| In view of the deficiency of concrete energy spectrum,XRD diffraction and other damage detection,in this paper,hyperspectral technology is used to study the conditions of hyperspectral measurement and the applicability of spectral unmixing for concrete hydration products.Samples from 1 to 150 days of cement paste,cement mortar and concrete test blocks were selected as the observation objects.The experimental study on hyperspectral measurement and spectral analysis of concrete samples under different ages,different observation surfaces and different dry states was conducted respectively.The spectral curves of the mixture of calcium hydroxide and calcium sulfate with different proportions were measured.The calcium hydroxide in the solid mixture was demixed by the ratio derivative method,and the applicability of the ratio derivative method to the spectral demixing of concrete hydration products was analyzed.The results show that the overall trend of the spectral curves of cement paste,cement mortar and concrete specimen is basically the same.However,the spectral parameters such as the depth and width of the absorption peak are different,and the upper surface of the test sample is suitable to be the standard observation surface for preliminary hyperspectral nondestructive testing.The experimental results of spectral unmixing of calcium hydroxide and calcium sulfate mixture show that the strong linear band of calcium hydroxide is near 1380 nm and 2420 nm,and there is a high correlation between the specific value of mixture and the actual abundance of calcium hydroxide.The ratio derivative method is used to carry out quantitative analysis of calcium hydroxide in concrete hydration products.The results of hyperspectral demixing analysis of samples of different ages are more than that of samples of 60 d,which has certain reference value for the detection of actual concrete hydration degree and the accurate extraction of hydration products.Figure 36;Table 30;Reference 75... |
PDF Full Text Request