Use of ZnAl-Layered Double Hydroxide (LDH) to Extend the Service Life of Reinforced Concrete
Abstract
:1. Introduction
2. Materials and Methods
2.1. Synthesis of ZnAl-NO3 and ZnAl-NO2 LDHs
2.2. Structure and Morphology of the ZnAl LDH
2.3. Stability of ZnAl LDH in Aqueous Solution
2.4. Ion Exchange in Aqueous Solution
2.5. Effect of ZnAl LDH on the Corrosion of Steel in Aqueous Solutions
2.6. Cement Pastes and Mortars Preparation
2.7. Chloride Sensors inside Mortars
2.8. Impact of ZnAl LDH on the Corrosion of Steel Rebars in Mortars
3. Results and Discussion
3.1. Structure and Morphology of the Synthesized ZnAl LDHs
3.2. Stability of ZnAl LDH in Aqueous Solution
3.3. The Capacity of ZnAl LDH for Capturing Chloride Ions
3.4. Effect of ZnAl LDH on the Corrosion of Steel in Aqueous Solution
3.5. Influence of ZnAl LDH on the Hardening of Cement Paste
3.6. Impact of ZnAl LDH on the Corrosion of Steel Rebars in Mortars
3.6.1. Chloride Sensors inside Mortar
3.6.2. Electrochemical Impedance Spectroscopy
3.7. Final Remarks
4. Conclusions
Author Contributions
Funding
Conflicts of Interest
References
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pH | Composition | Time | Rs (Ω cm2) | Y0,pass (F cm−2 sn−1) | npass | Cpass (μF cm−2) | Rpass (Ω cm2) | Y0,dl (F cm−2 sn−1) | ndl | Cdl (μF cm−2) | Rct (Ω cm2) | Χ2/10−4 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
13 | Blank | 1d | 6.7 | 3.07 × 10−5 | 0.968 | 23.1 | 50.53 | 6.86 × 10−6 | 0.701 | 0.23 | 1.09 × 106 | 0.83 |
3d | 6.9 | 3.55 × 10−5 | 0.946 | 22.1 | 80200 | 9.44 × 10−6 | 0.794 | 8.69 | 2.00 × 106 | 0.37 | ||
7d | 9.8 | 3.45 × 10−5 | 0.917 | 16.7 | 81882 | 1.14 × 10−5 | 0.793 | 11.1 | 3.87 × 106 | 0.36 | ||
14d | 11.7 | 2.76 × 10−5 | 0.921 | 13.8 | 220140 | 5.95 × 10−6 | 0.740 | 6.52 | 4.27 × 107 | 0.27 | ||
0.5% LDH-NO2 | 1d | 8.0 | 3.17 × 10−5 | 0.945 | 19.6 | 19353 | 8.37 × 10−6 | 0.680 | 3.53 | 1.34 × 106 | 0.13 | |
3d | 8.2 | 3.16 × 10−5 | 0.950 | 20.4 | 19250 | 8.91 × 10−6 | 0.676 | 3.81 | 2.47 × 106 | 0.25 | ||
7d | 8.9 | 3.29 × 10−5 | 0.947 | 20.9 | 28134 | 1.03 × 10−5 | 0.701 | 6.02 | 3.98 × 106 | 0.39 | ||
14d | 11.3 | 3.24 × 10−5 | 0.950 | 21.4 | 54358 | 6.03 × 10−6 | 0.650 | 3.32 | 1.80 × 107 | 0.34 | ||
6 | Blank | 1h | 37.3 | − | − | − | − | 1.11 × 10−3 | 0.708 | 294 | 1049 | 3.9 |
2d | 35.5 | − | − | − | − | 1.84 × 10−3 | 0.750 | 730 | 938 | 8.8 | ||
30d | 38.0 | − | − | − | − | 4.00 × 10−3 | 0.600 | 1085 | 500 | 10 | ||
0.5% LDH-NO2 | 1h | 33.4 | 2.93 × 10−5 | 0.867 | 10.1 | 5063 | 3.46 × 10−6 | 0.925 | 2.50 | 1.21 × 106 | 4.2 | |
20h | 31.2 | 2.20 × 10−5 | 0.870 | 7.41 | 92184 | 2.27 × 10−6 | 0.898 | 1.89 | 5.30 × 106 | 3.4 | ||
