1 Introduction
2 Research Program
3 Phase-I Investigation
3.1 Materials
Cement | Fly ash | Silica fume | Expanded shale | |
---|---|---|---|---|
Chemical | ||||
SiO2 (%) | 19.6 | 46.7 | 95.21 | 67.6 |
Al2O3 (%) | 4.9 | 22.8 | 0.21 | 15.1 |
Fe2O3 (%) | 3.1 | 15.5 | 0.13 | 4.1 |
TiO2 (%) | – | – | – | 0.6 |
CaO (%) | 61.4 | 5.8 | 0.23 | 2.2 |
MgO (%) | 3 | – | – | 3.5 |
SO3 (%) | 3.6 | 0.5 | 0.33 | 0.24 |
Alkalis as Na2O (%) | 0.7 | 0.7 | 0.85 | 3.7 |
LOI (%) | 2.3 | 2.2 | 1.97 | 3.06 |
Physical | ||||
Blaine (cm2/g) | 3,870 | 3,060 | 21,000 | – |
+45 µm (%) | 3.00 | 17 | 2.85 | – |
Density (g/cm3) | 3.15 | 2.48 | 2.20 | – |
Sieve size (mm) | % Passing | |||
---|---|---|---|---|
ASTM C-330 specification | E-shale | |||
Fine | Coarse | Fine | Coarse | |
13.20 | 100 | 100 | 100 | 100 |
9.50 | 80–100 | 100 | 100 | 91 |
4.75 | 5–40 | 85–100 | 100 | 18.8 |
2.36 | 0–20 | – | 95 | 2.5 |
1.18 | 0–10 | 40-80 | 65 | 1.6 |
0.60 | – | – | 41 | 0.6 |
0.30 | – | 10–35 | 23.5 | 0.1 |
0.15 | – | 5–25 | 14.7 | 0 |
Bulk specific gravity (dry) | – | – | 1.40 | 1.33 |
Bulk specific gravity (SSD) | – | – | 1.81 | 1.71 |
Dry loose bulk density (kg/m3) | 1,120 (max) | 880 (max) | 1,070 | 862 |
Absorption (%) | – | – | 13 | 14 |
3.2 Mix Design Methodology and Mixture Proportions (Phase I)
Factor | Range | Coded value | ||||
---|---|---|---|---|---|---|
−1.414 | −1 | 0 | +1 | +1.414 | ||
X1 = (w/b) | 0.30–0.40 | 0.28 | 0.30 | 0.35 | 0.40 | 0.42 |
X2 = (% of HRWRA) | 0.3–1.2 % | 0.11 | 0.30 | 0.75 | 1.2 | 1.39 |
X3 = (B) kg/m3
| 410–550 | 380 | 410 | 480 | 550 | 580 |
Factors | ||||
---|---|---|---|---|
CCD portion | Mixture | X1 | X2 | X3 |
Fractional factorial | 1–8 | ±1 | ±1 | ±1 |
Center point | 15–20 | 0 | 0 | 0 |
Axial | 9–14 | 0, ±1.414 | 0, ±1.414 | 0, ±1.414 |
Mix no. | X1 (w/b) | X2 (HRWRA) | X3 (B) | Cement (kg/m3) | FA (kg/m3) | SF (kg/m3) | HRWRA (l/m3) | Water (l/m3) | E-shale aggregate | |
---|---|---|---|---|---|---|---|---|---|---|
Coarse | Fine | |||||||||
1 | 0.40 | 1.2 | 550 | 440 | 69 | 41 | 6.6 | 220 | 385 | 613 |
2 | 0.40 | 1.2 | 410 | 328 | 51 | 31 | 4.9 | 164 | 456 | 726 |
3 | 0.40 | 0.3 | 550 | 440 | 69 | 41 | 1.6 | 220 | 388 | 618 |
4 | 0.40 | 0.3 | 410 | 328 | 51 | 31 | 1.2 | 164 | 459 | 730 |
5 | 0.30 | 1.2 | 550 | 440 | 69 | 41 | 6.6 | 165 | 422 | 672 |
6 | 0.30 | 1.2 | 410 | 328 | 51 | 31 | 4.9 | 123 | 484 | 771 |
7 | 0.30 | 0.3 | 550 | 440 | 69 | 41 | 1.6 | 165 | 426 | 678 |
8 | 0.30 | 0.3 | 410 | 328 | 51 | 31 | 1.2 | 123 | 487 | 775 |
9 | 0.42 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 201 | 415 | 661 |
10 | 0.28 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 134 | 461 | 734 |
