# Study on Microwave Deicing of Carbon-Fiber-Modified Concrete under Multi-Factor Coupling Effect
## 3 Results
### Effect of Initial Temperature on Deicing  
With a height of 20 mm and after continuous irradiation for 120 s, 0.6 CFC3 carbon fiber concrete specimens were tested at \(-\)10 \({}^{\circ}\)C, \(-\)6 \({}^{\circ}\)C and \(-\)2 \({}^{\circ}\)C; the temperature changes of each specimen are shown in Figure 10.  
It can be seen from the Figures 10 and 11 that (1) when the initial temperature was \(-\)10 \({}^{\circ}\)C, \(-\)6 \({}^{\circ}\)C and \(-\)2 \({}^{\circ}\)C, the final temperature of the central point (T\({}_{0}\)) after microwave heating for 120 s was 17.2 \({}^{\circ}\)C, 24.9 \({}^{\circ}\)C and 26.3 \({}^{\circ}\)C, respectively. The time for the temperature of the central point (T\({}_{0}\)) on the surface of the specimen to reach 0 \({}^{\circ}\)C was 40 s, 33 s and 24 s, respectively. This indicates that the higher the initial temperature, the shorter the time for the specimen to reach 0 \({}^{\circ}\)C, the shorter the deicing time and the faster the deicing speed. The deicing speed of the specimen at \(-\)2 \({}^{\circ}\)C was about 1.7 times of that at \(-\)10 \({}^{\circ}\)C. (2) When the initial temperature was \(-\)10 \({}^{\circ}\)C, \(-\)6 \({}^{\circ}\)C and \(-\)2 \({}^{\circ}\)C, the deicing areas were 163.73 cm\({}^{2}\), 181.45 cm\({}^{2}\) and 232.93 cm\({}^{2}\), respectively. With a higher initial temperature, the deicing area was larger with the same deicing time. When the initial temperature was 2 \({}^{\circ}\)C, the deicing area was significantly larger than with an initial temperature of \(-\)10 \({}^{\circ}\)C of 6 \({}^{\circ}\)C; this is because the initial temperature not only improves the center of the specimen surface (T\({}_{0}\)) but also the initial temperature of the ice. Therefore, a higher initial temperature can  
Figure 10: Temperature changes of each specimen at different initial temperatures. (a) \(-\)10 \({}^{\circ}\)C; (b) \(-\)6 \({}^{\circ}\)C; (c) \(-\)2 \({}^{\circ}\)C.  
significantly increase the efficiency of deicing. (3) When the initial temperature was \(-10\)\({}^{\circ}\)C, the temperature at the center point (T\({}_{0}\)) on the surface of the specimen reached 0 \({}^{\circ}\)C after heating for 40 s, with no plateau near 0 \({}^{\circ}\)C on the temperature increase curve, and the last ice sheet did not break, indicating that the temperature increase rate in the central region was fast, and the initial melting area was small. Once the temperature reached 0 \({}^{\circ}\)C, a water layer formed quickly and melted the ice sheet, acting as a heat source. However, because the heat is spread more sideways than upward, the ice did not break, and there was no fluctuation in the rate of temperature increase. (4) When the initial temperature was \(-6\)\({}^{\circ}\)C, the temperature increase curve of the central point (T\({}_{0}\)) reached 0 \({}^{\circ}\)C after 33 s of heating, and there was no plateau at 0 \({}^{\circ}\)C, indicating that a water layer formed quickly. With a higher initial temperature, the ice is easier to melt, and it takes less time to reach 0 \({}^{\circ}\)C, so the temperature of the central point (T\({}_{0}\)) remains near 20 \({}^{\circ}\)C for a long time after 60 s of heating. A plateau appeared in the temperature increase curve, and the temperature increase rate reached its lowest value, indicating that the ice broke at this time and that the temperature increase rate sharply decreased before ice breaking, which is consistent with the previous theoretical derivation. In conclusion, varying initial temperatures have a similar effect as different starting points of the same heating process. Because the initial temperature affects the temperature of the ice, the higher the initial temperature, the smaller the temperature difference between the ice, water layer and concrete and the shorter the deicing time.