Effects of sodium carbonate on self-healing properties of cement-slag-limestone powder ternary cementitious material

초록

Cement-slag-limestone ternary cementitious materials are cement-based materials with signifi-cant potential for applications, it exhibits extremely low carbon emissions and excellent work-ability. Now, to lower CO2 emissions of concrete industry the use of ternary blends is gradually popularized, and the investigation of their self-healing properties of it is of interest to the con-struction industry. So far, the effect of sodium carbonate on the self-healing of cement-slag -limestone ternary cementitious materials is not clear. In this study, we prepared ternary blends with different concentrations of sodium carbonate (0 %, 2.5 %, and 5 %) were prepared. And systematically investigated the self-healing ability of the samples through a combined macro -microscopic experimental method. Macroscopic aspects: The compressive strength of the sam-ples was tested after 28 days of curing, and the changes in the crack width and relative perme-ability coefficients were recorded during the self-healing period. Microscopic aspects: The samples were examined for calcium and sodium ion leaching using an inductively coupled plasma optical emission spectrometer. The crack interiors were observed using a scanning electron mi-croscope. And the healing compounds were tested using X-ray diffraction and attenuated total reflection Fourier transform infrared spectroscopy. The result shows, sodium carbonate reduced the 28-day compressive strength of the slurries and the number of leached calcium ions. The addition of 2.5 % sodium carbonate promoted the early permeability resistance repair of the ternary cement, and the addition of 5 % sodium carbonate reduced the self-healing ability of the ternary cement.

키워드