Research Specifications

This study aims to assess the influence of Polyacrylamide (PAM) on the mechanical and physical characteristics of two kinds of soft soils. A number of laboratory tests including consistency, standard proctor compaction, incremental loading consolidation, and desiccation tests were performed on the untreated and treated soils. The results indicated that addition of PAM caused a reduction in the soils plasticity indices. Although adding PAM led to a marginal increase in the maximum dry density of soils, it had a negligible impact on the optimum moisture content. Increasing PAM content reduced compressibility, initial void ratio, compression and swelling indices, coefficient of consolidation and permeability. Turning to the desiccation test, the cracking potential of soils decreased as PAM concentration increased. Moreover, to have a better interpretation of the stabilization mechanism as well as the microstructural changes induced by PAM, a number of spectroscopic and microscopic methods including FESEM and XRD analyses were performed on the soils. The results demonstrated that the PAM additive enables physical bonding between soil particles rather than chemical reactions. In other words, PAM does not change the soil in terms of the atomic structure of clay particles rather it alters the whole structure of clay mass by creating a strong connection network between soil particles via flocculating the aggregates.