What is first-grade fly ash
Fly ash is a common industrial by-product in the construction and building materials industries, especially in concrete production. According to its physical and chemical properties, fly ash can be divided into different grades, among whichFirst grade fly ashIt is favored for its excellent performance. This article will introduce in detail the definition, characteristics, applications and comparison with other grades of fly ash.
1. Definition of first-grade fly ash
First-grade fly ash refers to high-quality fly ash that meets national standards (such as GB/T 1596-2017) after strict screening and processing. Its main features are high fineness, good activity and low carbon content, which can significantly improve the strength and durability of concrete.
| indicator | Level 1 fly ash requirements |
|---|---|
| Fineness (45μm sieve allowance) | ≤12% |
| Loss on ignition | ≤5% |
| water demand ratio | ≤95% |
| SO3 content | ≤3% |
2. Characteristics of first-grade fly ash
1.High activity: First-grade fly ash contains a large amount of active SiO2 and Al2O3, which can react secondary with cement hydration products to improve the later strength of concrete.
2.filling effect: Due to its fine particles, it can fill the gaps in the concrete and improve the density and impermeability.
3.Environmental protection: As industrial waste reused, the use of first-grade fly ash reduces cement consumption and reduces carbon emissions.
3. Application of first-grade fly ash
First-grade fly ash is widely used in the following fields:
| Application areas | Specific use |
|---|---|
| concrete | High-strength concrete, mass concrete, pumped concrete |
| Building materials | Cement admixtures, blocks, bricks |
| road works | Roadbed filling, pavement materials |
| Environmentally friendly | Wastewater treatment, soil improvement |
4. Comparison between first-grade fly ash and other grades of fly ash
According to national standards, fly ash is divided into primary, secondary and tertiary levels. Here's how they compare:
| indicator | First grade fly ash | Secondary fly ash | Level three fly ash |
|---|---|---|---|
| Fineness (45μm sieve allowance) | ≤12% | ≤25% | ≤45% |
| Loss on ignition | ≤5% | ≤8% | ≤15% |
| water demand ratio | ≤95% | ≤105% | ≤115% |
5. Market status of first-grade fly ash
In recent years, with the tightening of environmental protection policies and the increasing demand for high-performance materials in the construction industry, the market demand for primary fly ash has continued to rise. Here is some market data:
| Year | Price of first-grade fly ash (yuan/ton) | Demand (10,000 tons) |
|---|---|---|
| 2021 | 180-220 | 1200 |
| 2022 | 200-240 | 1500 |
| 2023 | 220-260 | 1800 |
6. Future development trends of first-grade fly ash
1.Technology upgrade: With the advancement of sorting and processing technology, the output and quality of first-level fly ash will be further improved.
2.policy support: The state encourages the resource utilization of industrial solid waste, and the application scope of first-class fly ash will be wider.
3.market demand: The demand for green buildings and infrastructure construction will continue to drive the market growth of primary fly ash.
In summary, first-grade fly ash, as a high-performance building material, has broad application prospects in the fields of construction and environmental protection. Understanding its characteristics and applications will help you better realize its value.
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