What is the required fineness modulus for sand used in concrete, and which type of sand-making machine is preferable

Manufactured sand and manufactured sand concrete are progressively replacing natural sand as vital raw materials in contemporary construction operations. This transition ensures overall construction quality and efficiency while laying a solid foundation for achieving anticipated project objectives. For concrete sand, the fineness modulus is typically required to be between 3.7 and 1.6, generally indicating a predominance of medium-grade sand. Small quantities of coarse and fine sand may be added, but the ratio must be maintained at 4:1. Beyond fineness, concrete sand must also exhibit appropriate gradation. Gradation optimises void filling: using sand of uniform fineness leaves larger voids, whereas blending two or three particle sizes minimises voids. This approach not only conserves cement during concrete production but also enhances the density and strength of concrete and mortar.

Here is a breakdown of the specific particle sizes for coarse, medium, and fine sand:

Coarse sand: Fineness modulus 3.7–3.1, average particle size ≥0.5mm.

Medium sand: Fineness modulus 3.0–2.3, average particle size 0.5–0.35mm.

Fine sand: Fineness modulus 2.2–1.6, average particle size 0.35–0.25mm.

The production process for concrete sand mirrors standard manufactured sand production, involving crushing, screening, sand-making, and washing. For final product specifications, the output particle size can be controlled by adjusting the sand-making machine's discharge settings to meet concrete material requirements.

Which sand-making machine delivers the required output particle size?

We recommend the OCP Heavy Industry PLS Series Vertical Impact Crusher (Sand-Making Machine). Operating at high rotational speeds exceeding 80 metres per second, it is ideal for re-crushing and shaping coarse sand particles in the aggregate processing industry. This optimises the gradation of finished sand, enabling a finer modulus of fineness. It excels in fine crushing and shaping operations for diverse rock types, particularly demonstrating superior performance over other equipment when processing medium-hard, ultra-hard, or abrasive materials such as sandstone, granite, basalt, silicon carbide, emery, bauxite, and magnesia.

1. Deep-cavity rotor design creates a larger crushing chamber for increased throughput. This enhances sand-making efficiency while ensuring thorough impact between stones against the crushing wall and against each other within the chamber. The result is greater fragmentation with minimal grinding, improving sand yield, reducing powder content, and delivering superior sand-making results.

2. Hydraulic cover release mechanism and oil-thinning lubrication system. The hydraulic cover release allows direct access for maintenance during daily operations. The oil-thinning lubrication system effectively safeguards normal operation with minimal leakage, ensuring environmentally sound production throughout. Low noise levels prevent disturbance to the surrounding environment.

3. Internal air recirculation within the vortex chamber minimises dust leakage. The self-contained airflow within the vortex chamber prevents dust overflow, ensuring environmentally sound production throughout. Low noise levels further avoid disturbing the surrounding environment.

4. Wear-resistant components with extended service life

All wear-prone parts are concentrated in the discharge head, which is constructed from high-grade steel. The modular design ensures superior abrasion resistance and prolonged operational longevity.

For cost-effective, high-quality sand-making machinery backed by reliable after-sales support, OCP Heavy Industry is your assured choice. Click for online consultation to obtain complimentary product specifications and quotations!