Mechanically Stabilised Semi-Rigid Pavements

A method of constructing a semi-rigid pavement, the method comprising:

• a) providing a geosynthetic above a subgrade;
• b) providing aggregate and binder over the geosynthetic such that the geosynthetic is at least partially embedded in the aggregate;
• c) setting the binder to form a support layer comprising chemically-stabilised aggregate;
• and
• d) providing an upper course comprising an upper course aggregate and a hydrocarbon binder above the support layer.

A method of constructing a semi-rigid pavement with an improved lifespan, the method comprising:

• a) at least partially embedding a geosynthetic within an aggregate and a binder;
• and
• b) setting the binder to form a support layer comprising chemically-stabilised aggregate,
• wherein the support layer is incorporated into the semi-rigid pavement during construction.

A method of constructing a semi-rigid pavement with a reduced thickness, the method comprising:

• a) at least partially embedding a geosynthetic within an aggregate and a binder;
• and
• b) setting the binder to form a support layer comprising chemically-stabilised aggregate,
• wherein the support layer is incorporated into the semi-rigid pavement during construction.

A method of operating a semi-rigid pavement, the semi-rigid pavement comprising a subgrade, a support layer of chemically-stabilised aggregate above the subgrade, wherein a geosynthetic is at least partially embedded in the layer of chemically-stabilised aggregate, and an upper course above the chemically-stabilised aggregate, wherein the semi-rigid pavement is capable of exhibiting:

• a first operating mode wherein the support layer is substantially monolithic, the support layer being chemically and mechanically stabilised such that load applied to the upper course is transferred to the subgrade;
• and
• a second operating mode wherein the support layer is at least partially cracked, the support layer being mechanically stabilised such that load applied to the upper course is transferred to the subgrade;
• the method comprising permitting traffic to pass over the semi-rigid pavement in at least one of the first and second operating modes.

A method of designing a semi-rigid pavement for a location, the semi-rigid pavement comprising:

• an upper course comprising upper course aggregate and a hydrocarbon binder;
• a support layer comprising chemically-stabilised aggregate, the support layer located below the upper course;
• and
• a subgrade, the subgrade located below the support layer;
• wherein a geosynthetic is at least partially embedded in the chemically-stabilised aggregate that comprises the support layer:
• the method comprising:
• a) determining a target lifespan for the semi-rigid pavement;
• b) determining the properties of the subgrade present at the location;
• c) selecting the support layer of chemically-stabilised aggregate above the subgrade, wherein a geosynthetic is at least partially embedded in the layer of chemically-stabilised aggregate;
• d) selecting the upper course;
• e) predicting a predicted lifespan of the semi-rigid pavement comprising the subgrade, the selected support layer, and the selected upper course;
• f) comparing the predicted lifespan with the target lifespan;
• and
• g) repeating steps c) to f) if the predicted lifespan is less than the target lifespan.

A method of designing a semi-rigid pavement for a location, the method comprising:

• a) determining a target lifespan for the semi-rigid pavement;
• b) determining the properties of a subgrade present at the location;
• c) selecting a pre-designed semi-rigid pavement for the location, the pre-designed semi-rigid pavement comprising the subgrade, the selected support layer, and the selected upper course;
• d) predicting a predicted lifespan of the pre-designed semi-rigid pavement;
• e) comparing the predicted lifespan with the target lifespan;
• f) if the predicted lifespan is less than the target lifespan, at least partially embedding a geosynthetic in the support layer and repeating steps d) and e).

A method of maintaining a semi-rigid pavement, the semi-rigid pavement comprising:

• an upper course comprising upper course aggregate and a hydrocarbon binder;
• a support layer comprising chemically-stabilised aggregate, the support layer located below the upper course;
• and
• a subgrade, the subgrade located below the support layer;
• wherein a geosynthetic is at least partially embedded in the chemically-stabilised aggregate that comprises the support layer;
• the method comprising:
• a) determining acceptable values for one or more properties of the semi-rigid pavement;
• b) waiting a survey period;
• c) surveying the semi-rigid pavement and determining if the one or more properties of the semi-rigid pavement satisfy the acceptable values;
• d) undertaking maintenance if the one or more properties of the semi-rigid pavement do not satisfy the acceptable values;
• and
• e) repeating steps a) to d).