Dry mix mortar is a granular or powdery material physically blended in fixed proportions from aggregates (such as quartz sand) processed through drying and screening, inorganic cementitious materials (such as cement), and additives (such as polymers). As a core material in construction, dry mix mortar is delivered to construction sites in bags or bulk, and it can be directly applied after mixing with water. Also known as dry mortar, dry mix mortar or dry-mixed powder, it represents a major trend in the future development of building materials, and its quality is closely related to the performance of manufactured sand produced by a sand making plant.
Requirements of Dry Mix Mortar for Manufactured Sand
Dry mix mortar has standardized requirements for consistency, apparent density, water retention rate, setting time, flexural / compressive strength, tensile bond strength, drying shrinkage rate, etc. These strict standards for dry mix mortar mean that manufactured sand, as its key raw material, must meet specific criteria in terms of particle roundness, fines content, fineness modulus and gradation—all of which are closely related to the performance of the sand making plant and crushing equipment used in production.
1. Fineness Modulus and Gradation Requirements
The production of high-quality manufactured sand for dry mix mortar relies on advanced sand making plant and matching crushing equipment. A professional sand making plant equipped with vertical shaft impact (VSI) sand makers (a core part of crushing equipment) can effectively reduce coarse sand larger than 2.36 mm and increase the proportion of fine sand suitable for dry mix mortar. Combined with precision screening technology in the sand making plant, the final sand product can fully meet the requirements of Zone II gradation in national standards, which is crucial for ensuring the performance of dry mix mortar.
Improved gradation of manufactured sand not only helps enhance the strength and fluidity of dry mix mortar, but also reduces the consumption of cementitious materials, thus improving dry mix mortar quality and lowering production costs for the dry mix mortar plant. The fineness modulus of manufactured sand for dry mix mortar is generally controlled within the range of 2.3–2.8, a standard that can be stably achieved by crushing equipment and screening equipments.
2. Particle Roundness Requirements
River sand yields excellent dry mix mortar due to its smooth surface and mostly spherical shape, which requires only a small amount of cementitious materials and mixing water during curing. River sand with rational particle size gradation is undoubtedly a high-quality aggregate for dry mix mortar, but its scarcity has promoted the wide use of manufactured sand produced by aggregate shaping and sand making plant.
However, natural river sand is formed over a long period through river scouring, erosion, transportation and other natural processes, resulting in highly rounded particles. Manufactured sand, produced by crushing stone with crushing equipment in an aggregate shaping and sand making plant, exhibits inferior roundness compared with river sand. Nevertheless, experiments and practical applications in dry mix mortar plant have proven that manufactured sand with flaky particle content not exceeding 12%—produced by crushing equipment and aggregate shaping and sand making plant—can replace river sand in dry mix mortar.
3. Stone Powder Content Requirements
Based on practical applications in dry mix mortar projects and dry mix mortar plant operations, when the methylene blue value (MB) ≤ 1.4, the stone powder content in plastering mortar should generally be controlled within 10%, while that in masonry mortar can be appropriately higher. This requirement can be effectively met by optimizing the process parameters of the sand making plant and crushing equipment, ensuring the stability of dry mix mortar quality.
Integrated Sand Making & Mortar Plant
Recommendeed Sand Making Equipment for Dry Mix Mortar
Based on the above requirements for manufactured sand used in dry mix mortar, an integrated aggregate shaping and sand making plant is highly recommended as the dedicated sand production system for dry mix mortar plant. This type of sand making plant is designed to meet the strict standards of dry mix mortar, integrating advanced crushing equipment and precision processing technology.
The aggregate shaping and sand making plant adopts a highly intensive, tower-type fully enclosed layout, integrating sand making, particle shape optimization, stone powder control, gradation adjustment, moisture content control and environmental protection treatment. Equipped with high-efficiency crushing equipment, not only significantly improves production efficiency for the dry mix mortar plant, but also upgrades key indicators of manufactured sand including particle shape, gradation and stone powder content, enabling the manufactured sand to achieve performance comparable to natural sand.
Crushing Equipment
Dry Mixed Mortar Plant
Sand Making Plant
Mortar Mixer
This aggregate shaping and sand making plant is widely applied in sand production for ready-mixed concrete plants, dry mix mortar plant and other related fields, providing stable and high-quality manufactured sand for dry mix mortar production and effectively supporting the efficient operation of dry mix mortar plant.