What is the fineness modulus
In the fields of architecture, civil engineering and materials science,Fine DimensionIt is a key parameter to describe the particle coarseness and fineness of aggregates such as sand and gravel. It directly affects the strength, durability and construction performance of concrete. This article will explain the definition, calculation methods and practical applications of fineness modulus through structured data and combined with popular discussions across the entire network for the past 10 days.
1. Definition of fineness modulus
Fineness Modulus (FM) is a numerical value determined by screening tests, reflecting the average particle size distribution of aggregate particles. The larger the value, the thicker the aggregate; otherwise, the thinner it is. It is usually used to evaluate the suitability of sand and is an important basis for designing concrete mix ratios.
| Fine Module Range | Aggregate type | Applicable scenarios |
|---|---|---|
| 3.1-3.7 | coarse sand | High-strength concrete |
| 2.3-3.0 | Middle sand | Ordinary concrete |
| 1.6-2.2 | Fine sand | Mortar or decoration project |
2. Hot topics across the network: Controversy in the application of fineness modulus
In the past 10 days, the discussion on "whether the fineness modulus is outdated" has become a hot topic in the engineering field. Some experts believe that modern concrete technology has optimized its performance through other parameters (such as particle grading), and the reference value of fineness modulus has decreased; while traditional schools emphasize its irreplaceability in construction convenience and cost control.
| Viewpoint | Support rate (sampling across the network) | Main basis |
|---|---|---|
| The fineness modulus is still necessary | 62% | |
| The fineness modulus can be eliminated | 38% | More accurate grading curve |
3. Calculation method of fineness modulus
Standard calculations require the screening of aggregates through standard screens (such as 4.75mm, 2.36mm, etc.), record the percentage of each screen remaining, and calculate according to the following formula:
| Mesh hole size (mm) | Sample sieve allowance (%) | Cumulative screening residue (%) |
|---|---|---|
| 4.75 | 8 | 8 |
| 2.36 | 18 | 26 |
| 1.18 | twenty four | 50 |
| 0.6 | 20 | 70 |
| 0.3 | 16 | 86 |
| 0.15 | 14 | 100 |
In the above table, fineness modulus = (8+26+50+70+86+100)/100 =3.4(It is coarse sand).
4. Frequently Asked Questions in Construction
Recently, a case of concrete cracking at a construction site caused heated discussions due to the failure of the fineness modulus. Here are the FAQs and solutions:
| question | reason | Solutions |
|---|---|---|
| Inadequate intensity | FM too high (aggregate too thick) | Add fine sand or adjust cement ratio |
| Water rupture phenomenon | FM too low (aggregate too thin) | Reduce water consumption or add water reducing agent |
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