Research Information System
Geomechanics and Geoengineering, 2025 (ESCI, Scopus)
The growing need for sustainable construction has prompted the use of environmentally friendly alternatives to traditional cement in soil stabilisation. This study investigates the effects of sewage sludge (SS) and sewage sludge ash (SSA), activation temperature, curing time, and compaction on the strength and durability of cement-stabilised clay. SS and SSA were incorporated at 0–10% with cement dosages of 5–10%, densities of 1.5 and 1.7 g/cm3, and curing durations of 7, 28, and 60 days. Durability, evaluated using a normalised durability index, indicated that 3–5% fresh SS achieved the most stable performance. SSA activated at 600°C further improved durability under optimal curing and compaction. However, SSA at 300°C showed limited reactivity, and at 1100°C became largely inert. Strength assessments revealed that curing time, density, and cement content are key to unconfined compressive strength, with the best results observed at 1.7 g/cm3, 10% cement, and 60 days curing. XRD analysis confirmed enhanced amorphous phase formation and portlandite consumption in mixes activated at 600°C, supporting pozzolanic activity. A sustainability-focused mix design recommends 3–5% fresh SS, 7% cement, high compaction, and 60-day curing to balance strength, durability, and reduced embodied energy.