National Standards for Construction Sand and Specifications for Manufactured Sand
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National Standards for Construction Sand and Specifications for Manufactured Sand
Manufactured sand, after soil removal, is produced through mechanical crushing and screening processes. Its particle size is less than 4.75 mm, and it originates from rocks, mine tailings, or industrial waste particles. However, it's important to clarify that soft and weathered particles are not included; these are typically referred to as artificial sand.
Specifications of Manufactured Sand:
Manufactured sand is classified according to its fineness modulus (Mx), specifically into four types: coarse, medium, fine, and extra-fine. Different specifications of manufactured sand have different average particle sizes. For example, coarse sand has a fineness modulus between 3.7 and 3.1, with an average particle size greater than 0.5 mm; while extra-fine sand has a fineness modulus between 1.5 and 0.7, with an average particle size less than 0.25 mm. Generally speaking, the higher the fineness modulus, the coarser the particle size of the manufactured sand, and vice versa.
Grades and Applications of Manufactured Sand:
(1) Grade Classification: Manufactured sand is typically classified into three grades: I, II, and III, based on its technical requirements.
(2) Application Areas:
Grade I Sand: Suitable for producing concrete with a strength grade higher than C60.
Grade II Sand: Suitable for concrete with a strength grade between C30 and C60, as well as concrete with special requirements such as frost resistance, impermeability, etc.
Grade III Sand: Mainly used for producing concrete with a strength grade lower than C30 and for construction mortar.
Detailed Requirements for Manufactured Sand:
The particle size range of manufactured sand is strictly limited to 4.75-0.15mm. Specific proportional limits are also set for the content of stone powder smaller than 0.075mm. Its particle size is meticulously divided into: 4.75, 2.36, 1.18, 0.60, 0.30, and 0.15mm. A continuous particle size distribution is required, and the proportion of each particle size in the total should be appropriate. In addition, the particle shape of manufactured sand should be as cubic as possible, and the content of needle-like and flaky particles should be controlled within a certain range.
