Valorization of a Highly Organic Sediment: From Conventional Binders to a Geopolymer Approach

The Liquid Limit as a Factor in Assessing the Improvement of Stabilized Cement-Based Highwater Content Clayey Sediments

The purpose of this study was to assess the performance of high water content clayey sediments at different liquid limits as the clays are treated with cement-based solidifying materials. Three clay samples are obtained from different locations in the Kumamoto Reservoir. Two types of cement-based solidifying agents, namely, ordinary Portland cement and a cement-fly ash binder, were used. Using the initial water content of clay and the mixing amount of the solidifying agent as experimental variables, a cone penetration test was performed on the solidifying agent-stabilized clays to obtain the cone index (q_c). The results showed that when the water content to cementitious content ratio (w/A_W) was used as a parameter for evaluating the improvement of solidifying agent-stabilized clay, different forms of improvements were observed when different water and solidifying agent contents were used. This implied that the parameter w/A_W was not suitable for evaluating the improvement of such clay. A new parameter, K, representing the content of solidifying agent, was introduced to account for the water content. For all sampled clays, the correlation coefficients for the K-ln q_c relationship exceeded 0.9. Considering the effect of the liquid limit of the samples, the modified content of the solidifying agent (K_L) was introduced to evaluate the cone index of the stabilized soils. It was discovered that the proposed equation unified the assessment of the improvement of the three samples of Kumamoto clayey sediments owing to the new parameter, K_L.