11 | 0.35 | 1.39 | 480 | 384 | 60 | 36 | 6.7 | 168 | 436 | 695 |
12 | 0.35 | 0.11 | 480 | 384 | 60 | 36 | 0.5 | 168 | 440 | 701 |
13 | 0.35 | 0.75 | 580 | 464 | 73 | 44 | 4.3 | 203 | 391 | 622 |
14 | 0.35 | 0.75 | 380 | 304 | 48 | 29 | 2.9 | 133 | 486 | 773 |
15 | 0.35 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 168 | 438 | 698 |
16 | 0.35 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 168 | 438 | 698 |
17 | 0.35 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 168 | 438 | 698 |
18 | 0.35 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 168 | 438 | 698 |
19 | 0.35 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 168 | 438 | 698 |
20 | 0.35 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 168 | 438 | 698 |
3.3 Casting of Test Specimens
3.4 Testing Procedures
3.5 Phase I: Test Results, Analysis and Discussion
3.5.1 Fresh and Hardened Properties of ESH–LWSCC Mixtures
Mix no. | Slump flow (mm) | V-funnel (s) | J-ring flow (mm) | J-ring height diff (mm) | L-box ratio | Filling capacity (%) | SSR (%) | Compressive strength (MPa) | 28-day Unit weight (kg/m3) | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|
7-days | 28-days | Fresh | Air dry | Oven dry | ||||||||
1 | 850 | 1.6 | 850 | 0 | 1.00 | 100 | 14 | 27 | 36 | 1,800 | 1,688 | 1,650 |
2a
| 810 | 1.2 | 770 | 0 | 1.00 | 100 | 38 | 21 | 28 | 1,826 | 1,700 | 1,645 |
3a
| 530 | 1.8 | 540 | 2 | 0.55 | 58 | 6 | 29 | 40 | 1,840 | 1,728 | 1,672 |
4a
| 535 | 5.6 | 510 | 5 | 0.53 | 58 | 24 | 23 | 31 | 1,850 | 1,740 | 1,690 |
5a
| 640 | 11.1 | 650 | 2 | 0.77 | 76 | 10 | 34 | 48 | 1,859 | 1,747 | 1,690 |
6a
| 625 | 11.9 | 590 | 4 | 0.63 | 67 | 20 | 31 | 43 | 1,866 | 1,754 | 1,707 |
7a
| 365 | 19.7 | 370 | 9 | 0.31 | 29 | 4 | 38 | 51 | 1,873 | 1,761 | 1,704 |
8a
| 380 | 18.5 | 360 | 14 | 0.37 | 31 | 6 | 34 | 46 | 1,751 | 1,611 | 1,566 |
9a
| 810 | 1.4 | 805 | 0 | 1.00 | 100 | 30 | 20 | 28 | 1,770 | 1,658 | 1,573 |
10a
| 395 | 24.0 | 415 | 5 | 0.28 | 31 | 7 | 40 | 53 | 1,807 | 1,667 | 1,623 |
11a
| 820 | 3.2 | 795 | 0 | 1.00 | 100 | 24 | 26 | 40 | 1,817 | 1,684 | 1,630 |
12a
| 390 | 6.0 | 390 | 8 | 0.33 | 29 | 7 | 32 | 46 | 1,779 | 1,652 | 1,603 |
13a
| 595 | 6.5 | 630 | 0 | 0.72 | 73 | 6 | 36 | 51 | 1,892 | 1,765 | 1,729 |
14a
| 755 | 1.9 | 715 | 0 | 1.00 | 100 | 34 | 22 | 31 | 1,742 | 1,630 | 1,601 |
15 | 675 | 3.6 | 680 | 2 | 1.00 | 98 | 13 | 31 | 44 | 1,807 | 1,695 | 1,635 |
16 | 705 | 3.7 | 710 | 2 | 0.98 | 100 | 11 | 34 | 48 | 1,789 | 1,676 | 1,604 |
17 | 685 | 4.0 | 680 | 1 | 1.00 | 99 | 12 | 32 | 44 | 1,779 | 1,667 | 1,611 |
18 | 700 | 3.7 | 700 | 1 | 0.97 | 97 | 13 | 31 | 45 | 1,782 | 1,670 | 1,614 |
19 | 685 | 3.5 | 680 | 1 | 1.00 | 97 | 10 | 33 | 46 | 1,787 | 1,662 | 1,597 |
