Recycling Pavers in Rotterdam
You might also wish to see a Total Quality pavement design method, permeable paving in Brazil, a history of paving through the ages and design notes for roads surfaced with pavers.
During June 1997, JK visited engineers at Rotterdam City Council in order to inspect their concrete block paving operation. Rotterdam was the world's first city to introduce concrete block paving, as a temporary expedient replacement for scarce brick pavers in 1948. Today, pavers are Rotterdam's most commonly installed road surfacing material, having recently surpassed bituminous materials. The pictures here show how pavers are removed from streets, cleaned, sorted, repacked, then delivered to a new street paving project. There, they are installed mechanically. The installation machine lifts layers of pavers by suction. Note how the laying course material (bedding sand) is screeded - the heavy screed hopper is towed by tractor and the weight of the hopper achieves compaction. The result is a street surfaced accurately and cost effectively with antique effect pavers. In 1997, 80% of all Rotterdam's paving work is carried out by this method.
This first picture shows a machine which takes dirty jumbled pavers, cleans them, packs them into layers in a herringbone pattern and cubes and shrink wraps them. Its not as sophisticated as it appears. Two men inside reorientate the pavers, but the system of conveyors reduces their effort to a minimum.
The next picture shows the pavers ready for reinstallation in a Rotterdam street.
Before the recyled pavers can be relaid, bedding sand is screeded and compacted by the device shown below. The weight of sand in the hoppers compacts the screeded sand. The machine's wheels run on plastic strips placed on the adjoining pavers to ensure accurate levels.
Below, a typical Rotterdam residential street is being repaved with recycled pavers. The pavers are laid into a thick layer of sand. In other countries, a roadbase and sub-base is usually provided. Although the Rotterdam system will need to be relaid in possibly 7 years, this nonetheless represents good engineering practice. The natural peat beneath the sand would cause other forms of roadbuilding to suffer early distress. This Rotterdam system is an example of appropriate engineering.
The machine shown below takes the recycled pavers, lifts them by pneumatic suction and swings them into place on the screeded sand. Mechanical installation is mandatory in The Netherlands where Health & Safety regulations prohibit the manual installation of pavers thicker than 80mm.
Below, the paving machine is picking a layer of pavers from one of the cubes from the recycling station. Suction is applied to each individual paver and clamps around the side pat the pavers into the correct shape. The pavers have been repacked in a herringbone pattern.
And finally, the pavers are placed on the screeded bedding sand. Most of the pavers are installed by this means with the edges filled in by hand laying. The result is a street using antique effect recycled pavers. The defects in the pavers are considered to add to the character of the street. Indeed, in the UK, specially tumbled new antique pavers sell for a premium.
In this case, the plastic band which held the pavers together is inadvertantly left in the bedding sand. Some would view this with horror but the pragmatic Dutch appear not to be concerned.
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