A practical framework for using long-chain PHPA polymer as a bentonite alternative in foundation piling. Covers mixing, contamination, maintenance, concrete displacement, and how to stabilise a bored pile under fluid.
The Challenge
Engineers and contractors need confidence that pile load-carrying capacity is not adversely affected by slurry choice during construction, and that the approved slurry is not detrimental to structural capacity or pile life.
The Approach
A systematic approach using Swell Stop (Dry) PHPA polymer with soda ash water treatment, PAC polymer support in porous formations, and real-time viscosity, pH and sand content monitoring. Slurry level maintained two to three metres above the water table to maintain hydrostatic overbalance. Concrete displacement managed via tremie with piston pump to preserve polymer chain integrity.
The Outcome
Long-chain PHPA polymer maintains shaft stability with lower disposal costs, no filter cake skin friction risk, and a cleaner pile base for concrete placement. 'The cost between different providers is often tiny; the difference in technical advice and support available at design, through project execution, and during the review should be the primary factor.'