20 | 705 | 4.1 | 700 | 2 | 0.99 | 99 | 12 | 31 | 43 | 1,800 | 1,675 | 1,625 |
4 Phase II: Influence of Mix Design Parameters and Development of Statistical Models
4.1 Influence of Mix Design Parameters on Fresh and Hardened Properties
4.1.1 Influence on the Slump Flow
4.1.2 Influence on the V-funnel Flow Time
4.1.3 Influence on the L-Box Ratio
4.1.4 Influence on the Segregation Resistance
4.1.5 Influence on Other Properties
4.2 Statistical Evaluation of Test Results
Dependent variable | Source of variation | Statistical parameters | Significant | Contribution (%) | ||||
---|---|---|---|---|---|---|---|---|
DOF | Sum of Square | Mean square | F |
p value | ||||
Slump flow | w/b | 1 | 1.409E+05 | 1.409E+05 | 69.88 | 0.0,001 | Y | 36.0 |
HRWRA | 1 | 2.475E+05 | 2.475E+05 | 122.73 | 0.0001 | Y | 63.2 | |
B | 1 | 3101.39 | 3101.39 | 1.54 | 0.2432 | N | 0.8 | |
V-funnel | w/b | 1 | 571.98 | 571.98 | 192.66 | 0.0001 | Y | 92.3 |
HRWRA | 1 | 46.72 | 46.72 | 15.74 | 0.0027 | Y | 7.5 | |
B | 1 | 1.09 | 1.09 | 0.37 | 0.5574 | N | 0.2 | |
J-ring flow | w/b | 1 | 1.302E+05 | 1.302E+05 | 82.89 | 0.0001 | Y | 36.4 |
HRWRA | 1 | 2.277E+05 | 2.277E+05 | 144.89 | 0.0001 | Y | 63.6 | |
B | 1 | 283.95 | 283.95 | 0.18 | 0.6798 | N | 0.1 | |
J-ring height | w/b | 1 | 70.55 | 70.55 | 45.19 | 0.0001 | Y | 38.6 |
HRWRA | 1 | 103.91 | 103.91 | 66.55 | 0.0001 | Y | 56.9 | |
B | 1 | 8.28 | 8.28 | 5.30 | 0.0441 | Y | 4.5 | |
L-box | w/b | 1 | 0.34 | 0.34 | 35.61 | 0.0001 | Y | 37.5 |
HRWRA | 1 | 0.56 | 0.56 | 58.53 | 0.0001 | Y | 61.6 | |
B | 1 | 7.722E−03 | 7.722E−03 | 0.81 | 0.3896 | N | 0.9 | |
Filling capacity | w/b | 1 | 3663.64 | 3663.64 | 53.31 | 0.0001 | Y | 37.7 |
HRWRA | 1 | 5964.65 | 5964.65 | 86.79 | 0.0001 | Y | 61.4 | |
B | 1 | 87.97 | 87.97 | 1.28 | 0.2843 | N | 0.9 | |
Sieve segregation resistance | w/b | 1 | 464.58 | 464.58 | 31.88 | 0.0001 | Y | 29.9 |
HRWRA | 1 | 357.16 | 357.16 | 24.51 | 0.0003 | Y | 22.9 | |
B | 1 | 734.64 | 7.34.64 | 50.41 | 0.0001 | Y | 47.2 | |
7-Day compressive strength | w/b | 1 | 357.62 | 357.62 | 82.24 | 0.0001 | Y | 69.3 |
HRWRA | 1 | 28.85 | 28.85 | 6.63 | 0.0203 | Y | 5.6 | |
B | 1 | 129.55 | 129.55 | 29.79 | 0.0001 | Y | 25.1 | |
28-Day compressive strength | w/b | 1 | 637.51 | 637.51 | 84.72 | 0.0001 | Y | 69.0 |
HRWRA | 1 | 41.52 | 41.52 | 5.52 | 0.0407 | Y | 4.5 | |
B | 1 | 244.55 | 244.55 | 32.50 | 0.0002 | Y | 26.5 | |
Fresh unit weight | w/b | 1 | 622.78 | 622.78 | 0.70 | 0.4212 | N | 7.4 |
HRWRA | 1 | 683.54 | 683.54 | 0.77 | 0.4001 | N | 8.1 | |
B | 1 | 7092.69 | 7092.69 | 8.01 | 0.0178 | Y | 84.5 | |
28-Day air dry unit weight | w/b | 1 | 75.35 | 75.35 | 0.061 | 0.8093 | N | 0.9 |
