Effectiveness of Fly Ash and Polyacrylamide as a Sand-Fixing Agent for Wind Erosion Control

Abstract

Searching for an effective and economical sand stabilization measure has an important significance in wind erosion control. Wind tunnel experiments were conducted to evaluate the sand-fixing effect of fly ash (FA) at three different application rates (10, 20, and 30 % (w/w) soil). The additional effect of polyacrylamide (PAM) was also studied under two different application rates (0.05 and 0.1 % (w/w) soil) on the basis of the optimum FA usage. The results indicated that the utilization of FA increased the threshold wind speed of the treated soil significantly, which was further increased by the addition of PAM. The soil treated with 20 % FA could most effectively withstand the pure wind with a wind speed of 8 m s−1 for 10 min, while only the slightest wind erosion occurred after exposure to the sand-carrying wind with a wind speed of 8 m s−1 for 10 min. However, moderate wind erosion occurred after exposure to both the pure wind and the sand-carrying wind with a wind speed of 14 m s−1 for 10 min, respectively, and there was a decline in the wind erosion rate with the increase of FA application rate. The soil treated with 20 % FA and 0.05 or 0.1 % PAM could effectively withstand the pure wind with a wind speed of 14 m s−1 for 30 min, while only the slightest wind erosion occurred after exposure to the sand-carrying wind with a wind speed of 14 m s−1 for 30 min. The combination of a 20 % FA and 0.05 % PAM application rate is recommended to give effective and economical wind erosion protection.