GGBS | Water |
|---|---|---|---|---|---|
| A-C | 500 | 1375 | 242 | ||
| A-F | 400 | 1375 | 100 | 252 | |
| A-S | 400 | 1375 | 100 | 240 |
Weather observation data_
| Age | Temperature (°C) | Max. temperature (°C) | Min. temperature (°C) | Relative humidity (%) | Precipitation (mm) | Precipitation hours (hr) | Maximum hourly precipitation (mm) | Sunshine hours (hr) | Sunshine rate (%) |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 28.4 | 32.8 | 24.4 | 84 | T | 0.3 | T | 8.9 | 65.4 |
| 2 | 28.5 | 33.6 | 25.5 | 83 | 0.7 | 3.1 | 0.5 | 8.7 | 63.9 |
| 3 | 27.8 | 32.5 | 25.0 | 85 | 13.6 | 4.7 | 6.2 | 1.6 | 11.7 |
| 4 | 28.3 | 32.5 | 25.0 | 88 | 0.0 | 0.0 | 0.0 | 6.7 | 49.2 |
| 5 | 25.9 | 28.6 | 23.8 | 93 | 28.6 | 12.8 | 5.5 | 0.0 | 0.0 |
| 6 | 23.4 | 24.7 | 22.6 | 94 | 31.0 | 22.5 | 6.5 | 0.0 | 0.0 |
| 7 | 24.9 | 28.7 | 22.9 | 92 | 6.5 | 8.1 | 2.5 | 0.7 | 5.1 |
| 8 | 24.6 | 27.4 | 23.5 | 94 | 20.9 | 16.0 | 5.6 | 0.0 | 0.0 |
| 9 | 24.9 | 27.5 | 23.2 | 94 | 11.0 | 21.2 | 4.0 | 0.0 | 0.0 |
| 10 | 26.2 | 29.8 | 24.1 | 89 | T | 1.9 | T | 0.1 | 0.7 |
| 11 | 27.3 | 31.2 | 24.2 | 80 | 0.0 | 0.0 | 0.0 | 0.8 | 5.9 |
| 12 | 28.1 | 32.2 | 25.5 | 81 | 0.5 | 2.0 | 0.5 | 0.3 | 2.2 |
| 13 | 28.7 | 33.3 | 24.1 | 79 | 0.0 | 0.0 | 0.0 | 7.4 | 54.3 |
| 14 | 28.7 | 33.6 | 25.5 | 84 | 0.8 | 1.7 | 0.8 | 8.1 | 59.4 |
| 15 | 28.9 | 33.8 | 25.6 | 85 | 0.0 | 0.0 | 0.0 | 8.5 | 62.4 |
| 16 | 29.6 | 34.1 | 26.2 | 82 | 0.0 | 0.0 | 0.0 | 8.6 | 63.1 |
| 17 | 29.7 | 33.2 | 26.3 | 81 | 0.0 | 0.0 | 0.0 | 6.7 | 49.2 |
| 18 | 28.7 | 33.4 | 25.8 | 89 | 26.5 | 3.5 | 26.0 | 4.7 | 34.5 |
| 19 | 29.0 | 33.0 | 25.1 | 87 | T | 1.0 | T | 9.5 | 69.8 |
| 20 | 29.6 | 33.0 | 26.1 | 82 | 0.0 | 0.0 | 0.0 | 10.2 | 74.9 |
| 21 | 29.6 | 33.2 | 27.1 | 83 | 0.0 | 0.0 | 0.0 | 6.9 | 50.7 |
| 22 | 29.3 | 34.5 | 26.1 | 82 | 9.1 | 2.1 | 7.5 | 8.3 | 61.0 |
| 23 | 29.1 | 33.0 | 25.1 | 84 | 0.1 | 0.2 | 0.1 | 11.4 | 83.8 |
| 24 | 29.1 | 33.7 | 26.2 | 83 | 0.4 | 0.8 | 0.3 | 5.6 | 41.2 |
| 25 | 28.9 | 32.6 | 25.9 | 82 | 0.0 | 0.0 | 0.0 | 5.7 | 41.9 |
| 26 | 29.7 | 34.4 | 26.0 | 76 | 0.0 | 0.0 | 0.0 | 8.0 | 58.9 |
| 27 | 29.7 | 33.5 | 26.5 | 80 | 0.0 | 0.0 | 0.0 | 10.3 | 75.8 |
| 28 | 28.4 | 33.3 | 24.7 | 83 | 34.4 | 3.0 | 31.5 | 0.5 | 3.7 |
Chemical compositions of CFA_
| Composition | Value (%) | Composition | Value (%) | ||
|---|---|---|---|---|---|
| Sample I | Sample II | Sample I | Sample II | ||
| Na2O | 0.75 | 0.00 | Fe2O3 | 3.49 | 3.34 |
| MgO | 1.82 | 2.15 | NiO | 0.00 | 0.00 |
| Al2O3 | 19.27 | 12.21 | Co2O3 | 0.00 | 0.05 |
| SiO2 | 29.47 | 26.21 | CuO | 0.00 | 0.04 |
| P2O5 | 0.47 | 0.67 | ZnO | 0.08 | 3.11 |
| SO3 | 7.36 | 10.35 | As2O3 | 0.00 | 0.00 |
| Cl | 0.07 | 0.14 | Br | 0.01 | 0.04 |
| K2O | 1.02 | 0.90 | Rb2O | 0.00 | 0.00 |
| CaO | 35.54 | 40.24 | SrO | 0.05 | 0.04 |
| TiO2 | 0.55 | 0.49 | ZnO2 | 0.00 | 0.00 |
| Cr2O3 | 0.00 | 0.00 | Y2O3 | 0.00 | 0.00 |
| MnO | 0.05 | 0.05 | ZrO2 | 0.02 | 0.03 |
Mix design of CLSM (kg/m3)_
| Mix No. | w/c | Cement | CFA GGBS | Coarse Aggregates | Fine Aggregates | Water | Superplasticizer | Accelerator | Adhesive |
|---|---|---|---|---|---|---|---|---|---|
| T1 | 31.5 | 94.7 155.5 | 1304.0 | 242.5 | 3.2 | 0.060 | |||
| T2 | 47.3 | 142.0 233.3 | 806.8 | 376.4 | 3.2 | 0.060 | |||
| T3 | 34.7 | 104.2 171.1 | 1204.5 | 269.3 | 3.2 | 0.090 | |||
