installation techniques . In essence , a hydraulically operated clamping system is used to lift a ‘ cluster ’ of concrete paving blocks – generally around 1 square metre in area and already in the required laying pattern . Clamps can be fitted to a variety of site equipment or form an integral part of dedicated machines designed for good site manoeuvrability . While the machine does all the work , there is sometimes an operative guiding the cluster into place , in addition to the machine operator .
All kinds of block shapes and styles , including standard rectangular , can be machine laid in various patterns including herringbone which some manufacturers offer ready for machine laying . The speed of laying depends very much on site organisation , travel distances , machine types and other factors . But 1,500 square metres or more per day should be achievable – contrasting with no more than 50 square metres per person for manual laying . Productivity is comparable with asphalting operations and the ability to deploy a block laying machine and crew at short notice to meet ‘ just in time ’ demands on sizeable projects is a major advantage .
But there are benefits in using the technology on modest sized projects ,
as well as larger schemes . Faster installation means earlier completion and less operational downtime of the paved area – not forgetting that block paving can be used immediately after completion without curing times . Machine installation also makes it easier to achieve consistent accuracy and uniform joint widths as it is less tiring for operatives . To maximise the efficiencies of mechanical laying , installation contractors adopt a similar approach with all the site processes , such as mechanising other operations including laying and screeding the laying course , and delivering blocks close to the laying face .
Safety and Efficiency The same concept can be applied to other precast concrete paving products to improve safety as well as efficiency . Concrete kerbs have been in use for around 70 years and concrete flag paving for even longer . Regulations have been in place for some time to protect workers from risks associated with musculoskeletal and upper limb disorders resulting from manual lifting and installation of these products .
Elimination of manual lifting should be considered at the design stage so that kerbs and flags are always handled and laid mechanically using vacuum lifting gear , mechanical grabs or similar devices .
Where manual handling is unavoidable , workers should be trained in good handling techniques . The use of lighter weight kerbs or devices that allow two people to share the lift will reduce the risk of injury . Using smaller and lighter kerbs or flags , or substituting flags with block paving will further reduce the risks from any residual manual handling .
Another area where safety measures offer other cost and efficiency benefits is the elimination of cutting concrete paving products . Silica is a natural component found in many construction products : crystalline silica is found in sand , sandstone , granite and concrete . Health hazards can result from breathing in the fine dust of crystalline silica . But this risk can be eliminated when installing concrete paving blocks , flags and kerbs – either by removing the need to cut concrete products or by utilising safer cutting practices and equipment .
Modular Nature It is important to remember that the key to attractive , durable , cost-effective precast concrete paving is to optimise its modular nature , by dimensioning areas to minimise cutting and combining compatible products to avoid it . There are numerous techniques and special products readily available to help with this , as well as different styles of precast concrete kerbs , channels and other components . Consideration of all the product alternatives and sizes available at the design stage , and careful setting out can generate real efficiencies and eliminate the need for cutting .
As with any construction operation , the devil is in the detail – with edges , insertions , level changes and junctions within paving , which should not just be left to on-site operatives but resolved off-site within the design .
Mechanised installation techniques using either dedicated machines or attachments to standard site equipment can dramatically improve productivity .
For all types of modular concrete paving , well-established guidelines and case studies are readily available from Interpave ’ s information resource : www . paving . org . uk
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