What are the quality requirements for the selection of coarse aggregate and sand aggregate for asphalt concrete bases?
Lifting Columns Suzhou Herstar Medical Technology Co., Ltd. , https://www.hosunherstar.com
September 14 07:36:04, 2025
I. Asphalt Concrete Base: Quality Requirements for Coarse Aggregates
For the asphalt concrete base course, the quality requirements of the coarse aggregates used in the selected asphalt mix should comply with the standards specified for urban road projects, as outlined in Table 1.4.6.
The following are the key quality requirements for coarse aggregates used in asphalt concrete bases:
| Index | Asphalt Concrete Base |
|-------|------------------------|
| Stone Crush Value (not greater than %) | 30 |
| Los Angeles Abrasion Loss (not more than %) | 40 |
| Apparent Density (not less than t/m³) | 2.45 |
| Water Absorption (not greater than %) | 2.0 |
| Adhesion to Asphalt (not less than) | Level 3 |
| Soundness (not more than %) | 12 |
| Flaky and Elongated Particles (not greater than %) | 20 |
| Washing Method Particle Content (not greater than %) | 1 |
| Soft Stone Content (not greater than %) | 5 |
| Polishing Value (not less than BPN) | 42 |
| Impact Value (not greater than %) | 28 |
| Broken Crushing Area (for upper, middle, and lower layers) | 40 |
Note: The soundness test can be conducted as needed. The polishing value, impact value, and other parameters should be referenced according to the "Asphalt Pavement Construction and Acceptance Specifications."
II. Quality Requirements for Sand Aggregate in Asphalt Concrete Base
For the asphalt concrete base course, the quality requirements for sand used in the selected asphalt mix should also follow the specifications of urban road projects, as shown in Table 1.4.7.
The following table outlines the grading requirements for natural sand used in asphalt concrete:
| Square Hole Sieve (mm) | Round Hole Sieve (mm) | Coarse Sand (%) | Medium Sand (%) | Fine Sand (%) |
|-------------------------|------------------------|------------------|------------------|----------------|
| 9.5 | 10.0 | 100 | 100 | 100 |
| 4.75 | 5.0 | 90–100 | 90–100 | 90–100 |
| 2.36 | 2.5 | 65–95 | 75–100 | 85–100 |
| 1.18 | 1.2 | 35–65 | 50–90 | 75–100 |
| 0.6 | - | 15–29 | 30–59 | 60–84 |
| 0.3 | - | 5–20 | 8–30 | 15–45 |
| 0.15 | - | 0–10 | 0–10 | 0–10 |
| 0.075 | - | 0–5 | 0–5 | 0–5 |
| Fineness Modulus (Mx) | - | 3.7–3.1 | 3.0–2.3 | 2.2–1.6 |
This table is based on the "Asphalt Pavement Construction and Acceptance Specifications." It is important to ensure that the sand used meets these grading criteria to maintain the stability and durability of the asphalt concrete base. Proper selection of sand not only improves workability but also enhances the overall performance of the pavement structure. Always verify the material properties before use and conduct necessary tests to confirm compliance with the required standards.