In cast-in-place pile construction, when pouring concrete underwater, a certain amount of overpour is required to ensure the strength of the pile head. The excess concrete at the top of the pile must then be chiseled away; this process is known as pile cap finishing. As the final and critical step in pile foundation work, how is pile head finishing performed?
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1.Initial Chiseling of Pile Heads
Pile chiseling shall be performed using the manual layered oblique splitting method or hydraulic pile breaker with High work efficiency. The elevation of the pile head must conform to the red-painted elevation control points as measured by the project department. The elevations marked with red paint shall account for the thickness of the base course, waterproofing, and waterproofing protection layer to ensure that the pile head elevation does not fall below the design elevation or the embedment depth of the base slab after chiseling is complete.
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2.Pouring the Subbase
Control the elevation; first install corner guards at the construction joints and pile head areas, then proceed with large-area pouring. Take care to avoid contaminating the pile heads during the pouring process.
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3. Secondary Chiseling
After the subbase has been poured, perform secondary chiseling to the height of the reserved piles.
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4.Pile Head Finishing
Clear debris from the subgrade and straighten the rebar at the pile head.
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5. Waterproofing of Pile Heads
Exposed surfaces on the top and sides of pile heads shall be coated with a cement-based penetrating crystalline waterproofing coating, extending 150 mm onto the subgrade of the structural slab; a polymer-modified cementitious waterproofing mortar transition layer shall be applied within a 300 mm radius around the pile head.
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6.Installation of the Floor Waterproofing Layer
Lay the waterproofing membrane on the floor slab, extending it to the side walls of the pile cap. The joints between the membrane and the side walls of the pile cap should be filled with sealant.
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7. Waterproof Sealing of Pile Head Reinforcement
Water-swelling waterstop strips or waterstop sealant shall be applied to the base of the load-bearing reinforcement at the pile head. The waterstop strip must be tightly adhered to the base surface of the construction joint. The sealing material shall be compacted, continuous, and fully filled, and shall adhere firmly.
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8. Pouring the Protective Layer
Set elevation points at 2-meter intervals when pouring the waterproof protective layer to ensure that concrete work does not contaminate the pile heads. Any areas contaminated by concrete residue should be rinsed immediately.
Nancy Fan . June 16, 2026
Post time: Jun-16-2026