**Abstract:** With the rapid advancement of highway construction, both domestic and imported concrete pumping equipment have become widely adopted by construction companies. However, during the process of concrete pouring, improper usage often leads to equipment blockage, which not only delays the project schedule but also compromises the quality of the work. This paper discusses the causes of blockages in pumping systems, identifies common blockage locations, and provides practical solutions for their removal. Additionally, it outlines preventive measures to minimize the occurrence of such issues. **1. Causes of Blockage** Under normal conditions, the central portion of the pipeline carries a columnar flow of concrete, with a layer of mortar on the surface acting as a lubricant against the pipe walls. The coarse aggregates within the mixture remain relatively stationary, while the surrounding mortar provides support. When certain aggregates become obstructed, the following particles slow down, leading to a buildup of coarse materials inside the pipe. As the supporting mortar is squeezed out, smaller aggregates fill the gaps, increasing the density of the mixture. This results in an uneven distribution across the pipe’s cross-section, damaging the lubrication layer and increasing resistance. Eventually, movement stops, causing a complete blockage. **2. Identification and Removal of Blockages** **2.1 Blockage at the Inlet** Symptoms: The pumping system and hydraulic functions are normal, with no unusual noises or vibrations. However, large aggregates or caked material may be stuck in the feed inlet. Solution: Reverse the pump to break up the clump, return the concrete to the hopper, remix it, and then pump forward again. If this fails, manual cleaning is required. **2.2 Blockage at the Outlet (Distribution Valve)** Symptoms: Sudden interruption of the pumping action, accompanied by abnormal noise and strong vibrations, but no corresponding movement in the pipeline. Solution: Add 15–30 liters of grout into the hopper and repeatedly pump in both directions to dislodge the blockage. If ineffective, manual removal of the valve debris is necessary. **2.3 Blockage of the S-Pipe Valve** Symptoms: Gradual blockage occurs due to failure to clean the S-pipe after pumping. Residual concrete hardens over time, leading to accumulation and eventual blockage. Solution: Immediately flush the pump and S-pipe with high-pressure water after use. If still blocked, use brazing or other methods to remove the hardened material until the pipe is clear. **2.4 Blockage in the Concrete Conveying Pipe** Symptoms: Increasing pressure without a drop in the hopper level, no material exiting the pipe, and strong vibrations along the pipeline. Identification: Blockages commonly occur at elbows or conical sections. Tap the pipe with a small hammer; a dull sound indicates a blockage, while a crisp sound suggests normal flow. Solution: Use the reverse-pumping method to push the concrete back into the hopper for remixing. Combine with tapping using a wooden hammer. If this fails, manually remove the affected section, clean it with high-pressure air, water, or a heavy hammer, and reconnect the pipeline. **3. Preventive Measures to Avoid Pumping Blockage** (1) During pipeline installation, avoid sharp bends like 90° and S-shaped curves to reduce resistance and prevent blockage. (2) Ensure continuous pumping operations and avoid long intervals. If unavoidable, run the pump every 5–10 minutes to maintain flow. (3) Strictly follow the design mix proportions for pumping concrete and control the slump appropriately. (4) Select aggregates that meet size requirements, generally not exceeding 1/4 of the pipe diameter. (5) Before pumping, lubricate the pipe with clean water and first send a thin layer of mortar before introducing the concrete. (6) In hot weather, cover the pipeline with wet burlap to slow down the setting of the concrete and reduce the risk of blockage during pumping. By implementing these strategies, construction teams can significantly reduce the likelihood of blockage, ensuring smoother operations and higher-quality concrete placement.

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