The quality of slurry used in diaphragm wall construction is critical to the overall performance and durability of the final structure. A key concern is the formation of a thick slurry cake at the interface between the slurry and the in-situ soil. This thick cake can detach during concreting operations, leading to contamination of the freshly placed concrete. The incorporation of slurry cake into the concrete mix weakens the structural integrity and can create pathways for water ingress and chemical attack, compromising the long-term durability of the diaphragm wall.
Furthermore, an excessively thick slurry cake reduces the effective concrete cover over the reinforcement. This diminishes the protection afforded to the steel bars, making them more susceptible to corrosion. Corrosion of the reinforcement weakens the bond between the concrete and steel, further accelerating the deterioration of the diaphragm wall.
Therefore, maintaining optimal slurry quality is essential to ensure the formation of a thin and stable filter cake. This involves carefully controlling the slurry’s properties, such as density, viscosity, and filtration rate. By minimizing the thickness of the slurry cake, engineers can enhance the bond between the concrete and soil, maximize the concrete cover over the reinforcement, and ultimately create a more durable and resilient diaphragm wall that can withstand the test of time.