Table 3.
Chemical composition according to X-ray fluorescence spectroscopy analyses (XRF), alkali-activating solution details, curing conditions, and compressive strength of alkali-activated materials containing carbonate minerals.
| Mineral Additive (Chemical Composition) | Alkali-Activation and Curing Regimen | Max. Compressive Strength + | Reference |
|---|---|---|---|
| Calcite (53.5% CaO; 1.7% MgO; 1.5% SiO2) | Ms * = 2.0, 1.5, and 1.2 | ~60 MPa (Ms = 1.5, MK with 20% of calcite) | [55] |
| 40 °C for 24 h | |||
| Calcite (55.91% CaO; 0.18% K2O; 0.09% SiO2) | 2%, 4%, and 6% of NaOH | ~70 MPa (4% of NaOH, 5% of calcite, and 91% of GBFS) | [56] |
| 37 °C 100% RH | |||
| Calcite (purity 98.5%) | 13% KOH, 10% NaOH, 27% Na2SiO3, 50% H2O | ~28 MPa (MK with 6% of calcite) | [57] |
| 40 °C for 12 h | |||
| Calcite (50.1% CaO; 3.9% SiO2; 1.7% Al2O3) | 3, 6, and 12 M NaOH | 19.2 MPa (12 M, 67% mineral addition, 5 h curing) | [58] |
| 80 °C for 1, 3, and 5 h | |||
| Marble (53.68% CaO; 1.32% Fe2O3; 0.26% SiO2) | 1, 5, and 10 M NaOH | 37.48 MPa (10 M NaOH, curing 20 °C, 20% Marble) | [63] |
| (1) 22 °C and 40% RH; (2) 45 °C for 24 h; (3) 75 °C for 24 h. Afterwards, wet condition (min. 95% RH) or 22 °C and 35% RH | |||
| Marble (55.9% CaO; 0.6% MgO; 0.1% Fe2O3) | (1) 0.1 mol of Na2O; (2) 0.1 mol of Na2O and 0.1 mol SiO2; (3) substitution of sodium citrate (Na3C6H5O7) | 60.7 MPa (25% Marble/75% calcined smectite clay; containing Na-citrate) | [64] |
| 24 h at 95% RH then dry-cured at room temperature | |||
| Marble (44.20% CaO; 1.41% MgO; 0.07% Fe2O3) | Ms * = 1.65 and 3.50 | 38.30 MPa (Ms = 1.65, dry curing) | [45] |
| 24 h at 80 °C then: (1) 20 °C and 95% RH; (2) 20 °C and 18% RH; (3) immersed in water | |||
| Marble (45.60% CaO; 6.82% MgO; 0.70% SiO2) | 8 M NaOH or Na2SiO3·nH2O:NaOH (w:w = 5) | 52 MPa (Na2SiO3·nH2O + NaOH; cement, GBFS, marble, FA) | [65] |
| Room temperature | |||
| Marble (38.02% CaO; 34.66% SiO2; 13.12% Fe2O3; 7.21% MgO) | 2 and 4 M NaOH + Na2SiO3 | 6.52 MPa (7 days, 4 M, 60% marble + 40% FA) | [66] |
| 70 °C for 24 h and 7 days in plastic bags | |||
| Travertine (55.10% CaO; 0.70% SiO2; 0.20% Fe2O3) | 1, 5, and 10 M NaOH | 42.24 MPa (10 M NaOH, dry curing at 20 °C, 20% travertine) | [63] |
| (1) 22 °C and 40% RH; (2) 45 °C for 24 h; (3) 75 °C for 24 h. Afterwards, wet condition (min. 95% RH) or 22 °C and 35% RH | |||
| Dolomite (33.4% CaO; 17.1% MgO; 2.5% SiO2) | Ms * = 2.0, 1.5, and 1.2 | ~45 MPa (Ms = 1.5, MK with 20% of dolomite) | [55] |