2d | 34.5 | 1.86 × 10−5 | 0.878 | 6.70 | 67366 | 3.44 × 10−6 | 0.814 | 2.45 | 9.21 × 106 | 1.4 | ||
30d | 30.0 | 2.50 × 10−5 | 0.868 | 8.37 | 9089 | 3.40 × 10−6 | 0.915 | 2.46 | 1.30 × 106 | 4 | ||
0.5% LDH-NO3 | 1h | 32.5 | 3.22 × 10−4 | 0.645 | 16.2 | 23.5 | 6.82 × 10−4 | 0.595 | 40.4 | 1347 | 3 | |
2d | 35.0 | 1.84 × 10−3 | 0.681 | 381 | 41.1 | 2.43 × 10−3 | 0.733 | 940 | 925 | 1.4 | ||
30d | 35.5 | 1.92 × 10−3 | 0.680 | 382 | 32 | 2.89 × 10−3 | 0.707 | 1063 | 1002 | 8 |
System | Time | Rpore (Ω cm2) | Y0,pass (F cm−2 sn−1) | npass | Cpass (μF cm−2) | Rpass (Ω cm2) | Y0,dl (F cm−2 sn−1) | ndl | Cdl (μF cm−2) | Rct (Ω cm2) | Χ2/10−4 |
---|---|---|---|---|---|---|---|---|---|---|---|
Reference | 1d | 851 | 4.30 × 10−5 | 0.980 | 40.2 | 802721 | − | − | − | − | 2.1 |
4d | 518 | 1.19 × 10−4 | 0.810 | 61.6 | 30565 | 1.85 × 10−4 | 0.598 | 409 | 4.22 × 104 | 5 | |
21d | 589 | 1.24 × 10−4 | 0.845 | 75.2 | 6515 | 2.50 × 10−4 | 0.636 | 293 | 2.80 × 104 | 0.9 | |
69d | 661 | 1.59 × 10−4 | 0.774 | 78.6 | 3860 | 7.73 × 10−4 | 0.615 | 1457 | 4.61 × 104 | 1 | |
LDH-NO3 | 19d | 468 | 1.07 × 10−4 | 0.854 | 63.9 | 75078 | 2.04 × 10−4 | 0.902 | 260 | 1.21 × 105 | 16 |
28d | 524 | 1.22 × 10−4 | 0.790 | 58.2 | 39152 | 2.88 × 10−5 | 0.942 | 28.3 | 8.47 × 104 | 1.8 | |
72d | 481 | 1.97 × 10−4 | 0.730 | 81.4 | 15423 | 5.42 ×10−5 | 0.460 | 43.3 | 1.12 × 106 | 2.4 | |
LDH-NO2 | 4d | 474 | 5.17 × 10−5 | 0.987 | 49.2 | 998436 | − | − | − | − | 2 |
13d | 444 | 1.12 × 10−4 | 0.876 | 73.3 | 402510 | − | − | − | − | 3 | |
20d | 491 | 1.37 × 10−4 | 0.827 | 77.4 | 17441 | 4.56 × 10−5 | 0.658 | 36.5 | 8.00 × 104 | 0.7 | |
64d | 450 | 1.63 × 10−4 | 0.808 | 86.9 | 15241 | 3.40 × 10−6 | 0.936 | 40.2 | 1.79 × 105 | 0.8 |
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Share and Cite
Gomes, C.; Mir, Z.; Sampaio, R.; Bastos, A.; Tedim, J.; Maia, F.; Rocha, C.; Ferreira, M. Use of ZnAl-Layered Double Hydroxide (LDH) to Extend the Service Life of Reinforced Concrete. Materials 2020, 13, 1769. https://doi.org/10.3390/ma13071769
Gomes C, Mir Z, Sampaio R, Bastos A, Tedim J, Maia F, Rocha C, Ferreira M. Use of ZnAl-Layered Double Hydroxide (LDH) to Extend the Service Life of Reinforced Concrete. Materials. 2020; 13(7):1769. https://doi.org/10.3390/ma13071769
Chicago/Turabian StyleGomes, Celestino, Zahid Mir, Rui Sampaio, Alexandre Bastos, João Tedim, Frederico Maia, Cláudia Rocha, and Mário Ferreira. 2020. "Use of ZnAl-Layered Double Hydroxide (LDH) to Extend the Service Life of Reinforced Concrete" Materials 13, no. 7: 1769. https://doi.org/10.3390/ma13071769