Fig. 1
Results of tests on the strength of samples made of a mixture of normal temperature
| Content of additive (%) | W/C (%) | Strength indicators (MPa) | ||||||
|---|---|---|---|---|---|---|---|---|
| Ash | Acetone-formaldehyde additive | In 3 days hardening at 25°C | In 7 days hardening at 25°C | In 28 days hardening at 25°C | ||||
| Bend | Compression | Bend | Compression | Bend | Compression | |||
| Reference composition | 0.56 | 2.3 | 9.8 | 3.8 | 16 | 5 | 22 | |
| Without additives | 0.15 | 0.51 | 2.7 | 12 | 4.1 | 22 | 5.5 | 27.5 |
| 20 | - | 0.54 | 1.3 | 8 | 3.2 | 14 | 6 | 20.5 |
| 20 | 0.15 | 0.50 | 2.6 | 10 | 3.4 | 16.8 | 5.3 | 24 |
| 30 | - | 0.56 | 1.2 | 6.5 | 3 | 12.8 | 4.8 | 19.5 |
| 30 | 0.15 | 0.51 | 2.4 | 9.5 | 3.2 | 15.6 | 5.2 | 22.5 |
| 40 | - | 0.56 | 0.8 | 5.4 | 2.6 | 9.6 | 5.8 | 18 |
| 40 | 0.15 | 0.51 | 1.9 | 7 | 2.7 | 12.8 | 5 | 19.5 |
Results of tests on the strength of samples made of a mixture of an elevated temperature
| Content of additive (%) | W/C (%) | Strength indicators, MPa, in a day hardening at 50°C | ||||||
|---|---|---|---|---|---|---|---|---|
| Ash | SAFA | In 3 days hardening at 25°C | In 7 days hardening at 25°C | In 28 days hardening at 25°C | ||||
| Bend | Compression | Bend | Compression | Bend | Compression | |||
| Reference composition | 0.58 | 2.1 | 11 | 4 | 17 | 5.2 | 23.5 | |
| Without additives | 0.15 | 0.53 | 3.4 | 13.2 | 4.8 | 18.8 | 6 | 30.5 |
| 20 | - | 0.56 | 1.9 | 9 | 3.5 | 15.8 | 5 | 21.5 |
| 20 | 0.15 | 0.52 | 3.4 | 12.8 | 4.2 | 19 | 5.6 | 26.5 |
| 30 | - | 0.57 | 1.7 | 8 | 3.2 | 14 | 4.9 | 20 |
| 30 | 0.15 | 0.53 | 3 | 10 | 3.6 | 16.8 | 5.4 | 24 |
| 40 | - | 0.57 | 1.5 | 5 | 2.8 | 13.5 | 4.9 | 18.5 |
| 40 | 0.15 | 0.53 | 2.4 | 8 | 3 | 14.5 | 5.2 | 20.5 |
The results of the determination of water resistance
| Content of additive (%) | Pressure at which water filtration began, MPa in concrete brands | Water resistance grades, concrete brands | |||||
|---|---|---|---|---|---|---|---|
| Ash | Acetone-formaldehyde additive | 200 | 300 | 400 | 200 | 300 | 400 |
| 0 | 0 | 0.35 | 0.35 | 0.4 | B-4 | B-4 | B-4 |
| 0.15 | 0.76 | 0.75 | 0.8 | B-8 | B-8 | B-8 | |
| 20 | 0 | 0.26 | 0.2 | 0.25 | B-2 | B-2 | B-2 |
| 0.15 | 0.55 | 0.6 | 0.65 | B-6 | B-6 | B-6 | |
| 30 | 0 | 0.15 | 0.2 | 0.2 | B-2 | B-2 | B-2 |
| 0.15 | 0.55 | 0.6 | 0.6 | B-6 | B-6 | B-6 | |
| 40 | 0 | 0.15 | 0.15 | 0.2 | B-2 | B-2 | B-2 |
| 0.15 | 0.45 | 0.5 | 0.55 | B-6 | B-6 | B-6 | |
Strength gained with time
