Stabilised compressed earth bricks made with coastal solonchak

This paper presents a study on the production of stabilised compressed earth brick (SCEB) using coastal solonchak. The solonchak collected along the coastal area of Tianjin, China was characterised. With activation pretreatment, the pozzolanic activity of the saline soil was significantly enhanced and the SCEB with high strength and water resistance has been produced. Three chemical additives, i.e. sodium silicate, hydrofluoric acid and phosphoric acid were used in the activation pretreatment. The results indicated all of these have the effects to enhance the pozzolanic activity of the saline soil with lime and Portland cement and phosphoric acid gave the best results in terms of the activity index test. SCEB was then produced with activation pretreated saline soil, lime, Portland cement and sand with pressure moulding and standard curing. The mixes with 50% activated saline soil obtained 28 day compressive strength 28-55% higher and water resistance 44-66% higher than the reference mix using untreated saline soil, with more effective at low PC content. The study also revealed that the produced SCEB could be degraded back to soil for plantation after demolish and long term weathering. This study thus provided prospective environmentally friendly masonry units for sustainable construction.