HRWRA | 1 | 733.33 | 733.33 | 0.59 | 0.4561 | N | 8.3 | |
B | 1 | 8057.00 | 8057.00 | 6.48 | 0.0244 | Y | 90.9 | |
28-Day oven dry unit weight | w/b | 1 | 546.73 | 546.73 | 0.53 | 0.4852 | N | 6.6 |
HRWRA | 1 | 784.87 | 784.87 | 0.75 | 0.4055 | N | 9.4 | |
B | 1 | 6989.34 | 6989.34 | 6.72 | 0.0269 | Y | 84.0 |
4.3 Mathematical Formulation of ESH–LWSCC Properties
Parameters | Slump flow | V-funnel | J-ring flow | J-ring height | L-box | Filling capacity | SSR |
---|---|---|---|---|---|---|---|
Constant | −2631.74 | 282.93946 | −2803.42 | 130.55 | −10.61 | −1020.89 | −183.568 |
w/b | 14376.546 | −1391.542 | 13859.24 | −479.9 | 48.58 | 4597.46 | 632.705 |
HRWRA | 356.7146 | −32.51110 | 387.503 | −51.01 | 0.77 | 136.18 | 38.001 |
B | 0.95820 | 5.826E−03 | 1.788 | 0.051 | 8.8E−03 | 0.800 | 0.3084 |
w/b × HRWRA | 416.66667 | 59.47019 | 333.333 | 55.55 | 1.16 | 7.820 | 8.2980 |
w/b × B | 1.25000 | −0.13444 | 1.428 | 0.142 | −1.8E−3 | −0.203 | −1.070 |
HRWRA × B | 0.29762 | 9.043E−03 | 0.39683 | 0.023 | 7.3E−04 | 0.0455 | −0.060 |
(w/b)2
| −18735.07 | 1818.468 | −18149.1 | 458.64 | −64.59 | −5369.08 | – |
(HRWRA)2
| −217.9190 | 1.98610 | −259.424 | 9.077 | −0.7061 | −74.20 | – |
(B)2
| −1.925E−3 | 4.035E−05 | −2.6E−03 | −2.8E−5 | −9.5E−6 | −8.35E−4 | – |
R
2
| 0.96 | 0.97 | 0.96 | 0.94 | 0.94 | 0.95 | 0.90 |
Parameters | Comp strength | Fresh unit weight | 28-day air dry weight | 28-day oven dry weight | |
---|---|---|---|---|---|
7-day | 28-day | ||||
Constant | 48.71 | −79.42 | 1697.63 | −11.93 | 1995.35 |
w/b | −109.54 | 319.19 | 973.54 | 3681.54 | 2279.59 |
HRWRA | −3.439 | 3.38 | 527.89 | 724.93 | 563.21 |
B | 0.046 | 0.328 | −1.430 | 2.920 | −4.42 |
w/b × HRWRA | – | −1.038 | −915.71 | −1165.45 | −1082.20 |
w/b × B | – | 0.229 | −5.35 | −5.953 | −4.81 |
HRWRA × B | – | −1.9E−3 | −0.579 | −0.624 | −0.52 |
(w/b)2
| – | −821.05 | 3053.463 | – | 1012.11 |
(HRWRA)2
| – | −4.14 | 58.42 | – | 55.48 |
(B)2
| – | −3.6E−4 | 4.25E−03 | – | 7.12E−03 |
R
2
| 0.88 | 0.93 | 0.73 | 0.56 | 0.75 |
4.4 Repeatability of the Test Parameters
Test method | Mean (n = 6) | SD | COV (%) | Estimated error (95 % CI) | Relative error (%) |
---|---|---|---|---|---|
Slump flow (mm) | 692.50 | 12.55 | 1.8 | 12.26 | 1.8 |
V-funnel (s) | 3.77 | 0.23 | 6.2 | 0.23 | 6.1 |
J-ring flow (mm) | 691.67 | 13.29 | 1.9 | 12.99 | 1.9 |
J-ring height (mm) | 1.50 | 0.55 | 36.5 | 0.54 | 35.7 |
L-box (ratio) | 0.99 | 0.01 | 1.3 | 0.01 | 1.2 |
Filling capacity (%) | 98.33 | 1.21 | 1.2 | 1.18 | 1.2 |
Sieve segregation resistance (%) | 11.83 | 1.17 | 9.9 | 1.14 | 9.7 |
7-Day comp strength (MPa) | 32.00 | 1.26 | 4.0 | 1.24 | 3.9 |
28-Day comp strength (MPa) | 45.00 | 1.79 | 4.0 | 1.75 | 3.9 |
