Cement pipes are very common in our daily lives. When it comes to selecting raw materials for their production, here are some tips from a Zhengzhou cement pipe manufacturer:
The choice of sand: Generally, medium sand is used due to its good workability in concrete, good impermeability, but lower strength and a tendency to collapse during pipe manufacturing. The sand used in cement pipe-making machines is coarser, leading to poor workability in concrete but good impermeability, with higher strength and less tendency to collapse during pipe manufacturing. The selection of the sand ratio is also crucial; a higher sand ratio improves workability and moldability in concrete, along with better impermeability, but concrete is more prone to collapse during pipe manufacturing. Conversely, a lower sand ratio results in poor workability and moldability in concrete, along with worse impermeability, but the concrete is less likely to collapse during pipe manufacturing.
2. Cement Selection: It is advisable to use ordinary portland cement due to its smaller water-cement ratio in dry concrete mix, resulting in minimal volume change upon drying. The initial setting time of the cement for pipe-making machines is relatively short, with higher early strength, which is beneficial for the stability and density of concrete, preventing wall collapse, and enhancing steam curing.
3. Stone Selection: For small-diameter suspended roller pipes, pebbles or crushed pebbles should be used to reduce the frictional resistance on the stone surface, making it easier for concrete to compact and form. For large-diameter suspended roller pipes, machine-crushed stone is recommended, taking advantage of the rough surface of the stones for easier interlocking, thereby reducing the likelihood of concrete collapse.
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