I. Materials
1. Asphalt: A blackish-brown solid/semi-solid viscous substance obtained through crude oil distillation, solvent extraction, or coal processing, or naturally occurring. It is the core binder of asphalt mixtures.
2. Coarse aggregate: Aggregates such as crushed stone, crushed gravel, screened gravel, and slag with a particle size greater than 2.36mm in asphalt mixtures are the core components constituting the aggregate skeleton structure.
3. Fine aggregate: This refers to natural sand, manufactured sand, and stone chips with a particle size less than 2.36mm in asphalt mixtures. Its core function is to fill the gaps between coarse aggregates and improve the density of the mixture.
4. Filler: Mineral powder with a particle size of less than 0.075mm, common types include cement, lime, fly ash, and finely ground limestone powder.
5. Modified asphalt: Asphalt binder with properties optimized by adding modifiers such as rubber, resin, polymers (e.g., SBS, SBR), and finely ground rubber powder, or by undergoing slight oxidation processing.
6. Emulsified asphalt: A uniformly dispersed system (asphalt emulsion) made by high-speed shear emulsification of petroleum asphalt (or coal tar pitch) and water under the action of emulsifiers and stabilizers. It is classified into spray type (for tack coat and primer coat) and mixing type (for ambient temperature mixtures) according to application scenarios.
7. Cationic emulsified asphalt: Positively charged emulsified asphalt prepared with cationic emulsifiers has strong adhesion to acidic aggregates (such as granite), fast demulsification speed, and is suitable for tack coat and prime coat construction.
8. Anionic emulsified asphalt: negatively charged emulsified asphalt prepared with anionic emulsifiers has good compatibility with alkaline aggregates (such as limestone), high mixing stability, and is often used for mixing asphalt mixtures at room temperature.
II. Mixed Materials
1. Asphalt mixture: The general term for mixtures formed by mixing mineral aggregates (coarse aggregates, fine aggregates, and fillers) with asphalt binders in a designed ratio. It is the core road construction material for asphalt pavements.
2.
Asphalt Concrete Mixture: Asphalt concrete, also known as asphalt concrete, is a mixture of coarse aggregate, fine aggregate, and filler aggregates arranged in a continuous gradation, mixed with asphalt to produce a mixture that meets technical standards (represented as LH when graded using a round-hole sieve).
3. Dense-graded Asphalt Concrete: A mixture with continuous aggregate gradation and dense interlocking particles, resulting in a residual void ratio of <10% after compaction. Type I dense-graded asphalt concrete (void ratio 3%–6%, 2%–6% for pedestrian roads) is suitable for main road surfaces; Type II semi-dense-graded asphalt concrete (void ratio 4%–10%) is suitable for secondary roads.
4. Semi-open graded asphalt mixture: also known as asphalt macadam mixture (represented by LS when graded by round hole sieve), it is made by mixing coarse aggregate, fine aggregate and a small amount of filler (or no filler) with asphalt. The residual void ratio after compaction is >10%. It is suitable for road base or subbase.
5. Open-graded asphalt mixture: The aggregate gradation is mainly coarse aggregate with a low content of fine aggregate. The particles are dispersed and the porosity after compaction is >15%. It has drainage and noise reduction functions and is often used for the surface layer of drainage pavement.
6. Gap-graded Asphalt Mixture: The aggregate gradation is missing one or more particle size grades (such as missing 4.75~9.5mm particles), forming a skeleton-void or skeleton-dense structure, such as OGFC (open-graded drainage asphalt wearing course).
7. Emulsified asphalt aggregate: This is an ambient temperature mixture made by mixing emulsified asphalt and aggregates at room temperature. It has a compaction residual void ratio of >10%, is energy-saving and environmentally friendly, and is suitable for low-grade highways or maintenance projects.
8. Extra coarse asphalt macadam mixture: maximum aggregate size ≥37.5mm (45mm for round hole sieve), suitable for road subbase.
9. Coarse-grained asphalt mixture: The maximum aggregate size is 26.5mm or 31.5mm (30-40mm for round hole sieve), suitable for the lower layer of the road surface.
10. Medium-grained asphalt mixture: The maximum aggregate size is 16mm or 19mm (20mm or 25mm for round hole sieve). It is suitable for the intermediate layer of the road surface and is the core structural layer material of high-grade highways.
11. Fine-grained asphalt mixture: The maximum aggregate size is 9.5mm or 13.2mm (10mm or 15mm for round hole sieve), suitable for the surface layer of road.
12. Sandy Asphalt Mixture: Maximum aggregate size ≤ 4.75mm (5mm for round hole sieve), also known as asphalt stone chips or asphalt sand, suitable for sidewalks, bicycle lanes or road seals.
III. Construction-related
1. Hot-mix asphalt pavement: Asphalt and aggregates are mixed at 150-180℃ and paved at 120-150℃. This is the mainstream construction technology for high-grade highways.
