Technical Regulations

Technical guidelines and Rules and Standards are part of any contract agreed with public service clients. With private clients, too, however, it is advisable to work according to these basic principles and this does mean complying with these rules and standards. When planning and carrying out pavement work with clay pavers suitable for traffic the following contract and delivery conditions norms and guidelines should be respected. DIN norms can be acquired from the firm Beuth-Verlag in Berlin. All other technical regulations, unless otherwise specified, are published by the Research Institute for the Road and Traffic Industry (FGSV) and may be ordered from their publishing house, FGSV- Verlag.

Below you will find the most important parts of the Technical Regulations for the Building of pavements with clay pavers suitable for traffic as excerpts and with short explanations.

The following regulations for clay pavers are significant :
• ATV DIN 18299 General Regulations for construction work of all types
• ATV DIN 18318 Traffic route engineering, pavements and paving in an unattached form and edging

The general technical rules and standards for contracts describe the usual execution of the work and are the basis for the calculation, completion and accounting for clay paver work with the VOB contract. This includes: “ Clay pavers and bricks are to be laid flat in rows with offset joints and joint widths of 3 to 5 mm on a base or in the base. Joint axes must show a continuous course.” This means that in ATV DIN 18318 it is assumed that the clay pavers will be laid horizontally in rows, unless something else has been agreed on. The horizontal laying is the basis of the calculation and the acceptance of the work, unless a different form of laying was agreed on in the technical specifications e.g. upright laying. Further: “The base must have a thickness of 30 mm -50 mm in the compacted state. Mixtures of stone grain size 0/4, 0/5 or 0/8 are to be used as base materials.” The bedding material must be such that it is permanently sufficiently permeable and stable in its filter function in relation to the foundation. The closing of the joints must be carried out continually with the progress of the laying of the pavers. To close the joints the grouting is to be laid on the pavers, swept into the joints and where required sluiced into the joints with a limited amount of water; superfluous grouting should be removed. Subsequently the surface should be stabilized using vibration. In the case of pavers with a special surface (e.g. coloured pavers) particular protective measures should be taken e.g. plastic sheeting under the vibrating plate. The joints should be refilled if necessary. Finally a fine-grained grouting should be swept and sluiced onto the surface to close the joints. A grain size of 0/2 is suitable.

The resulting slope of the pavement and the covering should not be less than 2.5%. If a final slope was planned this should be agreed on in advance and taken into consideration during the planning.

TL Pflaster-StB-Technical delivery conditions for construction products for the building of clay paver surfaces, flagging and edging.

 When paving work is being carried out on the basis of ATV DIN 18318 -Traffic route engineering, clay paver surfaces and paving- the classes of the Technical Regulations for paves (TL-Pflaster-StB) are to be conformed to. These classes are automatically valid in construction contracts with standard design according to DIN 18318 unless other agreements are specified in the contract. The highest class-in the DIN EN 1344 is to be complied with when the work is being done within Germany. This means in detail:
• measuring span –class R1
• flexural strength – class T4
• abrasion resistance- class A3
• dew frost resistance- class FP100
• slip/skid resistance –class U3 

ZTV Pflaster-StB-Extra technical conditions of contract and guidelines for the production of pavement, clay paver surfaces and edgings.

The ZTV content only becomes valid if and when the individual contract conditions are specifically mentioned in the construction contract. In the case of construction projects authorized by the German Federal Government/Institutions the ZTV Pflaster-StB is obligatory; where the individual Federal States are responsible it is recommended. Private persons are advised to use the ZTV at least where the areas will be subject to traffic.

Pavement can be used for all traffic areas following the in accordance with RStO. Flagged paving on the other hand should only be used for pedestrian and cycle paths, apart from road crossings, as well as for areas without any motor traffic. ATV DIN 18318 presumes the laying of clay pavers in rows as the norm. Laying flags with cross joints requires, in accordance with ZTV Pflaster-StB 06, the express consent of the client. The addition of flags and pavers should only be carried out when cut wet. This is to prevent a sloppy appearance of the finished area and any cracking of flags or pavers.

• Instruction leaflet for paved areas with pavement and flagging in unattached layout and their edgings.(MFP)
• Working paper for paved areas with pavement and flagging in attached layout.
• Instruction leaflet about slip/skid resistance for flag covering in areas for pedestrian traffic

The content of leaflets and recommendations claim to be state of the art. Working papers, on the other hand, largely reproduce the current stage of research or further activities. If these texts are agreed on, the relevant content must be incorporated into the performance specifications.   A general contractual agreement is not envisaged.

The instruction leaflet for paved areas with pavement and flagging in unattached layout and their edgings.(MFP) complements the Technical Rules and Standards. Construction guidelines for the planning and execution of base and paving e.g. base course, as well as specific recommendations for the choice of paving and flags including bedding and grouting material may be taken from this leaflet.

Recommendations for the minimum infiltration value should ensure a sufficient permeability of the base. To ensure that powdering as a result of traffic use doesn’t occur only construction material mixtures should be used which offer a sufficient resistance to grain splitting so that a sufficient permanent permeability of the base course is assured. In the MFP definite recommendations on the grain splitting value of construction material mixtures for base course, bedding and grouting materials are offered in the form of category SZ according to the TL Stone-StB 04, attachment H.

When using clay pavers the elbow pattern, herring-bone pattern, elbow pattern diagonal to the path, stretcher or row bond diagonal to the path or at a 45 degree angle are the preferred patterns. Layout with cross joints or continuous joints in the direction of the path are generally unsuitable to prevent distortion. Such layouts are generally only suitable for areas on which there will only be occasional vehicular traffic.

RStO-Guidelines for the standardization of the superstructure of areas used for traffic.

The standard thickness in the relevant constructional classes III (now Bk1.8 and Bk3.2) is 10 cm and in the constructional class IV (Bk1.0), V and VI (Bk0.3) 8 cm in each case. For clay pavers with a lower thickness the exception according to section 3.3.5 pavements is to be followed.   Here it says: “Lower paver thickness, not however less than 6.0 cm, can be used in the case where sufficient experience of local construction methods is present.” The tightening of the requirements in relation to the load-bearing capacity of the gravel base course should be followed. The Ev2 value for constructional class Bk3.2 has been raised to >180MN/m². In this case great care should be taken through suitable material choices that the higher compaction doesn’t lead to a loss of permeability.

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