Interview Marco Schravesande and Sander Jonker: A quick tidy-up: 38,000 tonnes of rubble

This material used to be covered by cars, but the vehicles that will soon be parked on it will be cargo planes. We are, of course, talking about the concrete from the former P2 car park that had to be demolished to make way for the new pier and terminal. Tens of thousands of tonnes of rubble were transported from that location to the future site of the South-East apron, where the concrete was ground up to form the foundations of a new cargo site.

Marco Schravesande

Giving old concrete a new lease of life

The old P2 car park was the second largest parking garage in Europe until it was demolished last year to free up the site for the upcoming new terminal. Project Manager Marco Schravesande wanted to find a new purpose for all those slabs of concrete. ‘We had 38,000 tonnes in total,’ he recalls. ‘In terms of weight, that’s about the same as 100 Boeing 747s. Coincidentally, a new construction project was just beginning outside the centre of Schiphol: the South-East apron.’ Marco adds: ‘And that project needed a lot of concrete.’

Future location for freight traffic

The South-East apron will serve as a new location for freight traffic, including a freight centre, six aircraft stands and a brand-new taxiway to Runway 06-24. According to Project Manager Sander Jonker, the project will require around 130,000 tonnes of rubble. ‘Right now,’ he says, ‘the site of the apron is just some derelict land we’re in the process of decontaminating. Once we’ve got everything ready, we’ll need a firm, stable layer measuring 50 centimetres CTB (cement-treated base) for the gate parking areas and 75 centimetres for the taxiway.’ That CTB is made up of concrete rubble, with any gaps being filled with sand, cement and water. ‘Another 40 centimetres of concrete will be poured on top of that CTB layer for the aprons; the taxiways will be covered in asphalt.’

From parking garage to apron

Looking at the South-East apron as it is now, you could be forgiven for thinking you were in the Alps – the mountains of concrete rubble are enormous. ‘That’s to be expected, as about 99% of the former P2 parking garage is currently piled up here,’ says Marco. Sander echoes his comments: ‘And of course there’s also material from a lot of other construction and demolition projects. We wouldn’t have had enough if we’d only used the material from P2.’

We know where it came from

It’s a real benefit for Schiphol that the concrete from the former P2 parking garage can be used for the new cargo apron. ‘You have to pay someone to take rubble away,’ Marco explains, and Sander adds: ‘The same applies to buying new rubble. So with this situation we’ve saved a lot of money on both projects.’ Marco sees another big advantage. ‘When we use crushed construction debris for new projects, we have to satisfy all sorts of requirements and certifications. When the material is sourced from our own buildings, we know where it came from. That gives us a guarantee that we’re using pure materials that meet the legal standards, such as the requirement to achieve a secure level of strength.’

Sustainable construction

In re-using the rubble from P2, Schiphol is taking the most sustainable path. ‘Re-using the material at the airport means that little or no extra raw material will be wasted,’ says Marco. ‘It also saves on transportation, fuel and pollution. ‘There is now a mobile crusher at the site of the new apron.’ Sander explains: ‘We use the crusher to grind up the concrete into rubble as it comes in. It gets crushed into granules measuring anywhere from a few millimetres to four centimetres. When we mix those granules with fresh cement, we have a solid foundation for our construction project.’ But why is the quality of the rubble so important? ‘Schiphol’s new apron will be available for use from the end of August 2019, and we intend for it to remain in use for the next 50 or 60 years. At least.’

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