Towards low-carbon deep soil mixing: a complementary review of supplementary cementitious and alkali-activated binders

Abstract

Deep soil mixing (DSM) is a proven in situ ground improvement technique conventionally employing cement/lime as hydraulic binders. Escalating concerns regarding greenhouse gas emissions and chemical durability of these materials have prompted the exploration of sustainable alternatives, notably supplementary cementitious materials (SCMs) and alkali-activated binders (AABs). This review consolidates recent progress in binder innovations, mix design approaches, and performance evaluation for sustainable DSM. Emphasis is placed on microstructural evolution, mechanical and durability characteristics, and field applicability. Publication trend analyses demonstrate the rapid growth of DSM-related research and the increasing focus on sustainable binders over the last 15 years (2011–2025). Reviewed studies indicate that SCM- and AAB-based systems can achieve engineering performance comparable to cement-treated soils under specific mix designs and curing conditions, although differences in soil type, water content, specimen preparation, and curing regime limit direct quantitative comparisons across studies. Binder treatment consistently enhances stiffness, reduces permeability, and improves resistance to consolidation, though the creep and dynamic response of AAB-stabilized soils remain underexplored. Field studies, though limited, indicate that optimized blends can meet or surpass design requirements, although variability and long-term performance remain concerns. Environmental aspects, including leachability, life-cycle assessment, and cost–performance trade-offs of alternative binders, are critically reviewed, and future research priorities are outlined to advance sustainable DSM practices.