【Daily Discussion】Utilities - Civil Engineering - 20210607

1. Appearance: Black paste 2. Volatiles: 5±25% 3. Oxygen index: >30% (OI) 4. Adhesion strength: 1.5 kg/cm2 at 20°C 5. Density: 1600–1700 kg/m3 6. Heat resistance: When placed at an angle of 45 degrees at 95°C for 4 hours, or when the temperature rises to 120°C and it is still placed at a 45-degree angle for 1 hour, no flowing or bubbling occurs. 7. Frost resistance: No cracking or separation after being suspended at -40°C to +95°C for 2 hours each. 8. Operating temperature: -40~95°C. 9. Water absorption rate: After soaking at room temperature for 24 hours, the amount of water absorbed shall not exceed 1% of the weight of the test material. 10. Construction thickness: 6mm. 11. Drying time: 1 hour for finger contact, 60 hours for complete drying. 12. Construction volume: 12 kg per square meter (including losses)

Stone mastic asphalt (SMA) is an asphalt mixture in which asphalt mastic—composed of asphalt, fiber stabilizer, mineral powder, and a small amount of fine aggregate—fills the voids within a skeleton of continuously graded coarse aggregates. It is characterized by a high content of coarse aggregates, a high content of mineral powder, a large amount of asphalt used, and a low content of particles with intermediate particle sizes. In mixtures with a high content of coarse aggregate, the skeleton formed by direct face-to-face contact and interlock of particles directly bears the load; this skeleton is less sensitive to temperature. The mineral powder with a relatively high content and asphalt form a highly cohesive gelled substance—mastic—which improves the overall mechanical properties of the mixture. The effects of these two aspects ensure that the mixture has sufficient vertical and lateral restraint, so that under the action of vehicle loads, it does not undergo any permanent deformation, or only minimal permanent deformation.

1. Appearance: Black paste
2. Volatiles: 5±25%
3. Oxygen index: >30% (OI)
4. Adhesion: 1.5 kg/cm² at 20°C
5. Specific gravity: 1600–1700 kg/m³
6. Heat resistance: When placed at a 45-degree angle at 95°C for 4 hours, and then at 120°C for 1 hour, there is no dripping or bubbling. 7. Frost resistance: No cracking or separation after being suspended at -40°C to +95°C for 2 hours each. 8. Operating temperature: -40~95°C. 9. Water absorption rate: After soaking at room temperature for 24 hours, the amount of water absorbed shall not exceed 1% of the weight of the test material. 10. Application thickness: 6 mm. 11. Drying time: 1 hour for finger touch; 60 hours for complete drying. 12. Construction volume: 12 kg per square meter (including losses)

1. Appearance 2. Volatiles 3. Oxygen index 4. Adhesion 5. Specific gravity 6. Heat resistance 7. Freeze resistance 8. Operating temperature 9. Water absorption rate

The main technical performance indicators of asphalt mastic are heat resistance, flexibility, and adhesion.

1; Appearance: Black paste-like 2； Volatile matter: 5±25% 3 ； Oxygen index: >30% (OI) 4; Adhesion: 1.5 kg/cm² at 20°C 5 ； Specific gravity: 1600–1700 kg/m3. Heat resistance: At a temperature of 95°C, when placed at a 45-degree angle for 4 hours, the temperature rises to 120°C; even when kept at that angle for another hour, no flowing or bubbling occurs. 7; Frost resistance: No cracking or separation after being exposed to -40℃ and +95℃ for 2 hours each. 8 Operating temperature: -40~95°C. 9 ； Water absorption rate: After soaking at room temperature for 24 hours, the water absorbed should not exceed 1% of the weight of the sample. 10; Construction thickness: 6mm. 12; Drying time: 30 minutes for finger contact, 60 hours for complete drying.

SMA is an asphalt mixture composed of asphalt, a stabilizer, sand, along with a small amount of fine aggregate; it fills the gaps between the coarse aggregate particles in a graded pattern. It is characterized by a high content of coarse aggregates, a high content of mineral powder, a large amount of asphalt used, and a low content of particles with intermediate particle sizes. In mixtures with a high content of coarse aggregate, the skeleton formed by direct face-to-face contact and interlock of particles directly bears the load; this skeleton is less sensitive to temperature. The mineral powder with a relatively high content and asphalt form a highly cohesive gelled substance—mastic—which improves the overall mechanical properties of the mixture. The effects of these two aspects ensure that the mixture has sufficient vertical and lateral restraint, so that under the action of vehicle loads, it does not undergo any permanent deformation, or only minimal permanent deformation.

1. Appearance: Black paste 2. Volatiles: 5±25% 3. Oxygen index: >30% (OI) 4. Adhesion strength: 1.5 kg/cm2 at 20°C 5. Density: 1600–1700 kg/m3 6. Heat resistance: When placed at an angle of 45 degrees at 95°C for 4 hours, or when the temperature rises to 120°C and it is still placed at a 45-degree angle for 1 hour, no flowing or bubbling occurs. 7. Frost resistance: No cracking or separation after being suspended at -40°C to +95°C for 2 hours each. 8. Operating temperature: -40~95°C. 9. Water absorption rate: After soaking at room temperature for 24 hours, the amount of water absorbed shall not exceed 1% of the weight of the test material. 10. Construction thickness: 6mm. 11. Drying time: 1 hour for finger contact, 60 hours for complete drying. 12. Construction volume: 12 kg per square meter (including losses)

The main technical performance indicators of asphalt mastic are heat resistance, flexibility, and adhesion.