Flowability and viscosity of freshly solidified dredged materials

The solidification method is an important way to dispose a large amount of dredged materials, and the flowability of freshly solidified dredged materials determines how to construct. The flowability and viscosity of two kinds of freshly solidified dredged materials are examined by the cone-cut and rotational viscometer tests. The initial water content influences the flowability and there is a critical water content, $w'$≈2.0${w_{\text{L}}}$. When w is above $w'$, the flowability increases quickly. The flowability decreases a lot after solidified. The more the cement amount, the less the flowability, and it mainly happens when a_c≤50 kg/m³. There is also a critical water content ${w'_{\text{s}}}$ that influences the flowability of freshly solidified dredged materials, and ${w'_{\text{s}}}$ is related to the cement content. When a_c =50 kg/m³, ${w'_{\text{s}}}$≈2.8${w_{\text{L}}}$, and the flowability of freshly solidifed dredged materials is about 2/3 of that of rawly dredged materials. The rotational viscometer tests show that when w > 12.0${w_{\text{L}}}$, the dredged materials are the Newtonian fluid; when 2.0${w_{\text{L}}}$≤w≤12${w_{\text{L}}}$, they belong to the Bingham fluid; and when w < 2.0${w_{\text{L}}}$, they are the pseudoplastic fluid with yield value. When w > 2.8${w_{\text{L}}}$, the freshly solidified dredged materials are defined as the Bingham fluid; and when w < 2.8${w_{\text{L}}}$, they are defined as the power-law fluid. The values of μ and ${\tau _0}$ of freshly solidified dredged materials are larger than those of rawly dredged materials, and both of them decrease with the increasing water contents. The cement content influences μ and ${\tau _0}$ mainly when a_c≤50 kg/m³. When the dredged materials and freshly solidified dredged materials are the Bingham fluid, the relationship between ${\tau _0}$ and flowability is determined according to two-dimensional shallow water equation.