The authors provide very useful modification of the existing cement grouting technique for civil engineering purposes. However, two critical issues are remarked by the discussers in the description of the Bender Element (BE) testing recorded in the paper, including (1) the bender elements tip-to-tip wavelength to the excitation frequency (Ltt/λ) ratio; (2) calibration of the bender elements. This discussion considers that the cement grouted soil has similar stiffness characteristics with the cement mixed soil.
Moon, S-W., Zhanar, B., Khan, Q., & Ku, T. (2019). Discussion on “Shear wave velocity of zeolite-cement grouted sands”, by Afshin Kordnaeij, Reza Ziaie Moayed and Majid Soleimani [Soil Dyn Earthq Eng 122 (2019) 196–210]. Soil Dynamics and Earthquake Engineering. https://doi.org/10.1016/j.soildyn.2019.105845