Sustainable infrastructure is one of the sustainable development goals (SDGs) introduced by the United Nation. By utilizing waste materials as recycled and reused materials in construction, it offers great benefits to people, the economy and the environment for sustainable infrastructure in geotechnical project development. The low strength of marine subgrade pavement soil can be improved by chemical stabilization from abundant natural waste near the coastal area. The use of seashells such as cockle shells in powder formed can be considered a potential sustainable natural waste additive in replacing lime and cement for stabilized marine soil. Yet, its potential performance in improving geotechnical properties has not extensively been investigated. Thus, the unconfined compressive strength of stabilized marine soil with cockle shell powder (CSP) was assessed experimentally. The treated soil specimens were mixed with 2.5%, 5%, 7.5% and 10% of CSP (by dry weight of the soil sample) and prepared in the cylindrical dimension of 38 mm in diameter and 76 mm in height prior to unconfined compression test based on the optimum moisture content (OMC) obtained from the compaction test. All experiments were carried out in accordance with British Standard. The results show that the CSP can improve the strength of stabilized soil. The highest strength is 636.785 kPa for soil mixed with 10% of CSP which 157% increase compared with untreated soil. Therefore, the results of the study have shown that the addition of CSP to marine soil has improved significantly the unconfined compressive strength in soil stabilization, especially for pavement such as highways, airport runways and parking areas.
