What kind of sand is used for concrete: Analysis of hot topics on the Internet in the past 10 days
In the construction industry, the quality of concrete is directly related to the safety and durability of the project. As one of the important raw materials of concrete, the selection of sand is particularly critical. Recently, there has been a heated discussion on the entire Internet around "What sand to use for concrete?" This article will combine the hot content of the past 10 days to provide you with a detailed analysis of the selection criteria, type comparison and industry trends of sand for concrete.
1. Core standards for sand used in concrete
According to national standards and industry practices, sand for concrete needs to meet the following key indicators:
| indicator | Standard requirements | Detection method |
|---|---|---|
| Particle gradation | Comply with the requirements of Zone II in GB/T 14684-2022 | Sieving method |
| Mud content | ≤3.0% (concrete above C30) | flushing method |
| Mud content | ≤1.0% | Soaking method |
| Robustness | Quality loss ≤8% | sodium sulfate solution method |
2. Comparative analysis of mainstream sand types
In recent hot discussions, the following three types of sand have received the most attention:
| sand type | Advantages | Disadvantages | Applicable scenarios |
|---|---|---|---|
| natural river sand | The particles are round and well graded. | Resource depletion and high prices | high strength concrete |
| Machine-made sand | Stable source and low cost | Need to adjust the mix ratio | Ordinary concrete |
| Recycled aggregate sand | Environmental protection, policy support | Performance fluctuates greatly | non-load-bearing structure |
3. Industry hot trends
1.Breakthrough in machine-made sand technology: Reports from many places show that by improving the production process (such as vertical shaft impact crushing + winnowing powder removal), the particle shape and gradation of machine-made sand have reached the level of natural sand.
2.Recycled sand application accelerated: With the advancement of construction waste recycling policies, the utilization rate of recycled sand in Beijing, Shanghai and other places has increased by 35% year-on-year, but experts suggest that the chloride ion content needs to be strictly controlled.
3.Growing demand for specialty sand: Special scenarios such as island projects and nuclear power projects have promoted the research and development of special materials such as quartz sand (SiO₂≥90%) and high alumina sand, and the number of related patents has increased by 28% compared with the same period last year.
4. Practical suggestions for sand selection
For concrete with different strength levels, it is recommended to refer to the following combination schemes:
| concrete grade | Preferred solution | alternative | Things to note |
|---|---|---|---|
| C15-C25 | Machine-made sand (fineness modulus 2.6-3.0) | Mixed sand (manufactured sand + natural sand) | Control stone powder content ≤7% |
| C30-C50 | Natural medium sand (Zone II) | Fine machine-made sand | Admixture suitability testing is required |
| C60 and above | Graded special sand | quartz sand mixture | Strict testing of alkali activity |
5. Excerpts from expert opinions
Professor Zhao from the China Building Materials Research Institute emphasized in a recent interview: "In the next five years, machine-made sand will account for more than 70% of the market share, but a quality control system for the entire industry chain needs to be established, especially in terms of sand source stability and harmful substance detection."
The statistical period of the data in this article is from November 1 to November 10, 2023, and combines the popular discussion content of Baidu Index, WeChat Index and industry forums. The actual sand selection should be based on the specific needs of the project and follow the latest national standards.
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