| T4 | 69.3 | 136.9 101.4 | 1204.3 | 269.3 | 3.2 | 0.320 | |||
| T5 | 0.85 | 69.3 | 162.0 76.0 | 400.5 | 1204.2 | 268.9 | 22.1 | 3.2 | 0.410 |
| T6 | 104.0 | 121.5 88.7 | 1204.2 | 267.4 | 5.0 | 0.473 | |||
| T7 | 69.3 | 162.0 76.0 | 1204.2 | 262.0 | 10.0 | 0.473 | |||
| T8 | 69.3 | 162.0 76.0 | 1204.2 | 262.0 | 10.0 | 0.410 | |||
| T9 | 69.3 | 162.0 76.0 | 1204.2 | 268.0 | 4.0 | 0.410 | |||
| T10 | 69.3 | 162.0 76.0 | 1204.2 | 268.4 | 3.6 | 0.410 |
Fresh properties of the CLSM_
| Mix no. | V type test (sec) | Box test | Flowability (cm) | Tube fluidity (cm) |
|---|---|---|---|---|
| T1 | 6 | Pass | 59.5 | 20.0 |
| T2 | Severe bleeding | |||
| T3 | 4 | Severe bleeding | ||
| T4 | 6 | Did not pass | 57.5 | 23.0 |
| T5 | 7 | Pass | 64.0 | 21.5 |
| T6 | 6 | Did not pass | 49.5 | 19.5 |
| T7 | 17 | Did not pass | 38.0 | 15.0 |
| T8 | Rapid hardening | |||
| T9 | 11 | Pass | 46.5 | 18.5 |
| T10 | 7 | Pass | 50.0 | 20.0 |
Designed compressive strength for various backfill materials [35, 36, 37]_
| Items | Backfill material | Compressive strength |
|---|---|---|
| 1 | Specification requirements | 8.3 MPa (1200 psi) |
| 2 | Recommended strength | 2.1 MPa (300 psi) |
| 3 | CLSM long-term compressive strength | 0.3 MPa–2.1 MPa (50 psi–300 psi) |
| 4 | Equivalent to good compaction | 0.35 MPa–0.7 MPa (50 psi–100 psi) |
| 5 | Foundation support | 0.7 MPa–8.3 MPa (100 psi–1200 psi) |
| 6 | Subgrade | 2.8 MPa–8.3 MPa (400 psi–1200 psi) |
| 7 | Can be manually mined | 0.3 MPa (50 psi) |
| 8 | Reliable mechanical digging | 0.7 MPa–1.4 MPa (100 psi–200 psi) |
| 9 | The strength that can be excavated only when using fine sand or fly ash as the granular material | 2.1 MPa (300 psi) |
Optimal mix design of the CLSM using a higher amount of cement replacement_
| Material | Value |
|---|---|
| Water–cement ratio | 0.85 |
| Cement | 69.3 kg/m3 |
| CFA | 162.0 kg/m3 |
| GGBS | 76.0 kg/m3 |
| Coarse aggregate | 400.5 kg/m3 |
| Fine aggregate | 1204.2 kg/m3 |
| water | 268.4 kg/m3 |
| Superplasticizers | 22.5 kg/m3 |
| Adhesives | 0.410 kg/m3 |
| Accelerators | 3.6 kg/m3 |
| Unit weight | 2527 kg/m3 |
Chemical compositions of CFA and GGBS_
| Composition | CFA | GGBS |
|---|---|---|
| Content, wt. (%) | ||
| Silicon dioxide (SiO2) | 29.47 | 33.68 |
| Aluminium oxide (Al2O3) | 19.27 | 14.37 |
| Ferric oxide (Fe2O3) | 3.49 | 0.29 |
| Calcium oxide (CaO) | 35.54 | 40.24 |
| Magnesium oxide (MgO) | 1.82 | 7.83 |
| Sulphur trioxide (SO3) | 7.36 | 0.66 |
| Others | 3.05 | 2.93 |
Compressive strength (MPa)_
| Method | 7-day | 14-day | 28-day |
|---|---|---|---|
| Atmospheric exposure (A) | 2.84 | 5.20 | 5.78 |
| Water curing (W) | 2.94 | 4.51 | 5.39 |
| Indoor dry curing (E) | 3.43 | 4.31 | 5.59 |
Pozzolanic strength activity index results_
| Mix no. | Compressive Strength (MPa) | |
|---|---|---|
| 7 days | 28 days | |
| A-C | 32.16 | 44.80 |
| A-F | 31.96 | 41.18 |
| A-S | 31.27 | 50.20 |
| Material | Strength Activity Index | |
| 7 days | 28 days | |
| CFA | 99% | 92% |
| GGBS | 97% | 112% |
Chloride diffusion coefficient from the accelerated chloride migration test (10−12 m2/s)_
| Method | 7-day | 14-day | 28-day |
|---|---|---|---|
| Atmospheric exposure (A) | 2.62 | 2.21 | 0.51 |
| Water curing (W) | 3.02 | 1.43 | 0.14 |
| Indoor dry curing (E) | 3.90 | 1.89 | 1.75 |