| Content of the components of the cement paste (%) | Strength of a sample of cement stone, MPa in a day | |||||
|---|---|---|---|---|---|---|
| Cement | Ash | Acetone-formaldehyde resins | 1 | 3 | 7 | 28 |
| 100 | - | - | 31 | 52 | 72 | 78 |
| 100 | - | 0.15 | 35 | 65 | 83 | 88 |
| 90 | 10 | - | 25 | 44 | 70 | 75 |
| 90 | 10 | 0.15 | 33 | 53 | 78 | 80 |
| 80 | 20 | - | 22 | 43 | 60 | 64 |
| 80 | 20 | 0.15 | 31 | 52 | 72 | 79 |
| 70 | 30 | - | 20 | 37 | 49 | 60 |
| 70 | 30 | 0.15 | 29 | 47 | 67 | 76 |
| 60 | 40 | - | 18 | 29 | 39 | 50 |
| 60 | 40 | 0.15 | 25 | 42 | 54 | 62 |
Compositions of heavy concretes
| Concrete grade | ||||
|---|---|---|---|---|
| Brand | Cement (g/cm3) | Sand (g/cm3) | Crushed stone (g/cm3) | Water (g/cm3) |
| 200 | 280 | 630 | 1,300 | 150 |
| 300 | 370 | 610 | 1,250 | 175 |
| 400 | 430 | 580 | 1,160 | 200 |
Normal density and setting time of cement paste
| Content of the components of the cement paste (%) | Normal density of the cement paste (g/cm3) | Setting time (h:min) | |||
|---|---|---|---|---|---|
| Cement | Ash | Acetone-formaldehyde resins | Start | Finish | |
| 100 | - | - | 27.5 | 1:30 | 7:15 |
| 100 | - | 0.15 | 23.5 | 2:15 | 6:00 |
| 90 | 10 | - | 28.0 | 2:00 | 8:25 |
| 90 | 10 | 0.15 | 26.0 | 2:40 | 6:45 |
| 80 | 20 | - | 29.0 | 2:40 | 8:45 |
| 80 | 20 | 0.15 | 27.0 | 2:55 | 7:00 |
| 70 | 30 | - | 30.0 | 2:55 | 8:55 |
| 70 | 30 | 0.15 | 27.5 | 3:15 | 7:20 |
| 60 | 40 | - | 30.5 | 3:20 | 9:15 |
| 60 | 40 | 0.15 | 28.0 | 3:35 | 7:35 |
The experimental results
| Concrete brand | Strength indicators of concrete, ordinary concrete (numerator) and ash concrete (denominator) | |
|---|---|---|
| After steaming | Over 28 days of curing | |
| 200 | 14.8/12.6 | 19.6/19.2 |
| 300 | 22.4/19.4 | 29.8/29 |
| 400 | 28.1/26.5 | 39.5/39.1 |
Workability of mortar mixes of the same mobility
| Content of additive (%) | W/C (%) | Mobility, cm (numerator)/cone spread, mm (denominator) | ||||||
|---|---|---|---|---|---|---|---|---|
| Ash | Acetone-formaldehyde additive | 0 min | 30 min | 60 min | 90 min | 120 min | 135 min | |
| At normal temperature | ||||||||
| Reference mixture | 0.56 | 4.3/141 | 3.8/134 | 3.4/125 | 3.0/118 | - | - | |
| Without additives | 0.15 | 0.51 | 4.5/143 | 4.0/139 | 3.6/132 | 3.3/127 | 3.0/122 | - |
| 20 | - | 0.54 | 4.2/142 | 3.8/138 | 3.5/130 | 3.2/125 | 2.9/120 | - |
| 30 | - | 0.55 | 4.0/140 | 3.7/135 | 3.5/128 | 3.2/123 | 3.0/119 | - |
