1. Materials conform to GS1992⁽¹⁾ requirement
   All Marshall mixes stipulated in the specification, including 10 and 20 mm wearing course material, 10 mm friction course material, 28 and 37.5 mm base course material.
2. 20 mm SMA (Stone Mastic Asphalt)⁽²⁾
   An impermeable wearing course material. Resistant to mechanical and temperature deformation, cracking, and particularly rutting. Also resists weathering actions such as ageing and low-temperature cracking. The textured surface increases the skid-resistant properties. Durability is excellent even under slow moving heavy traffic.
3. 10 mm polymer modified friction course material
   Noise reducing and more durable to deformation than normal design friction course material. Skid-resistant and improved safety during rain due to the open-textured design and water permeation properties.
4. 10 mm wearing course material
   A refined surface due to smaller nominal size aggregate than 20 mm wearing course. Also used as a regulating course material because of the small nominal size of aggregate.

1. Mastic asphalt
   A wearing course material often using on suspension bridges. Able to reduce weight on the bridge deck because of its relatively thin application. Highly durable to adverse weather conditions. Resistant to cracking and deformation due to large temperature variation, movement and vibration of the underlying structure due to traffic or wind. An impermeable and voidless pavement which also serves a water-proofing function.
2. 37.5 mm coarse asphaltic TLA material
   A rut- and crack-resistant material incorporating Trinidad Lake Asphalt. Designed by Anderson Asphalt for extremely high volume traffic conditions.
3. 20 mm wearing course TLA material
   A rut- and crack-resistant wearing course material incorporating Trinidad Lake Asphalt. Designed by AAL for extremely high volume traffic conditions.
4. Rubber asphalt To the client’s specific requirement. Shock-absorbing to provide comfortable riding.

1. Materials conform to BS4987⁽³⁾ or GS1992⁽¹⁾ requirements
   Materials such as the 37.5 mm road base material, 20 mm DBM and 10 mm DBM.
2. 6 mm fine asphalt
   Conforms to BS4987, used as the uppermost surface material when refined surface regularity is required.

1. Bituminous primer
   Provides good contact between the lower structure and upper bituminous layers. Sometimes serves as a water impervious layer to protect the upper bituminous structure from water action.
2. Emulsified bituminous tack coat
   Provides good contact between adjacent bituminous layers.
3. Cut-back bitumen On client’s specific request.
4. Granular sub-base material
   An unbound structural layer which distributes loads, and provides a surface of uniform strength for the construction of the upper road base and surfacing layers. Conforms to GS1992⁽¹⁾.

⁽¹⁾General Specification for Civil Engineering Works, 1992, Hong Kong Government.
⁽²⁾Conforms to GS1992 and Draft Specification for 20 mm Sized Stone Mastic Asphalt Material, Rev. A.
⁽³⁾Specification for Coated Macadam for Roads and Other Pavement Areas.