Fresh unit weight (kg/m3) | 1790.67 | 10.78 | 0.6 | 10.54 | 0.6 |
28-Day air dry unit (kg/m3) | 1674.17 | 11.44 | 0.7 | 11.18 | 0.7 |
28-Day oven dry unit (kg/m3) | 1614.33 | 13.85 | 0.9 | 13.53 | 0.8 |
5 Phase III: Optimization-Validation of the Statistical Models and Development of Industrial ESH–LWSCC
5.1 Verification of Statistical Models
Mix no. | X1 (w/b) | X2 (HRWRA) | X3 (B) | Cement (kg/m3) | FA (kg/m3) | SF (kg/m3) | HRWRA (l/m3) | Water (l/m3) | ESH-aggregate (kg/m3) | |
---|---|---|---|---|---|---|---|---|---|---|
Coarse | Fine | |||||||||
ESH1 | 0.4 | 0.60 | 520 | 416 | 65 | 39 | 2.9 | 208 | 400 | 640 |
ESH2 | 0.36 | 0.88 | 430 | 344 | 54 | 32 | 3.6 | 155 | 455 | 733 |
ESH3 | 0.32 | 0.94 | 550 | 440 | 69 | 41 | 4.9 | 176 | 415 | 665 |
ESH4 | 0.37 | 0.30 | 420 | 336 | 53 | 32 | 1.2 | 155 | 462 | 738 |
ESH5 | 0.33 | 1.00 | 450 | 360 | 56 | 34 | 4.2 | 148 | 455 | 730 |
ESH6 | 0.35 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 168 | 438 | 698 |
ESH7 | 0.35 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 168 | 438 | 698 |
ESH8 | 0.35 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 168 | 438 | 698 |
ESH9 | 0.35 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 168 | 438 | 698 |
ESH10 | 0.35 | 0.75 | 480 | 384 | 60 | 36 | 3.6 | 168 | 438 | 698 |
Mix no. | Slump flow (mm) | V-funnel (s) | J-ring Flow (mm) | J-ring height diff (mm) | L-box ratio | Filling capacity (%) | SSR (%) |
---|---|---|---|---|---|---|---|
ESH1 | 688 | 1.6 | 698 | 0.5 | 0.86 | 88 | 13 |
ESH2 | 715 | 2.6 | 698 | 1.5 | 1.00 | 100 | 22 |
ESH3 | 636 | 9.4 | 655 | 1.0 | 0.82 | 82 | 7 |
ESH4 | 562 | 3.7 | 542 | 5.5 | 0.69 | 68 | 19 |
ESH5 | 708 | 5.8 | 695 | 1.5 | 0.95 | 96 | 19 |
ESH6 | 705 | 3.7 | 710 | 2.0 | 0.98 | 100 | 11 |
ESH7 | 685 | 4.0 | 680 | 1.0 | 1.00 | 99 | 12 |
ESH8 | 700 | 3.7 | 700 | 1.0 | 0.97 | 97 | 13 |
ESH9 | 685 | 3.5 | 680 | 1.0 | 1.00 | 97 | 10 |
ESH10 | 705 | 4.1 | 700 | 2.0 | 0.99 | 99 | 12 |
Mix no. | Comp strength | Unit weight (kg/m3) | |||
---|---|---|---|---|---|
7-Day | 28-Day | Fresh | 28-Day air dry | 28-Day oven dry | |
ESH1 | 27 | 38 | 1,806 | 1,702 | 1,630 |
ESH2 | 27 | 39 | 1,781 | 1,675 | 1,611 |
ESH3 | 36 | 50 | 1,853 | 1,733 | 1,688 |
ESH4 | 27 | 37 | 1,782 | 1,662 | 1,616 |
ESH5 | 30 | 44 | 1,797 | 1,692 | 1,622 |
ESH6 | 34 | 48 | 1,789 | 1,676 | 1,604 |
ESH7 | 32 | 44 | 1,779 | 1,667 | 1,611 |
ESH8 | 31 | 45 | 1,782 | 1,670 | 1,614 |
ESH9 | 33 | 46 | 1,787 | 1,662 | 1,597 |
ESH10 | 31 | 43 | 1,800 | 1,675 | 1,625 |
5.2 ESH–LWSCC Mixture Optimization
Slump flow | Slump flow (mm) |
---|---|
SF1 | 550–650 |
SF2 | 660–750 |
SF3 | 760–850 |
Viscosity | T500 (s) | V-funnel (s) |
---|---|---|