| 40 | - | 0.55 | 3.8/138 | 3.6/132 | 3.4/126 | 3.1/121 | 2.8/118 | - |
| 20 | 0.15 | 0.50 | 4.2/141 | 3.8/137 | 3.5/132 | 3.3/128 | 3.0/122 | - |
| 30 | 0.15 | 0.51 | 4.0/140 | 3.7/136 | 3.4/130 | 3.1/126 | 2.9/121 | - |
| 40 | 0.15 | 0.51 | 3.8/139 | 3.6/135 | 3.3/129 | 3.0/124 | 2.8/119 | - |
| At 50°C | ||||||||
| 0 min | 15 min | 30 min | 45 min | 60 min | 75 min | |||
| Reference mixture | 0.58 | 4.0/140 | 3.5/128 | 3.0/121 | - | - | - | |
| Without additives | 0.15 | 0.53 | 4.1/140 | 3.7/133 | 3.2/126 | 2.9/120 | - | - |
| 20 | - | 0.56 | 4.1/141 | 3.8/135 | 3.5/130 | 3.2/125 | - | - |
| 30 | - | 0.57 | 3.9/139 | 3.6/135 | 3.4/129 | 3.1/124 | - | - |
| 40 | - | 0.57 | 3.8/138 | 3.5/133 | 3.1/126 | 2.8/120 | - | - |
| 20 | 0.15 | 0.52 | 4.2/142 | 3.9/137 | 3.6/134 | 3.3/129 | 3.0/123 | - |
| 30 | 0.15 | 0.53 | 4.0/140 | 3.6/136 | 3.3/133 | 3.0/128 | 2.8/122 | - |
| 40 | 0.15 | 0.53 | 3.8/139 | 3.5/135 | 3.2/131 | 2.9/124 | - | - |
Indicators of the workability of the mortar mix
| Content of additive (%) | W/C (%) | Mobility, cm (numerator)/cone spread, mm (denominator) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Ash | SAFA | 0 min | 30 min | 60 min | 90 min | 120 min | 150 min | 180 min | 210 min | |
| At normal temperature | ||||||||||
| Reference mixture | 0.56 | 4.3/142 | 3.8/129 | 3.4/125 | 3.0/118 | - | - | - | - | |
| Without additives | 0.15 | 0.56 | 5.5/160 | 5.2/155 | 4.7/148 | 4.3/140 | 3.9/132 | 3.5/125 | 3.0/119 | - |
| 20 | - | 0.56 | 5.2/155 | 5.1/152 | 5.0/150 | 4.8/147 | 4.2/140 | 3.8/132 | 3.5/125 | 3.0/120 |
| 30 | - | 0.56 | 4.8/149 | 4.6/147 | 4.5/145 | 4.2/142 | 3.8/136 | 3.4/129 | 3.0/122 | - |
| 40 | - | 0.56 | 4.6/147 | 4.5/145 | 4.4/143 | 4.0/140 | 3.6/133 | 3.3/127 | 3.0/120 | - |
| 20 | 0.15 | 0.56 | 6.8/170 | 6.7/168 | 6.6/165 | 6.3/163 | 6.0/160 | 5.5/154 | 5.0/149 | 4.2/140 |
| 30 | 0.15 | 0.56 | 6.3/167 | 6.1/165 | 5.9/163 | 5.6/160 | 5.3/156 | 5.0/150 | 4.4/143 | 3.8/135 |
| 40 | 0.15 | 0.56 | 5.6/165 | 5.5/163 | 5.3/161 | 5.0/158 | 4.7/155 | 4.2/147 | 3.8/142 | 3.2/134 |
| Ash | SAFA | W/C (%) | 0 min | 15 min | 30 min | 45 min | 60 min | 75 min | 90 min | |
| At 50°C | ||||||||||
| Without additives | 0.15 | 0.58 | 4.0/140 | 3.5/128 | 3.0/121 | - | - | - | - | |
| 20 | - | 0.58 | 5.0/155 | 4.5/150 | 4.0/145 | 3.5/130 | 3.0/125 | - | - | |
| 30 | - | 0.58 | 4.5/142 | 4.2/138 | 3.8/135 | 3.3/130 | - | - | - | |
| 40 | - | 0.58 | 4.2/140 | 3.8/135 | 3.3/132 | 3.0/128 | - | - | - | |
