Futian Liu

Piezoelectric properties of 0-3 PZT/sulfoaluminate cement composites

A sulfoaluminate cement was, for the first time, used to fabricate 0-3 piezoelectric composites by a compressing technique. The dependences of the piezoelectric properties of composites on the content of PZT and poling conditions are discussed. The results show that the piezoelectric properties of composites are improved by increasing the poling field E and poling time t, but when E and t exceeded 4.0 kV mm−1 and 45 min, d33 tends to be constant. The piezoelectric constants and the electromechanical coupling coefficients Kp, Kt of composites increase rapidly with increasing the content of PZT. When the content of PZT reaches 85%, Kp and Kt are 28.54% and 28.19%, respectively.

Influence of fluorite on the Ba-bearing sulphoaluminate cement

Abstract In this paper, minorcompounds CaF2, MnO2, MgO, and P2O5 were mixed into the raw meals of 2.75CaO·1.25BaO·3Al2O3·CaSO4 (abbr. C2.75B1.25A3S) that were burned under different temperatures and treating times. The strength was determined. Through the orthogonal experiment, we found that the mineral is of optimal strength when containing 1.4% CaF2 and treated 2 h at 1350°C. Based on this conclusion, the Ba-bearing sulphoaluminate cement has been burned with Ba-bearing industrial wastes and fluorite. In addition, the hydration mechanism of the cement was analyzed.

Dielectric and piezoelectric properties of piezoelectric ceramic–sulphoaluminate cement composites

Using cement as the matrix of piezoelectric smart composites can solve the problem of mismatch of smart composites and concrete structure in civil engineering. 0–3 cement based piezoelectric composites were fabricated by a compression technique using PMN and sulphoaluminate cement as raw materials. The influence of the PMN content on the dielectric and piezoelectric properties of the composites was investigated. The temperature dependence of the dielectric properties of the composites was discussed in detail. The results indicate that the dielectric constants are almost constant in the temperature range from −30 to 50 °C, which shows excellent dielectric–temperature stability. With increasing PMN content, the piezoelectric and dielectric properties of the composites increase. The theoretical values of the dielectric constants show good agreement with the experimental values for the composites.

The influences of two admixtures on white and colored Portland cement

This paper studies the influence of two admixtures on white and colored Portland cement. The results show that the compressive strength of the white Portland cement is improved when the proper quantity of the admixtures is mixed, and the white degree of the white Portland cement is obviously not influenced. In addition, the cost of the white Portland cement is reduced and the color of the colored Portland cement is ameliorated. Through the experiment, the optimal quantity of the admixtures is found. The hydration mechanism of the cement and the reason of improving color are discussed by XRD, TG, SEM and so on.