Yingzi Yang

Fabrication and Performance of All-Solid-State Chloride Sensors in Synthetic Concrete Pore Solutions

One type of all-solid-state chloride sensor was fabricated using a MnO2 electrode and a Ag/AgCl electrode. The potentiometric response of the sensor to chloride in synthetic concrete pore solutions was systematically studied, and the polarization performance was also evaluated. The results show a good linear relationship between the potential reading of the sensor and the logarithm of chloride activity (concentration ranges from 0.05 to 5.0 M), and the potential value remains stable with increasing immersion time. The existence of K+, Ca2+, Na+ and SO42− ions have little influence on the potentiometric response of the sensor to chloride, but the pH has a significant influence on the potential value of the sensor at low chloride concentration. The potential reading of the sensor increases linearly with the solution temperature over the range from 5 to 45 °C. Meanwhile, an excellent polarization behavior is proven by galvanostatic and potentiodynamic tests. All of the results reveal that the developed sensor has a great potential for monitoring chloride ions in concrete environments.

Influence of curing temperature on flexural performance of engineered cementitious composites

In order to investigate the effects of different curing temperatures on the flexural performance of engineered cementitious composites (ECC), the four-point bending test is employed in this paper. Four curing temperatures are applied to the ECC specimens, which are 20°C, 40°C, 60°C and 80°C, respectively. The experimental result indicates that the deflection of ECCs at early age decreases gradually as the curing temperature increases. However, the deflection and toughness index of ECCs have no significant change as the curing temperature is above 40°C at later age.