| 20 | 0.15 | 0.58 | 6.0/158 | 5.5/152 | 4.7/147 | 4.2/141 | 3.6/134 | 3.5/134 | 3.2/129 | |
| 30 | 0.15 | 0.58 | 5.6/156 | 5.1/150 | 4.7/145 | 4.2/137 | 3.6/134 | 3.2/128 | 2.9/122 | |
| 40 | 0.15 | 0.58 | 5.4/154 | 5.0/148 | 4.5/142 | 4.0/135 | 3.4/131 | 3.0/124 | - | |
Strength of ash concrete
| Ash content in concrete mix (%) | Content of acetone-formaldehyde additive (%) | Compressive strength of concrete brands (MPa) | ||
|---|---|---|---|---|
| 200 | 300 | 400 | ||
| 0 | 0 | 20.3 | 30.2 | 40.5 |
| 0.1 | 22.5 | 34.9 | 47.5 | |
| 0.15 | 24.8 | 36.5 | 50.2 | |
| 0.2 | 21 | 30 | 39.6 | |
| 20 | 0 | 15.9 | 24.5 | 32.5 |
| 0.1 | 17.8 | 28.7 | 38.1 | |
| 0.15 | 19.2 | 31 | 40 | |
| 0.2 | 14.7 | 22.7 | 31.7 | |
| 30 | 0 | 14.5 | 22 | 30 |
| 0.1 | 16.5 | 25.6 | 35.7 | |
| 0.15 | 17.9 | 27.5 | 38 | |
| 0.2 | 13.1 | 20.7 | 29.5 | |
| 40 | 0 | 12.5 | 18.3 | 24.5 |
| 0.1 | 13.7 | 19.8 | 28.7 | |
| 0.15 | 14.5 | 21 | 30.2 | |
| 0.2 | 11.7 | 17.8 | 23.5 | |
Chemical composition of ashes
| Basic oxides | Coal ash (%) | Shale ash (%) | Peat ash (%) | |||
|---|---|---|---|---|---|---|
| Anthracite | Stone | Brown | Siliceous | Calcified | ||
| Si2O3 | 16–50 | 22–60 | 31–58 | 20–60 | 42 | 15 |
| Al2O3 | 5–37 | 15–43 | 20–45 | 5–20 | 16 | 10 |
| Fe2O3 | 5–40 | 3–32 | 2–45 | 2–10 | 17 | 15 |
| CaO | Up to 3 | Up to 5 | Up to 50 | 10–15 | 18 | 50 |
Cement activity
| Hardening age (days) | 3 | 7 | 28 | |||
|---|---|---|---|---|---|---|
| Brand | Compression (MPa) | Bending (MPa) | Compression (MPa) | Bending (MPa) | Compression (MPa) | Bending (MPa) |
| 500 | 20.5 | 1.2 | 27.2 | 6.0 | 50.2 | 6.1 |
| 400 | 15.9 | 3.0 | 24.2 | 4.8 | 39.8 | 5.2 |
Determination of the strength of samples made of a mixture of normal temperature
| Content of additive (%) | W/C (%) | Strength indicators (MPa) | ||||||
|---|---|---|---|---|---|---|---|---|
| Ash | SAFA | In 3 days hardening at 25°C | In 7 days hardening at 25°C | In 28 days hardening at 25°C | ||||
| Bend | Compression | Bend | Compression | Bend | Compression | |||
| Reference composition | 0.58 | 1.8 | 8.8 | 2.4 | 13 | 3.9 | 19.2 | |
| Without additives | 0.15 | 0.52 | 2 | 10.2 | 2.8 | 15.9 | 4.4 | 24.2 |
| 20 | - | 0.57 | 1.3 | 7 | 1.8 | 11.8 | 3.3 | 18 |
| 20 | 0.15 | 0.51 | 1.5 | 8 | 2.2 | 13.5 | 3.8 | 22 |
| 30 | - | 0.58 | 1.0 | 5.7 | 1.6 | 10 | 3 | 17 |
| 30 | 0.15 | 0.53 | 1.3 | 7.2 | 2 | 11.5 | 3.2 | 20.5 |
| 40 | - | 0.58 | 0.8 | 5.2 | 1.3 | 6.8 | 2.8 | 15 |
| 40 | 0.15 | 0.53 | 1 | 5.3 | 1.7 | 8.7 | 3 | 18 |