PEDESTRIAN, VEHICULAR, OR SPORTS PLAYING SURFACE

STRUCTURES

This invention relates to pedestrian, vehicular, or sports playing surface structures and in particular to a method of forming such structures. Another aspect of the invention concerns a method of making paving slabs or the

5 like.

According to a first aspect of the invention, a method of forming a pedestrian, vehicular, or sports playing surface structure, comprises providing within the structure a layer of an open fibrous material filled with

10 a hardened self setting composition.

The layer may be formed by laying a mat of the open fibrous material on a suitable base layer within the structure, for example soil or sand, fil.ling the material with the self setting composition in substantially liquid 15 or slurry form, and allowing the composition to harden. The filling is suitably carried out by working the com¬ position into the material with a brush. Alternatively, the layer is formed using preformed slabs of the filled and hardened material, suitably factory produced. 20 The layer may be uppermost within the structure, or may have other materials laid on to it, for example arti¬ ficial turf.

Preferably the self setting composition is cement based, for example Portland cement based. The cement

25 based composition may contain sand, rubber or plastics crumbs or particles, or a mixture of such materials. As an alternative, the self setting composition may be bitu-

„ men or a synthetic resin, with a sand or other filler if desired. f 30 The fibrous material is preferably a needle punched synthetic fibre mat, for example of polyester, acrylic, or polypropylene fibres, with more preferably a resin binder.

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It has been found that surface structures formed in accordance with this aspect of the invention are very durable, and are much less susceptible to damage, whether accidental or deliberate, than any conventional surfaces, while being simple to construct.

Another aspect of the invention provides a method of making a paving slab or the like, comprising introducing a self setting composition into a sheet of an open fib¬ rous material so as substantially to fill the material with the composition, and allowing the composition to set. The self setting composition and the fibrous mater¬ ial may be as hereinbefore described with reference to the first aspect of the invention.

It has been found that paving slabs so produced are of substantially greater strength than conventional pav¬ ing slabs and can therefore be made thinner and therefore lighter. This gives substantial savings both in the cost of transporting and of laying the slabs.

The slabs are readily coloured and textured during manufacture in the same manner as conventional concrete slabs and may even be moulded to form non-planar slabs, for example for edging purposes.

In tests on different cement/sand mixtures as fill¬ ers for a 4 mm thick needle-punched synthetic fibre wadd- ing, the variation in strength with proportion of cement in the mixture from 25% to 100% is analogous to that which would be obtained without reinforcement, with 100% cement having a very low tensile strength, but high com¬ pressive strength, for example. However, the tensile strength is substantially increased by the presence of the wadding, such that a filled 12.5 mm to 18 mm non-res¬ in bonded wadding has a similar strength to 50 mm thick concrete of the same mix, and where the wadding is resin- bonded, a 4 mm thick filled layer is equivalent in strength to a filled 12.5 mm non-resin bonded wadding

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layer. Thus, a paving slab can be made substantially thinner by the use of the wadding, without loss of strength, the weight of the slab being only a quarter, or a smaller fraction, of the weight of a conventional pav- ing slab.