Compressive Strength Evaluation of Shell- and Lime-Modified Earth Using Recycled Cockle Shell Additive and Particle Packing

This article investigates the compressive strength of shell- and lime-modified earth, using sandy limestone as the case study material. Reframed as a feasibility pilot investigation, recycled cockle shells are utilized as a sustainable mineral filler. This methodology implements a dual-strategy framework. First, a granular gradient, guided by the Fuller-Thompson target gradient model, refines particle packing and contributes to physical matrix density. Second, fine recycled cockle shell powder is proposed to function as a physical micro-filler to refine particle grading and affect compaction behavior. Experimental results yield a peak unconfined compressive strength (UCS) of 2.98 ± 0.21 MPa at the conclusion of the 90-day primary curing interval, demonstrating feasibility for moderate-strength earthen applications with a comparable estimated embodied-carbon profile.