Effect of soil conditioner on Atterberg limits of clays and its mechanism

Abstract:

To select ideal type and content of soil conditioner in clay formation, the Atterberg limits of clay were measured. The applicability of soil conditioners was determined and the effects of dispersant on different clays were compared by analyzing the influence of soil conditioners on the clays. The Zeta potentials with different dispersant contents and repulsive energy among particles were also measured to analyze action mechanism of the dispersants. The results show that it is difficult to achieve ideal effect only by using anionic-cationic foam individually. The flocculant increases the liquid limit and plasticity index of the bentonite, so it also contributes to the increase of the shear strength. In the contrary, the dispersant decreases the liquid limit and plasticity index of the clay, thus it can decrease the shear strength, which makes the dispersant more suitable for clay conditioning. Compared with kaolin, the mixture (the mass ratio of bentonite to kaolin is 1:1) and bentonite require much time and dispersant due to high content of bonding water in bentonite. The effect of dispersant keeps unchanged after the injection ratio of dispersant reaching a certain value. With the increase in dispersant content, the Zeta potential decreases (i.e., negative charge increased) and tends to a lower constant in bentonite, kaolin and their mixture. The mean barrier potential V_max/R of clayey particles get higher with more dispersant, thus it is more difficult for the clays to be agglomerated and easier to disperse.