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Papers  Submitted By
Michael Lazar and John Emery

"He  so improved the city that he justly boasted that he found it brick and left it  marble" - August
 
 

INNOVATIVE DEVELOPMENTS FOR PAVER SYSTEMS

Three forms of interlock should be present in a block paving system, namely:

· Rotational interlock which is achieved by the presence of edge restraints
· Vertical interlock which is provided by the presence of stable compacted sand between all joints
· Horizontal interlock, which is dependent upon a combination of laying pavers in a herringbone pattern and by the use of, shaped units.

Thus, interlock prevents pavers from 'creeping' i.e., movement of pavers horizontally when trafficked and resists rotational and vertical movement in relation to its neighbours.

The IPS was designed and developed by employing the latest technological methods in mould manufacture to create a paver that utilises a 'tongue and groove' locking device within each individual unit (see pciture below). This unique concept will provide a degree of 'interlock' exceeding that of all other block paving systems because of its mechanical locking system. Furthermore it will stabilise the paving surface to ensure that the danger of individual units being displaced is avoided and maintain the flexibility of a pavement constructed with pavers. For this reason the IPS is particularly suitable for aircraft pavements where displaced pavers have, in the past, resulted in near disastrous consequences.

IPS (Innovative Paver System) - View of alternate sides

A further problem that may be avoided with the IPS, is that of the so-called 'cluster effect'. This is a consequence of groups or 'clusters' of pavers being paletted in a final laying pattern to facilitate mechanical laying. Unfortunately, with few exceptions, it is rarely possible for one cluster to lock into adjacent clusters. The result of this is a tendency for a widening of joints to an unacceptable level as mechanical laying progresses.

Because of the mechanical interlocking effect of the IPS, it will overcome a further problem associated with traditional pavers, that of pavers becoming dislodged during stacking operations at the manufacturing plant.

The versatility of the interlocking paver system will enable units to be manufactured in a wide range of colours and with an integral reflective surface for special road marking situations. To reduce noise levels in trafficking areas units may be produced with 3mm chamfers.

The IPS can be manufactured using any existing automated paving block machines, although some hydraulic modifications and adjustments to machine controls will be necessary. The mould layout for the pavers will be approximately half that that of existing moulds, i.e. 20 rectangular pavers compared with 50 pavers of similar size. It is considered that this is a small price to pay when compared with the higher performance of this new paving concept.

SUMMARY OF  BENEFITS OF IPS
·  Improved interlock performance over conventional pavers 
· Flexibility of  paver surface maintained 
· Has the advantage of being a hand held unit  facilitating ease of laying where manual laying is necessary. 
· Prevents  dislodgement of units during stacking operations 
· Prevents dropping of  units during mechanical laying operations 
· Maintains uniform joint widths  during laying 
· Withstands removal by jet engine blast 
· Can be  manufactured in a wide range of colours and reflective surfaces 

TESTING
Testing of the tongue and groove units reported below was made by an independent accredited laboratory, namely, STATS Testing Ltd. of St Albans, UK. The purpose of the tests was; (a) to determine the quality of the tongue and groove units and confirm their compliance with British Standards requirements and ; (b) to compare their interlocking properties with those of conventional rectangular concrete pavers by performing compression and pullout tests. To confirm the suitability of the IPS system for aircraft pavements, jet efflux tests were made at Cranfield University in the UK using equipment specifically developed in their gas turbine laboratories for these tests. Test done on IPS:

1) Conformity Testing
2) Compression  Testing
3) Pullout  Testing
4) Jet Engine Exhaust Testing 

To print reports and details of test done.

Note:   Testimonials from APC's clients and Test Reports done by Cranfield University (UK) available upon request.