Slurry leakage in the production of concrete utility poles refers to the phenomenon in which cement slurry in the concrete is thrown out at high speed along the joint seams of the steel mold during centrifugal molding. Sampling inspection data show that seam leakage accounts for a high proportion of appearance defect items, and its harm goes far beyond appearance. Slurry loss weakens the compactness of the concrete and forms interconnected capillary channels, making it easier for chloride ions, moisture and carbon dioxide to penetrate, accelerating steel reinforcement corrosion and shortening the service life of the pole.

The root causes can be summarized as "failure to seal" and "failure to mix properly." "Failure to seal" means the sealing of the steel mold seam fails. After long-term use, old molds deform and the seam gap increases; after demolding, hardened cement mortar remains in the tongue-and-groove and is not cleaned thoroughly, resulting in poor mold closing; when bolts are tightened, they are not tightened symmetrically and evenly, causing uneven stress on the seam and local gaps. During centrifugal molding, the high-speed rotation of the steel mold produces runout, further aggravating the opening of the seam. "Failure to mix properly" refers to the concrete mixture itself. An excessive water-cement ratio, a high sand ratio, and too low a slump cause segregation, all of which make the slurry more likely to escape through the gap under centrifugal force. Preventing slurry leakage requires systematic measures in three aspects: mold, mix proportion and operation.

The mold is the first line of defense against slurry leakage. Before closing the mold, cement residue at the tongue-and-groove must be completely removed to keep the parting surface clean. Placing a sealing rope in the tongue-and-groove is an effective method; paper rope, hemp rope or special sealing strips are all acceptable. The key is to place it evenly and flatly to prevent the rope from embedding into the concrete and forming defects. Structural improvements such as T-shaped sealing gaskets and dovetail grooves matched with trapezoidal rubber strips can prevent the seal from jumping out or shifting during mold closing, significantly improving sealing reliability. Old molds that have been used for a long time should be regularly straightened and repaired to ensure that the seam gap meets requirements.

Optimizing the mix proportion reduces the tendency to leak slurry from the source. The water-cement ratio should be strictly controlled according to the design strength grade, and the proportion of fine aggregate should be appropriately increased to enhance the cohesiveness of the slurry and avoid segregation aggravating slurry leakage. Mixing must be uniform and sufficient to prevent local slurry from being too thin. Operating standards must not be ignored. When closing the mold, bolts must be tightened symmetrically and evenly, and missing tightening or one-sided over-tightening must be eliminated. During feeding, prevent stones from being trapped in the mold opening, so as not to prop the seam open. The centrifuge should be regularly checked for roller diameter and installation status to reduce the runout of the steel mold during centrifugation and suppress dynamic opening of the gap from the motion source. Slurry leakage prevention cannot be achieved by a single measure; it is the result of the coordination of mold precision, material mix proportion and operating discipline. Only by integrating sealing maintenance, mix proportion control and centrifugal operation standards into the entire production process of every pole can tight seams and no slurry escape be achieved, ensuring the long-term durability of the pole.