In order to reveal the changes in the pore structure of concrete of different strengths at low temperatures and construct a theoretical framework for pore evolution of plain concrete at low temperatures,tested with NMR testing equipment,focusing on the pore structure characteristic parameters such as porosity,T2 spectra,and main peak area of concrete specimens,the test results show that T2 spectra of plain concrete specimens at different temperatures show fluctuations of three peaks;as the temperature decreases,the wave peaks of the T2 spectra of concrete specimens of different strengths shift to the left;the porosity of the concrete specimens also decreased with decreasing temperature;the peak area of the first peak is much larger than the peak areas of the other two peaks;under low-temperature freezing,the pore size distribution of C30,C40,and C50 concrete is predominantly in the range of 0.001～1 μm;more than 95%are micropores and mesopores.
关键词
混凝土/核磁共振/低温/孔隙度
Key words
concrete/nuclear magnetic resonance/low temperatures/porosity
维普
万方数据