What kind of sand is used for concrete? ——Analysis of hot topics across the Internet and scientific sand selection guide
Recently, "what kind of sand to use for concrete" has become a hot topic in the construction industry and decoration field. Especially in the context of tightening environmental protection policies and the shortage of natural sand resources, how to scientifically select sand has triggered widespread discussion. This article will provide you with structured analysis based on the hotspot data of the entire network in the past 10 days.
1. Statistics of hot topics across the entire network (last 10 days)
| keywords | peak search volume | Main discussion platform | Hot trends |
|---|---|---|---|
| Machine-made sand | 8,200 times/day | Zhihu/Baidu | ↑35% |
| sea sand concrete | 5,600 times/day | Douyin/Kuaishou | →Smooth |
| Desert Sand Application | 3,400 times/day | Academic forum | ↑18% |
| recycled aggregate | 2,800 times/day | Industry website | ↑42% |
2. Comparison of core indicators of sand used in concrete
| sand type | Particle size range (mm) | Mud content (%) | Chloride ion content | Applicable strength level |
|---|---|---|---|---|
| natural river sand | 0.15-4.75 | ≤3 | extremely low | C15-C60 |
| Machine-made sand | 0.075-4.75 | ≤5 | none | C30-C80 |
| Sea sand (after processing) | 0.15-5.0 | ≤1 | ≤0.06% | C20-C40 |
| Recycled fine aggregate | 0.08-4.75 | ≤7 | indefinite | C15-C30 |
3. Current mainstream sand selection solutions
1.High strength concrete (C50 and above): Priority is given to Zone II graded machine-made sand, which requires the stone powder content to be controlled between 7% and 10%. The latest research shows that appropriate stone powder can improve compactness.
2.Ordinary civil buildings: The solution of using a mixture of 50% river sand + 50% machine-made sand is the most popular, which not only ensures workability but also reduces costs. 63% of users in the recent Douyin #Self-Build House topic adopted this solution.
3.coastal area engineering: When desalinated sea sand must be used, it must be ensured that the chloride ion content is ≤0.02% (more stringent than the national standard). A case in which a project in Fujian was reworked due to failure to meet the standard has recently become a hot topic.
4. Analysis of the Focus of Disputes
1.Problems with edges and corners of machine-made sand: Zhihu hot post pointed out that the sphericity of machine-made sand produced by vertical shaft impact crusher can reach more than 0.7, which significantly improves the fluidity.
2.Desert sand feasibility: The latest test from Xinjiang University shows that after modification, desert sand below 0.6mm can replace 30% of conventional sand (data source: June issue of "Journal of Building Materials").
3.Improvement of environmental standards: The "Construction Sand" GB/T 14684-2022, which will be implemented on July 1, has new radioactive testing requirements. The relevant discussion has been viewed more than 500,000 times in the popular science video on Station B.
5. Expert advice
Experts from the Chinese Academy of Building Sciences emphasized in a recent live broadcast:"When selecting sand, you need to follow the principle of three things—see whether the grading curve is continuous, look at the harmful substance detection report, and look at the actual trial mixing effect.". Consumers are particularly reminded that the error rate of the popular "sand identification method" on Douyin is 40%, and they should rely on professional testing.
Note: The data statistics period of this article is from June 15th to 25th, 2023, covering the monitoring results of Baidu Index, Xinbang, Qingbo and other platforms. With technological advancement and policy adjustments, relevant standards may change, and it is recommended that the latest specifications prevail.
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