COMCON S01 are straight polymer concrete road kerbstones of inverted channel (U) cross section. COMCON S01RX are curved polymer concrete road kerbstone of identical cross section, but of different radius of curvature. All types are intended to border the elevated or marginal parts of the carriageway.

Advantages

• high compressive strength

• high tensile strength and tensile strength in flexure

• high impact strength

• high abrasion resistance

• permanent resistance to freezing and thawing

• permanent resistance to de-icing salts and other de-icing agents

• permanent resistance to acid rains

• permanent resistance to petroleum products

• any fast colour

• absolute impermeability and negligible absorptivity

• easy installation

• long service life

• extreme resistance to climatic factors incl. UV radiaton

Application

• permanent bordering of carriageway and its separation from footways or the median

• permanent colour marking of bans and commands in the meaning of traffic regulations

The road kerbstones have principal dimensions of 200 x 245 x 1000 mm, wall thickness in the weakest (built-in) point 50 mm, a positive vertical face inclination of 3.75% (the kerbstone base is 200 mm wide) and the upper corners rounded with the 10 mm radius (see the figure). The kerbstone surface is smooth, but not slippery. The standard colour is dark grey, but kerbstones in other colours (e.g. white, yellow, red or black) can be delivered upon request for the permanent marking of traffic bans or commands directly on the carriageway. The colour is produced by inorganic pigments mixed with the mass which makes the colour fast and dispenses with any maintenance of periodic repainting throughout their service life.

The COMCON S01 and S01RX kerbstones weigh a little over 60 kg so that they can be put easily into position manually, without any mechanisms.

The COMCON S01 and S01RX kerbstones are placed in a bed of concrete of min. B 20 class which must fill completely their void. This prevents completely the kerbstone displacement by an impact of a heavy vehicle, frequently occurring in case of granite or concrete kerbstones of square or rectanular cross section. The kerbstone void can be used also for various heavy and weak current cables in some cases.

In inverted position the COMCON S01 and S01RX kerbstones can be used also as drainage channels not only for rainwater, but also for heavily aggressive waste water. It should be noted that adequate curved channel elements are hard to find on the market.

The kerbs in the towns and cities where the carriageway is bordered by pavements (sidewalks) on both sides, have been made traditionally of granite in the customary dimensions of 250 x 250 x 1 000 mm and of rectangular cross section. In most cases they were manufactured manually and required quarries affording stone blocks of sufficient dimensions. The number of such quarries is diminishing and due to the contemporary development of motor transport and highway and motorway construction connected with it, which had no analogy in the past, it is only natural that the manufacture of granite kerbs cannot keep abreast of the demand. At the same time also the total tonnage of motor vehicles has increased and their every though undesired impact on the kerb usually results in its displacement and subsequent necessary repair.

The attempts at replacing granite kerbs with concrete products generally ended unsuccessfully for several reasons. Their strength is relatively low and the impact of the vehicle wheel breaks the edges and heavy vehicles displace whole kerbs like in the case of granite kerbs; moreover, in some cases the kerb is broken into two and, last but not least, the effect of de-icing salts, atmospheric factors (freezing and thawing) and acid rains results in their speed surface corrosion, manifesting itself by the spalling of surface strata, origin of unevenness, embossment and general deterioration of appearance. Due to these effects the service life of concrete kerbs is significantly lower and their repeated reconstruction must be undertaken before the reconstruction of the road as a whole is required.

The solution of this problem can be provided only by the application of such materials and components as could be produced by industrial methods while attaining or surpassing the visual, technical as well as a service life characteristics of granite products. Naturally, also the economic aspect plays a non-negligible role.

The invention and development of polymer concretes with their excellent properties have enabled an optimum solution of this problem. Polymer concrete made of high-resistance rock gravels and sands and an adequate synthetic resin yields a material constantly resistant to all factors the kerb may encounter in practice. Due to its discontinued porosity it is not influenced by atmospheric changes; in particular it is entirely inert to the repeated freezing and thawing cycle; thanks to its chemically resistant synthetic binder (on polyester basis, as a rule) it can withstand continuous attacks of de-icing salts and acid rains without deteriorating, and thanks to high mechanical strength (compressive strength of as many as 100 MPa, tensile strength in flexure of as many as 25 MPa) it resists without deterioration the breakage of corners and edges even under very hard and unscrupulous impacts of heavy trucks (camions). The cross-section of the COMCON polymer concrete kerbstone in the shape of inverted channel (U) offers two possibilities: if installed along carriageways with heavy traffic and expected heavy truck impacts the whole channel void can be filled with concrete monolithicized with the concrete bed in which the kerb is always placed. Alternatively the void is left empty and can be used for the simple and well protected installation of cables – electric, telecommunication, signalling, etc. This second possibility is of particular advantage in towns and cities with limited heavy truck traffic or restricted driving speed. The first method of kerb installation, on the other hand, ensures that the kerb cannot be practically ever displaced, as a result of which it is suitable particularly for the roads with very heavy traffic. Advantageous properties and service life of polymer concrete kerbstones have been verified by many (over 15) years´ operation in Prague and other long-distance or ring roads.

The COMCON polymer concrete kerbstones, however, provide a number of further possibilities which could be hardly – if ever – attained by granite kerbs. For instance, it is possible to manufacture curved kerbstones with a wide and unlimited range of inner diameter without any problems and without increasing substantially their price. Further it is possible to produce kerbstones of any colour required, with complete colouring in mass, which remains fast, does not change or fade even after a long service period. This characteristic makes it possible to use coloured kerbs in the places, where conventional kerbs have to be repeatedly labouriously painted, such as in the terminal parts of tramway islands in white, front parts in yellow, prohibition of stopping or standing (yellow, red), parking zones (blue), etc. Moreover, the polymer concrete kerbs can be manufactured with structured surface according to the customer´s requirements to be fitted in the places with the danger of slipping (with longitudinal or transverse grooves, with mosaic surface or irregular grooves). Such types may be of particular significance e.g. on railway platforms and elsewhere.

In a broader context the polymer concrete kerbstones bring about another important ecological effect. They enable comprehensive processing of all wastes of the manufacture of granite components, such as paving setts, border stones, etc. This eliminates the unfavourable environmental impact of granite quarries, viz. spoil banks and dumps which remain an eyesore in the landscape for decades.

For the manufacture of straight polymer concrete kerbstones the company has developed a production line of a capacity of 80 m per shift. At present its last modifications resulting from its trial operation are being completed. This production line will increase substantially (at least double) the productivity of the plant used in the kerbstone manufacture at present and will reduce the number of its operators to one half.