Carbonation Resistance of Marine Concrete Containing Nano-SiO<sub>2</sub> under the Action of Bending Load
In order to study the influence of nanomaterials on the carbonation resistance of marine concrete under bending loads, an appropriate amount of nano-SiO<sub>2</sub> was added to plain concrete, and a self-developed carbonation box and bending loading device were used to conduct a couplin...
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MDPI AG
2023-03-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/11/3/637 |
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| author | Maohua Zhang Zenong Tian Jiyin Cui |
| author_facet | Maohua Zhang Zenong Tian Jiyin Cui |
| author_sort | Maohua Zhang |
| collection | DOAJ |
| description | In order to study the influence of nanomaterials on the carbonation resistance of marine concrete under bending loads, an appropriate amount of nano-SiO<sub>2</sub> was added to plain concrete, and a self-developed carbonation box and bending loading device were used to conduct a coupling test. Four different stress levels were set to measure the carbonation depth of nano-concrete at different ages. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to analyze the concrete interfacial transition zone. The carbonation depth was used as the test index to evaluate the durability of nano-SiO<sub>2</sub>-based concrete under the combined action of bending load and carbonation. The test results showed that the compressive and flexural strengths of concrete remarkably improved when the nano-SiO<sub>2</sub> concentration was 2%. Compared with regular concrete, the compressive and flexural strengths of nano-SiO<sub>2</sub> based concrete improved by 15.5% and 15.3%, respectively. When the stress level was 0.15 and 0.6, the carbonation depths of NS20 were 20.5 and 18.4% lower than those of PC in the tensile zone and 18.9 and 23.7% lower than those of PC in the compression zone. The carbonation depth of the NS20 tensile zone was lower by 31 and 18.4% at 3 and 28 days than that of PC. Compared with PC, the carbonation depth in the compression zone of NS20 decreased by 50 and 23.7%, and the carbonation depth of nano-concrete was significantly lower than that of conventional concrete under the same stress level and age. When the stress level is constant, the carbonation depth of the tension zone and compression zone increases gradually with the increase in age, and the carbonation depth of the concrete in the first 7 d was 50% that at 28 days. Under the same age, the carbonation depth in the tension zone increased with increasing stress levels, while the carbonation depth in the compression zone decreased with increasing stress levels. When the stress level was 0.3–0.45, the slope of the carbonation depth curve significantly increased. SEM and XRD analysis results revealed that nano-SiO<sub>2</sub> significantly improved the internal structure of concrete by reducing the width of the microcracks, the number of pores, and the number of microcracks. The number of C<sub>3</sub>S/C<sub>2</sub>S and CaCO<sub>3</sub> crystals in nano-SiO<sub>2</sub> based concrete was significantly less than that in plain concrete, and the amount of C-S-H gel was more than that in plain concrete. Under bending loads, the nano-SiO<sub>2</sub> significantly improved the carbonation resistance of concrete. When the dosage of nano-SiO<sub>2</sub> was 2%, its improvement effect was the most significant. |
| first_indexed | 2024-03-11T06:20:33Z |
| format | Article |
| id | doaj.art-ddc17b3437524a39988cdf008d391340 |
| institution | Directory Open Access Journal |
| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-03-11T06:20:33Z |
| publishDate | 2023-03-01 |
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| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-ddc17b3437524a39988cdf008d3913402023-11-17T11:58:23ZengMDPI AGJournal of Marine Science and Engineering2077-13122023-03-0111363710.3390/jmse11030637Carbonation Resistance of Marine Concrete Containing Nano-SiO<sub>2</sub> under the Action of Bending LoadMaohua Zhang0Zenong Tian1Jiyin Cui2School of Civil Engineering, Northeast Forestry University, Harbin 150040, ChinaSchool of Civil Engineering, Northeast Forestry University, Harbin 150040, ChinaSchool of Civil Engineering, Northeast Forestry University, Harbin 150040, ChinaIn order to study the influence of nanomaterials on the carbonation resistance of marine concrete under bending loads, an appropriate amount of nano-SiO<sub>2</sub> was added to plain concrete, and a self-developed carbonation box and bending loading device were used to conduct a coupling test. Four different stress levels were set to measure the carbonation depth of nano-concrete at different ages. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to analyze the concrete interfacial transition zone. The carbonation depth was used as the test index to evaluate the durability of nano-SiO<sub>2</sub>-based concrete under the combined action of bending load and carbonation. The test results showed that the compressive and flexural strengths of concrete remarkably improved when the nano-SiO<sub>2</sub> concentration was 2%. Compared with regular concrete, the compressive and flexural strengths of nano-SiO<sub>2</sub> based concrete improved by 15.5% and 15.3%, respectively. When the stress level was 0.15 and 0.6, the carbonation depths of NS20 were 20.5 and 18.4% lower than those of PC in the tensile zone and 18.9 and 23.7% lower than those of PC in the compression zone. The carbonation depth of the NS20 tensile zone was lower by 31 and 18.4% at 3 and 28 days than that of PC. Compared with PC, the carbonation depth in the compression zone of NS20 decreased by 50 and 23.7%, and the carbonation depth of nano-concrete was significantly lower than that of conventional concrete under the same stress level and age. When the stress level is constant, the carbonation depth of the tension zone and compression zone increases gradually with the increase in age, and the carbonation depth of the concrete in the first 7 d was 50% that at 28 days. Under the same age, the carbonation depth in the tension zone increased with increasing stress levels, while the carbonation depth in the compression zone decreased with increasing stress levels. When the stress level was 0.3–0.45, the slope of the carbonation depth curve significantly increased. SEM and XRD analysis results revealed that nano-SiO<sub>2</sub> significantly improved the internal structure of concrete by reducing the width of the microcracks, the number of pores, and the number of microcracks. The number of C<sub>3</sub>S/C<sub>2</sub>S and CaCO<sub>3</sub> crystals in nano-SiO<sub>2</sub> based concrete was significantly less than that in plain concrete, and the amount of C-S-H gel was more than that in plain concrete. Under bending loads, the nano-SiO<sub>2</sub> significantly improved the carbonation resistance of concrete. When the dosage of nano-SiO<sub>2</sub> was 2%, its improvement effect was the most significant.https://www.mdpi.com/2077-1312/11/3/637marine concretenano-SiO<sub>2</sub>bending loadcarbonationdurabilitymicrostructure |
| spellingShingle | Maohua Zhang Zenong Tian Jiyin Cui Carbonation Resistance of Marine Concrete Containing Nano-SiO<sub>2</sub> under the Action of Bending Load Journal of Marine Science and Engineering marine concrete nano-SiO<sub>2</sub> bending load carbonation durability microstructure |
| title | Carbonation Resistance of Marine Concrete Containing Nano-SiO<sub>2</sub> under the Action of Bending Load |
| title_full | Carbonation Resistance of Marine Concrete Containing Nano-SiO<sub>2</sub> under the Action of Bending Load |
| title_fullStr | Carbonation Resistance of Marine Concrete Containing Nano-SiO<sub>2</sub> under the Action of Bending Load |
| title_full_unstemmed | Carbonation Resistance of Marine Concrete Containing Nano-SiO<sub>2</sub> under the Action of Bending Load |
| title_short | Carbonation Resistance of Marine Concrete Containing Nano-SiO<sub>2</sub> under the Action of Bending Load |
| title_sort | carbonation resistance of marine concrete containing nano sio sub 2 sub under the action of bending load |
| topic | marine concrete nano-SiO<sub>2</sub> bending load carbonation durability microstructure |
| url | https://www.mdpi.com/2077-1312/11/3/637 |
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