Compressive Strength of Acrylic Polymer-Stabilized Kaolinite Clay Modified with Different Additives

[Image: see text] Although numerous studies have shown the successful use of acrylic-based polymers as one of the chemical substances to improve soil mechanical behavior, their basic ingredients in commercial products are not revealed due to the manufacturers’ confidential policy. Among them, additives including pH control agents, thickeners, antifoams, and wetting agents are widely well-known owing to their enhancement effects on different properties of polymers. However, the effect of additives on the soil–polymer mixture is not completely investigated. Therefore, in this study, some of the frequently used additives in acrylic polymers were selected to investigate the effects of each one on the compressive strength of clayey soil. These additives include xanthan gum, Tylose, and carboxymethyl cellulose (CMC) as thickeners, sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and Kenon 10 as wetting agents, an ether-based antifoaming agent, and ammonia solution as a pH control agent. A combination of each additive (between 0 and 5% by weight) and polymethyl methacrylate-co-butyl acrylate (with 5% by weight) was added to kaolinite soil to measure the variation of unconfined compressive strength (UCS) and the stress–strain behavior of the soil–polymer–additive mixture. The results indicated that thickeners significantly affected the unconfined compressive strength up to 248% and increased the ductility of the stabilized samples. Acidic pH of the emulsion led to higher unconfined compressive strength of the stabilized soil up to 2.33 times that with alkaline. It is also demonstrated that the use of a higher amount of anionic wetting agent resulted in higher failure strain and lower unconfined compressive strength.