| 40 °C for 24 h | |||
| Dolomite (42.48% CaO, 19.15% MgO) | Ms * = 2.5 (Na2CO3 and bentonite) | 38.3 MPa (bentonite, dolomite and Na2CO3 calcined at 1110 °C and (CaO + MgO)/SiO2 = 2.1) | [60] |
| 80 °C for 3 days | |||
| Dolomite (74.8% CaO; 18.3% MgO; 3.7% SiO2) | Ms *= 0.93 (10 M NaOH + Na2SiO3) | ~60 MPa (Cement with 40% of dolomite); ~40 MPa (FA with 40% of dolomite); | [62] |
| Cement-based samples 24 h at 100% RH then immersed in lime water; FA-based samples 24 h at 40 °C and 100 % RH then sealed and at room temperature | |||
| Dolomite (31.4% CaO, 21.3% MgO, 1.1% SiO2) | Na2CO3 + calcined dolomite (Na2O = 4.9%–7.6% in the dry mixture) |
41.6 MPa (GBFS with 10% of calcined dolomite and 10% of Na2CO3) | [61] |
| 20 °C and RH > 95% ± 2% | |||
| Dolomite (27.13% CaO; 24.53% MgO; 0.13% SiO2) | 4 M NaOH or 2 M Na2CO3 | ~60 MPa (NaOH, GBFS and 20% of dolomite); ~80 MPa (Na2CO3, GBFS and 20% of dolomite); |
[59] |
| 20 °C 100% RH | |||
| Pietra di Angera (64% CaO; 33% MgO; 2.2% Fe2O3) | 10, 14, 16, and 20 H2O/Na2O molar ratio (obtained mixing H2O + Na2SiO3 + NaOH) | 18 MPa (H2O/Na2O molar ratio = 20; MK:pietra di Angera = 1:1) | [50] |
| 20 °C and 90% RH | |||
| Limestone (53.5% CaO; 1.7% MgO; 1.5% SiO2) | 3 and 5 M NaOH | 7 MPa (50% LM/50% MK; 5 M NaOH; 20 °C; dry curing) | [67] |
| 24 h at 20 or 80 °C then wet curing (water immersed) or dry curing (laboratory conditions) | |||
| Limestone (53.96% CaO; 1.01% MgO; 0.84% SiO2) | Ms * = 1.4 | 83.5 MPa (30% LM/10% FA/60% GBFS) | [68] |
| 20 °C and 95% RH | |||
| Limestone (53.96% CaO; 1.01% MgO; 0.84% SiO2) | 4 wt.% of Na2O (starting from Na2CO3) | ~55 MPa (GBFS with 10% of LM) | [69,70] |
| 20 °C and 95% RH | |||
| Limestone (57.43% CaO; 1.06% SiO2) | Ms * = 0 (only NaOH), 1, and 1.5 | ~15 MPa (Ms = 1, 10% Na2O) | [40] |
| 24 h at 60 °C then dry stored in plastic bags at 20 °C and 80%–90% RH | |||
| Limestone (47.85% CaO; 9.07% SiO2; 1.51% Al2O3) | 5, 10, and 8 M NaOH + Na2SiO3 | 47.77 MPa (8 M, 45% LM/55% Clay) | [71] |
| 24 °C in open air | |||
| Limestone 1 (90% calcite, 9% quartz) (43.31% CaO; 14.26% SiO2; 2.44% Al2O3) | NaOH + Na2CO3 + H2O | 39 MPa (30% LM_3/70% GBFS; Ssp 600 m2/kg) | [72] |
| Limestone 2 (33% calcite, 66% dolomite) (39.79% CaO; 1.26% SiO2; 12.94% MgO) | |||
| Limestone 3 (100% calcite) (55.06% CaO; 0.47% SiO2; 0.49% MgO) | Room temperature and 95%–100% RH |
+ 28 days. * Ms = SiO2/Na2O molar ratio.