VS1/VF1 | ≤2 | ≤8 |
VS2/V2 | >2 | 9–25 |
Passing ability (L-box) | Passing ability ratio (h
2/h
1) |
---|---|
PA1 | ≥0.80 with two rebars |
PA2 | ≥0.80 with three rebars |
Sieve segregation resistance | Segregation resistance (%) |
---|---|
SR1 | ≤20 |
SR1 | ≤15 |
Name of responses | Goal | Lower limit | Upper limit | Lower limit | Upper limit | Lower limit | Upper limit |
---|---|---|---|---|---|---|---|
ESH–LWSCC-1 | ESH–LWSCC-2 | ESH–LWSCC-3 | |||||
Slump flow (mm) | In range | 550 | 650 | 660 | 750 | 760 | 850 |
V-funnel (S) | In range | 4 | 8 | 4 | 8 | 0.0 | 8 |
J-ring flow (mm) | In range | 550 | 650 | 660 | 750 | 760 | 850 |
J-ring height (mm) | Minimize | 0.0 | 14.0 | 0.0 | 14.0 | 0.0 | 14.0 |
L-box ratio (h2/h1) | In range | 0.8 | 1.0 | 0.8 | 1.0 | 0.8 | 1.0 |
Filling capacity (%) | In range | 80 | 100 | 80 | 100 | 80 | 100 |
Sieve segregation (%) | In range | 0.0 | 15 | 0.0 | 15 | 0.0 | 20 |
7-Day comp strength (MPa) | In range | 20 | 40 | 20 | 40 | 20 | 40 |
28-Day comp strength (MPa) | In range | 28 | 53 | 28 | 53 | 28 | 53 |
Fresh unit weight (MPa) | Minimize | 1,742 | 1,892 | 1,742 | 1,892 | 1,742 | 1,892 |
28-Day air dry unit (kg/m3) | In range | 1,611 | 1,765 | 1,611 | 1,765 | 1,611 | 1,765 |
28-Day oven dry unit (kg/m3) | In range | 1,566 | 1,729 | 1,566 | 1,729 | 1,566 | 1,729 |
5.3 Verification Experiment for an Optimum Mix Design
Mix no. | ESH–LWSCC-1 | ESH–LWSCC-2 | ESH–LWSCC-3 | |||
---|---|---|---|---|---|---|
Mix parameters and responses | Opt values and expected response | Experimental results for opt mix proportions | Opt values and expected response | Experimental results for opt mix proportions | Opt values and expected response | Experimental results for opt mix proportions |
w/b | 0.35 | 0.35 | 0.35 | 0.35 | 0.40 | 0.40 |
HRWRA | 0.61 | 0.61 | 0.83 | 0.83 | 0.78 | 0.78 |
B | 476 | 476 | 486 | 486 | 504 | 504 |
Slump flow (mm) | 650 | 645 | 708 | 725 | 760 | 770 |
V-funnel (s) | 4 | 4.9 | 4 | 3.8 | 1.32 | 2.1 |
J-ring flow (mm) | 650 | 635 | 709 | 715 | 765 | 760 |
J-ring height (mm) | 2.2 | 2 | 0.83 | 0 | 0 | 0 |
L-box (%) | 0.91 | 0.87 | 1 | 0.98 | 0.99 | 0.99 |
Filling capacity (%) | 90 | 88 | 99.4 | 98 | 99.99 | 98 |
Sieve segregation (%) | 13.1 | 12.1 | 14 | 13 | 17.75 | 18.5 |
7-Day comp strength (MPa) | 30.2 | 32.2 | 30.6 | 33 | 25.8 | 24.5 |
28-Day comp strength (MPa) | 44.6 | 45.75 | 45.4 | 47.75 | 36.95 | 35.1 |
Fresh unit weight (kg/m3) | 1,784 | 1,810 | 1,791 | 1,763 | 1,790 | 1,780 |
28-Day air dry unit (kg/m3) | 1,688 | 1,653 | 1,695 | 1,708 | 1,689 | 1,650 |
28-Day oven dry unit (kg/m3) | 1,606 | 1,585 | 1,614 | 1,602 | 1,610 | 1,590 |
Desirability | 0.81 | – | 0.86 | – | 0.91 | – |