2. Asphalt mixture pavement at ambient temperature: pavement made by mixing emulsified asphalt or diluted asphalt with aggregates at ambient temperature (5-35℃), which is convenient to construct and energy-saving and environmentally friendly.
3. Prime coat: To enhance the adhesion between the asphalt surface layer and the non-asphalt base layer (such as cement-stabilized crushed stone base layer), a thin, penetrating layer of emulsified asphalt, coal tar pitch, or liquid asphalt is poured onto the base layer surface, with a penetration depth ≥5mm.
4. Tack Coat: A thin layer of asphalt material applied to enhance the bond between asphalt layers and between asphalt layers and cement concrete pavement or bridge deck. The application rate is controlled between 0.3 and 0.6 kg/m².
5. Sealing Coat: A thin layer of asphalt mixture laid to seal the voids on the road surface and prevent moisture intrusion. The layer laid on the surface of the surface course is called the upper sealing coat (anti-skid, anti-aging), and the layer laid below the surface course is called the lower sealing coat (waterproof, bonding).
6. Slurry seal: The seal is formed by mixing stone chips, fillers (cement, fly ash, etc.), emulsified asphalt, admixtures and water in a certain proportion to form a fluid dynamic mixture, which is then evenly spread on the road surface.
7. Crushed stone seal: This is a seal layer formed by first spreading asphalt binder, then evenly spreading crushed stone and compacting it. It is suitable for preventive maintenance of road surfaces.
8. Liquid petroleum asphalt: A product made by diluting petroleum asphalt with solvents such as gasoline, kerosene, and diesel. It is also known as light asphalt or diluted asphalt and is suitable for tack coat and primer coat construction.
9. Paving temperature: The temperature during asphalt mixture paving. The paving temperature of hot-mix asphalt mixture is ≥120℃.
10. Compaction temperature: The temperature during asphalt mixture compaction. Initial compaction temperature ≥ 110℃, final compaction temperature ≥ 70℃.
11. Curing period: The time from the completion of asphalt pavement construction to the opening of traffic. The curing period for hot-mix pavement is ≥4 hours, and for normal temperature pavement it is ≥24 hours. The specific time needs to be adjusted according to the temperature and the type of mixture.
12. Recycling Construction: The process of using a milling machine to recycle old asphalt pavement material (RAP material), which is then screened, heated, and mixed with new aggregates and new asphalt to form recycled mixture for repaving the road surface.
13. Milling: The operation of breaking and cutting old asphalt pavement with a milling machine, recycling old materials and repairing the pavement base.
IV. Equipment
1. Asphalt Mixture Mixing Equipment: Also known as asphalt mixing plant/mixing equipment, it is the core equipment for preparing road surface mixtures by heating, metering, and mixing asphalt, aggregates, powders, and additives according to the designed proportions.
2. Forced Intermittent Asphalt Mixing Equipment: Employing a “batch batching-forced mixing” mode, each batch independently completes aggregate screening, heating, metering, and mixing, enabling precise control of the mix proportions (deviation ≤ ±1%) and quality. It is the preferred equipment for high-grade highway construction.
3. Continuous Asphalt Mixing Equipment: Production equipment for continuous heating, batching, and mixing of aggregates, with high production efficiency (up to 400t/h), suitable for large-scale road engineering.
4. Recycled Asphalt Mixture Mixing Equipment: This equipment integrates the functions of recycling, screening, heating, and mixing of recycled materials. It can add 0-50% RAP material.
5. Mobile asphalt mixing plant: The equipment modules can be quickly disassembled, transported, and assembled, making it suitable for temporary projects or remote construction sites.
6. Fixed Asphalt Mixing Plant: A large-scale mixing equipment fixedly installed on site, with strong production capacity (100-600t/h), suitable for long-term, large-scale projects.
7. Indoor Asphalt Mixture Production Line: The mixing equipment, material yard, and loading and unloading processes are integrated into a closed workshop to achieve full-process indoor operation, effectively control dust and noise pollution, and meet environmental protection requirements.
8. Aggregate heating system: The core component of the asphalt mixing plant, which uses a burner to heat the aggregate to 160-190℃.
9. Asphalt Storage Tanks: Insulated containers used for storing asphalt.
10. Powder Supply System: Composed of powder silos, screw conveyors, and weighing scales, it is responsible for the storage, transportation, and accurate metering of fillers.
11. Dust Removal Equipment: To handle the dust generated during the mixing process.
12. Asphalt Sprayer Truck: A vehicle specially designed for uniformly spraying tack coat, primer, and liquid asphalt.
13. Paver: A specialized piece of equipment that spreads asphalt mixture evenly on the road surface. The paving thickness (0-300mm) and width (2-12m) can be adjusted.
14. Road Roller: Equipment used to compact the paved mixture, achieving a specified density (≥96%) and strength through rolling.
15. Milling machine: Specialized equipment for milling and crushing old asphalt pavement.
Note: The content of this article is for reference only.
