Table 1:
The physical properties of the used cement
| Property | Test result (%) | Standard IQS, No.5 |
|---|---|---|
| Initial setting time [min.] | 105 | ≥45 [min.] |
| Final setting time [min.] | 285 | ≤600 [min.] |
| Compressive strength [MPa] | ||
| at 2 days | 20.3 | ≥15.0 [MPa] |
| at 7 days | 26.5 | ≥23.0 [MPa] |
Table 2:
The chemical composition of the used cement
| Property | Test result (%) | Standard IQS, No. 5 |
|---|---|---|
| Oxide composition | ||
| Alumina, Al2O3 | 4.16 | |
| Silica, Sio2 | 21 | |
| Ferric oxide, Fe2O3 | 2.01 | |
| Lime, CaO | 59.1 | |
| Sulphuric anhydride, SO3 | 1.57 | Max. 2.5 |
| Magnesium, MgO | 2.95 | Max. 5 |
| Compound composition | ||
| C3A | 7.64 | |
| C2S | 31.03 | |
| C3S | 38.68 | |
| C4AF | 6.10 | |
| Free lime | 1.27 | |
| Loss on ignition | 0.8 | Max. 4 |
| Solid solution | 12.16 | |
| Insoluble residue | 0.95 | |
Table 3:
The Sieve analysis of the used sand and the recycled fine aggregate
| Sieve size (mm) | % specification limits | NFA 0%FRA | FRA |
|---|---|---|---|
| 4.75 | 95–100 | 100 | 100 |
| 2.36 | 80–100 | 86.9 | 80.6 |
| 1.18 | 50–85 | 72.4 | 57.5 |
| 600μm | 25–60 | 55.5 | 40.3 |
| 300μm | 5–30 | 23.6 | 22 |
| 150μm | 0–10 | 5.8 | 8.2 |
Table 4:
The physical properties of the sand and the recycled fine aggregate
| Type of fine aggregate | NFA | FRA |
|---|---|---|
| Colour | Brown | Gray |
| Bulk specific gravity [SSD] | 2.64 | 2.35 |
| Absorption [%] | 2 | 8% |
| Compact unit weight [kg/m3] | 1858 | 1444 |
| Loose unit weight [kg/m3] | 1722 | 1349 |
Figure 1:
The recycled fine aggregate
Table 5:
Grading of normal coarse aggregate
| Sieve size (mm) | % Specification limits | % Passing of used sample |
|---|---|---|
| 25 | 100 | 100 |
| 19 | 90–100 | 100 |
| 9.5 | 20–55 | 40 |
| 4.75 | 0–10 | 0 |
Table 6:
Properties of coarse aggregate
| Type of coarse aggregate | Rounded gravel |
|---|---|
| Specific gravity S.S. D | 2.72 |
| Absorption [%] | 0.45 |
| Compact unit weight [kg/m3] | 1730 |
| Loose unit weight [kg/m3] | 1650 |
Table 7:
Chemical composition of eggshell powder
| Property | Test result (%) |
|---|---|
| Oxide composition | |
| Alumina, Al2O3 | 1.19 |
| Silica, SiO2 | 1.77 |
| Ferric oxide, Fe2O3 | 0.91 |
| Lime, CaO | 97.70 |
| Sulphuric anhydride, SO3 | 0.53 |
| Magnesium, MgO | 0.07 |
Figure 2:
The process of preparing eggshell powder
Table 8:
Concrete mix details (kg per cubic meter)
| Mix | FRA (%) | EGP (%) | Cement | Sand | Gravel | FRA | EGP | Water |
|---|---|---|---|---|---|---|---|---|
| M1 | 0 | 0 | 374 | 750 | 1054 | 0 | 0 | 187 |
| M2 | 0 | 5 | 355.3 | 750 | 1054 | 0 | 18.7 | 187 |
| M3 | 0 | 10 | 336.6 | 750 | 1054 | 0 | 37.4 | 187 |
| M4 | 10 | 0 | 374 | 688 | 1054 | 62 | 0 | 187 |
| M5 | 10 | 5 | 355.3 | 688 | 1054 | 62 | 18.7 | 187 |
| M6 | 10 | 10 | 336.6 | 688 | 1054 | 62 | 37.4 | 187 |
| M7 | 20 | 0 | 374 | 626 | 1054 | 124 | 0 | 187 |
| M8 | 20 | 5 | 355.3 | 626 | 1054 | 124 | 18.7 | 187 |
| M9 | 20 | 10 | 336.6 | 626 | 1054 | 124 | 37.4 | 187 |
| M10 | 30 | 0 | 374 | 564 | 1054 | 186 | 0 | 187 |
| M11 | 30 | 5 | 355.3 | 564 | 1054 | 186 | 18.7 | 187 |
| M12 | 30 | 10 | 336.6 | 564 | 1054 | 186 | 37.4 | 187 |
Figure 3:
Experimental program flowchart
Figure 4:
The slump test results for all concrete mixes
Figure 5:
Compaction factor test
Figure 6:
Effect of adding varying percentages of recycled fine aggregate and eggshell powder on the compaction factor
Figure 7:
The slump loss in concrete mixes containing recycled fine aggregate and eggshell powder
Figure 8:
The fresh density values of concrete mixes containing recycled fine aggregate and eggshell powder
Figure 9:
The compressive strength values of the concrete mixes used at different ages (7, 28, and 56 days)
Figure 10:
The effect of adding eggshell powder on the compressive strength of concrete mixes that do not contain recycled aggregate
Figure 11:
The effect of adding eggshell powder and recycled aggregate on the tensile strength of the concrete mixes
Figure 12:
The effect of adding eggshell powder and recycled aggregate on the ultrasonic pulse velocity values of the concrete mixes
Table 9:
Concrete classification (Evangelista & Guedes, 2019)
| Pulse velocity [km/s] | Concrete classification |
|---|---|
| V > 4.5 | Excellent |
| 4.5 > V > 3.5 | Good |
| 3.5 > V > 3.0 | Questionable |
| 3.0 > V > 2.0 | Poor |
| V <2.0 | Very poor |
Figure 13:
Effect of adding eggshell powder and recycled aggregate on the absorption values of the concrete mixes