**Abstract:** With the rapid development of highway construction, both domestic and imported concrete pumping equipment have become widely used by construction companies. However, during the concrete pouring process, improper usage often leads to blockage failures in the equipment. These issues not only delay project progress but also directly impact the quality of the work. This paper discusses the causes of pipeline blockages, the symptoms of different types of blockages, and effective solutions for each situation. It also outlines preventive measures to reduce the likelihood of such problems occurring. **1. Causes of Blockage** Under normal conditions, the central part of the pipe carries a columnar flow of concrete, with a layer of mortar on the surface acting as a lubricant that reduces friction against the pipe walls. The coarse aggregates within the mix move relatively smoothly without much sliding. However, when some coarse aggregates become stuck, the following particles slow down, leading to an accumulation of material in the pipe. As the mortar supporting these aggregates is squeezed out, smaller particles fill the gaps, increasing the density of the mixture. This results in a radial expansion of the pipe’s cross-section, damaging the lubrication layer and increasing resistance. Eventually, the movement stops, causing a complete blockage. **2. Identification and Removal of Blockages** **2.1 Blockage at the Inlet** Symptoms: The pump operates normally, with no unusual noise or vibration. However, large aggregates or clumped material may be stuck at the feed inlet. Solution: Reverse the pump to break up the blockage, return the concrete to the hopper, remix it, and then pump it forward again. If this fails, manual cleaning is required. **2.2 Blockage at the Outlet (Distribution Valve)** Symptoms: The pumping system suddenly stops, accompanied by abnormal noises and strong vibrations, while the pipeline shows no corresponding movement. Solution: Add 15–30 liters of grout into the hopper and repeatedly pump in both directions to clear the blockage. If ineffective, manual removal is necessary—disassemble the connected pipes and clean the valve debris. **2.3 Blockage at the S-Pipe Valve** Symptoms: The blockage develops gradually, usually due to failure to flush the S-pipe with high-pressure water after pumping. Over time, residual concrete thickens and hardens, causing a blockage. Solution: After pumping, always use high-pressure water to clean the pump and S-pipe. If this doesn’t work, use brazing to remove the hardened material until the pipe is clear. **2.4 Blockage in the Conveying Pipe** Symptoms: Pumping pressure increases, but the hopper level remains unchanged. No material comes out of the pipe, and both the pump and pipe vibrate strongly. Solution: Immediately use the reverse-pump method to push the concrete back into the hopper for remixing. A wooden hammer can be used to tap along the pipe; a dull sound indicates a blockage. If this doesn’t work, disassemble the pipe and clean it using high-pressure air, water, or a heavy hammer before reassembling and continuing. **3. Preventive Measures to Avoid Pumping Concrete Clogging** (1) When installing and designing the pipeline, avoid sharp bends like 90° and S-shaped curves to reduce resistance and prevent blockages. (2) Ensure continuous pumping operations and avoid long interruptions. If unavoidable, run the pump every 5–10 minutes to prevent material from setting. (3) Follow the specified mix design for pumped concrete and strictly control the slump. (4) Use 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 small amount of mortar to prevent blockage. (6) During hot weather, cover the pipeline with wet burlap to slow down the concrete’s setting and reduce the risk of blockage during pumping. By implementing these practices, construction teams can significantly reduce the occurrence of blockages, improve efficiency, and ensure the quality of concrete placement.

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