Royston Sim Straits Times 8 Apr 13;
AIRCRAFT parking spaces at Changi Airport are being ripped up and replaced with recycled concrete mix as part of an ongoing drive to go green.
Thirty-one of the 80m by 80m spaces - officially termed stands - will be repaved over the next 10 years.
Concrete aggregates extracted from the spaces, which are nearing the end of their lifespan, are used to form a new mixture. This material - which is as good as new, will be used to replace the 31 stands at Terminal 1, Terminal 2 and the cargo area. There are a total of 146 aircraft parking stands at the airport.
Mr Teoh Eng San, assistant vice-president for engineering and development at Changi Airport Group, said the company "has to be prudent and rehabilitate our parking stands at appropriate times".
He added that the pavement has an average lifespan of about 20 to 25 years, depending on factors such as usage, and wear and tear.
The stands at the airport have been in use for more than 30 years - longer than average - because of high-quality construction and rigorous maintenance work.
The airport engaged engineering experts from the National University of Singapore (NUS), who developed a mix in which 20 per cent was recycled concrete.
Eight parking stands were replaced using it under phase one of the project.
The Building and Construction Authority has set a benchmark of 20 per cent to encourage wider use of recycled materials in the construction industry.
With the backing of Changi Airport Group, the NUS team went a step further and formulated a new mix that had 40 per cent of recycled concrete aggregates - a first here.
NUS professor Fwa Tien Fang, a consultant for the project, said the high quality of the concrete used in Changi's stands makes it suitable for recycling.
As parking stands are key airport structures, Prof Fwa said rigorous testing was done to ensure the new mixture was as strong and long-lasting as fresh concrete.
"When we use recycled material, we must make sure there is no compromise on quality," he said.
Mr Teoh said the main advantages of using recycled concrete include alleviating waste disposal issues in land-scarce Singapore and moving towards environmental sustainability.
He added that the cost of using recycled concrete to repave the parking stands is about the same as if fresh concrete was used.
However, he noted: "A major consideration for the team is the pursuit of green measures in using recycled concrete aggregates and doing our part to preserve the environment."
The project consists of four phases and should be completed in 2019. The second phase, which will see 10 parking stands repaved with the new 40 per cent mix, is currently under way.
New aircraft stands will also be constructed at Terminal 4, and Changi Airport Group has announced plans to convert a 38ha land plot into an aircraft parking area. These measures will increase Changi's parking capacity by more than a fifth.
Mr Teoh said the group will consider using recycled concrete for new construction projects where feasible.
