Interlock For Porphyry Pavers

  

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 Porphyry Pavers

Flexible porphyry pavement, using unbound aggregates, needs to be laid correctly and achieving interlock is one of the crucial final steps. In flexible installations, natural stone pavement construction uses granular materials as bedding and joint infill. The pavement is stabilized through a combination of friction, element interlock and bedding support.

 The elements are stabilized by mechanical interlock and friction.

All stone elements should have textured faces, such as the snap cut Copper Mountain Porphyry.

The support structure must be made compatible with the surface layer, i.e. a flexible surface layer requires a flexible support structure

Adequate compaction of support materials (roadbase and sub-base) is critical to ensure a uniform support for the surface layer.

Edge details are critically important. A rigid support must be provided at all edges to a flexible pavement construction. The spreading of loads through the action of interlock and friction produces horizontal forces that require resistance at the edges of the work.

The moisture content of the bedding aggregate during compaction should be at, or close to, optimum.

A flexible stone surfacing requires joints to be topped-up in its early life with additional aggregate as the system ‘shakes-down’ and ‘stiffens up’ under traffic loading.

Porphyry cubes should be laid in curved patterns described as an overlapping arc pattern in vehicular areas.

The drawing below illustrates three types of directions that the forces of traffic can exert, and properly achieved interlock can prevent.                                                    

The porphyry paver elements, laid on a suitable support layer, are bedded into a layer of fine rock aggregate, and the same material can be used to fill the joints between the elements. The effect is to ‘lock’ the elements together by friction and laying pattern. For dimensional porphyry material, off set joints and right angles are best, with porphyry cubes the overlapping arc is recommended as laying patterns that best achieve interlock. The bedding layer allows a smooth profile to be achieved with elements of varying depth, and it provides the initial stabilization of the elements. Blinding the surface with fine aggregate and

compacting the surface packs the fine aggregate within the joints and bedding, generating friction between the materials. A vibratory compactor or “wacker plate” as the British refer to it, is necessary to correct compaction and achieving interlock.

Porphyry's composition determines its high compression strength, resistance to stains, slip resistance, and high freeze/thaw ratings.  The stone is the most popular paver in Europe, and is favored for its flexibility in design, beauty, durability and low maintenance requirements. The stone is by far one of the most durable pavers in the world.  These materials are available from Milestone Imports. – www.milestoneimports.com