🏗️ 1. Core characteristics of bauxite and road application basis
Physical performance enhancement
High hardness and wear resistance: The Mohs hardness of calcined bauxite clinker is above 8, and the volume density is increased to 2.8-3 g/cm³, which is significantly higher than traditional aggregates such as basalt7.
Porous structure: The internal micropores of calcined bauxite are well developed, which can enhance the asphalt adsorption capacity and increase the oil-stone ratio of the mixture (need to increase by about 0.3%-0.5%), thereby improving the adhesion between asphalt and aggregate1.
Chemical stability
After high-temperature calcination, bauxite loses crystal water and volatiles, and its acid and alkali resistance and weather resistance are enhanced. It is suitable for the needs of airport pavements exposed to corrosive environments such as fuel and deicing agents for a long time37.
🛣️ 2. Specific application methods in airport high-speed wear-resistant roads
As high-performance aggregate
Ultra-thin wear layer (UTFC): Calcined bauxite (such as 88#, 75# grades) replaces part of traditional aggregates (basalt, limestone) to pave a wear layer with a thickness of ≤2.5 cm. Its high hardness can resist the repeated shear force of aircraft takeoff and landing, and reduce rutting deformation15.
Mixture design optimization: Due to the high water absorption rate of bauxite, it is necessary to improve the mix design (such as coarse aggregate void filling method) and add polymer modified asphalt to improve adhesion5.
Key materials for anti-skid surface
Friction performance durability: Three rounds of accelerated wear tests showed that after 50,000 wears, the dynamic friction factor (DFT) of 88# calcined bauxite mixture still remained above 0.50 (basalt was only 0.40), and the difference in high-speed and low-speed friction attenuation was less than 5%, ensuring safety in rainy and foggy weather1.
Surface texture optimization: bauxite particles have sharp edges and corners, which can increase the pavement macro texture depth (MPD), improve drainage and skid resistance, and reduce the risk of water drift18.
Composite modification application
Epoxy resin-bauxite anti-skid layer: bauxite aggregate is embedded in the epoxy resin matrix to form a highly wear-resistant composite material layer, which is used in high-wear areas of the runway (such as landing areas) to extend the service life by more than 30%58.
Cement-based reinforcement: Adding bauxite fine powder to high-grade concrete can improve the pavement compressive strength (up to 60 MPa or more) and freeze-thaw resistance, which is suitable for high-cold airports38.
📊 3. Technical advantages and performance comparison
Performance indicators Calcined bauxite mixture Traditional basalt mixture Improvement effect
High temperature stability Dynamic stability ≥6000 times/mm About 5000 times/mm Improved by 20%1
Long-term skid resistance After 50,000 wear times DFT＞0.50 DFT≈0.40 Attenuation rate reduced by 25%1
Low temperature crack resistance Bending strain ≥2800με About 2500με Improved by 12%1
Water stability Freeze-thaw splitting strength ratio ≥85% About 80% Improved by 5%1
🧪 4. Actual engineering application and verification
Case 1: SMA-5 ultra-thin wear layer
The domestic airport test section was paved with 88# calcined bauxite. After 2 years of operation, the rutting depth was only 3.2 mm (6.5 mm in the basalt section), and the skid resistance value BPN was maintained above 55, which is much higher than the safety threshold (BPN≥45)15.
Case 2: High-cold Airport Reconstruction
The runway of a northeastern airport uses a bauxite-epoxy resin composite layer. After 50 freeze-thaw cycles at -30°C, the surface has no peeling, and the friction coefficient attenuation rate is less than 10%, which is significantly better than ordinary concrete8.
⚙️ V. Application Challenges and Optimization Directions
Cost and Process Adaptability
The cost of calcined bauxite is about 30% higher than that of basalt, and the full-cycle cost needs to be balanced by improving the durability of the mixture6.
High porosity requires matching high-viscosity modified asphalt (such as SBS, rubber asphalt), and strict construction temperature control requirements1.
Resource Sustainability
Promote low-grade bauxite homogenization technology, use tailings to prepare recycled aggregates, and reduce dependence on raw materials (for example, in the test in Jiaozuo, Henan, the tailings addition reached 40% and still met the strength requirements)56.
💎 Summary
Bauxite (especially calcined clinker) has become an ideal material for high-speed wear-resistant roads at airports due to its high hardness, porous adsorption and stable skid resistance. By optimizing the mixture design, the durability and safety of the pavement can be significantly improved. In the future, further efforts should be made to tackle cost control and green preparation technology to promote its large-scale application in aviation infrastructure.
