基于电化学阻抗谱的矿物掺合料混凝土水泥水化过程研究

Study on the cement hydration processes of concrete with mineral admixures based on electrochemical impedance spectroscopy

采用电化学阻抗谱方法对掺入粉煤灰或矿渣的混凝土水泥水化过程进行了研究,从不同龄期混凝土电化学阻抗谱的特征出发,分析了矿物掺合料对混凝土中水泥水化过程的电化学阻抗参数的影响,讨论了混凝土结构的变化与发展.研究表明:不同粉煤灰或矿渣掺量的混凝土电化学阻抗谱具有相同的变化趋势.在水化早期,随着矿物掺合料掺量的增大,阻抗参数sR、ctR和?减小,混凝土的总孔隙率增大,结构变疏松;水化后期,由于矿物掺合料的二次水化作用,阻抗参数sR、ctR和?逐渐增大,混凝土的总孔隙率减小,结构变密实,且随矿物掺合料掺量的增加混凝土细观结构的密实度越高.

The cement hydration of concrete mixed with fly ash or slag was studied by means of the electrochemical impedancespectroscopy. Starting with the characteristics of electrochemical impedance spectrum, the influence of the mineral admixtures onelectrochemical impedance parameters in the concrete cement hydration process was analyzed and the development and changes ofthe concrete structure was discussed. The results show the concrete electrochemical impedance spectroscopy with different quantityof fly ash or slag is the same in trend. During the earlyst age of hydration, the impedance parameters s R , ct R and ? reduced andthe total porosity of the concrete increased with the increases of the amount of mineral admixtures incorporated in concrete and thestructure of concrete becomes loose. In the latest age of hydration, the impedance parameters s R , ct R and ? gradually increasebecause of the secondary hydration effects and the total porosity of the concrete decreased and the structure of concrete becomescompacted, and with the increase of mineral admixture content, the meso-structures of concrete becomes more compact.