When it comes to new airport runways, the dream is to achieve a pavement design that is smart, innovative, low maintenance, sustainable and fast to construct writes world-leading pavement specialist Dr Bachar Hakim.
As airline passenger numbers continue to grow – exceeding four billion worldwide for the first time in 2018* – there is increasing pressure on airports to optimise their existing assets and expand to meet demand. And this trajectory looks set to continue with a stream of new and replacement airports such as the New Airport Istanbul, Beijing Daxing International Airport and Jewel Changi Airport, Singapore along with expansion of others including Los Angeles International, Kuwait International and London Heathrow.
Against this backdrop of rising demand is the reality faced by asset owners. Budgets are being stretched, worker and passenger safety thankfully has risen to the top of the agenda, and we see the introduction of ever-tougher environmental regulation on noise, air pollution, low-carbon infrastructure and sustainability. In response to these new pressures the industry must find innovative ways to deliver increased and improved capacity and service. Long-term infrastructure resilience needs to be achieved through using innovative materials, construction and monitoring techniques, digital technology and asset management .
Key to accommodating greater passenger capacity is the runway. Existing assets must perform better, last longer, and be maintained more easily and efficiently, and new runways can benefit from recent innovations in design, materials and construction.
So, there are many, many reasons why airports need a fresh and revised approach to their most important asset – the runway.
Here are three key runway innovations and approaches to help airports meet growing demands.
One of the most significant recent changes in UK aviation is the introduction of BBA – the French airfield asphalt concrete material Béton Bitumineux pour chausées Aéronautiques. This offers a viable, faster to construct, cost-effective alternative to conventional asphalt surfacing. BBA provides an improvement on the conventional approach to runway rehabilitation/resurfacing as it can be laid without grooving and can be open to traffic with minimum delay. With its open-texture macrostructure, there are advantages during operation too, because this surface requires less rubber removal during runway life.
Still in the relatively early days of development, numerous innovations are being created to improve asset monitoring. These include embedding technologies in the pavement, settlement monitoring, improved data collection, self-healing asphalt and concrete, harvesting energy from aircraft friction, and pollution-absorbing materials. At the forefront of this work is AECOM’s Centre of Excellence for Pavement Asset Management which has the key aim of creating innovative design to help improve whole life cost and sustainability. The team is one of the largest in the world, based in Nottingham and providing services for airports around the globe. With the goal of transferring research into practice, the team operates a cradle-to-grave service. This comprises the whole lifecycle of pavement infrastructure from designing new pavements, specifying the materials, testing during construction for quality, surveying and monitoring existing pavements to assess performance, asset management, deterioration modelling, treatment prioritisation and finally research and development to update/rewrite the design standards.
At Hong Kong Airport for example the team’s recent research work has included the development of a stone mastic asphalt specification for airfield taxiways, investigations into cracking of the north runway pavement, and a feasibility study on the use of reclaimed asphalt pavement materials in runway foundation layers.
Environmental and economic sustainability are major considerations for today’s airport owners and great progress is being made. As mentioned above the reuse of recycled materials is becoming an accepted practice.
An impressive example of the first cold asphalt recycling in a UK runway is at RAF Waddington. Following a full pavement evaluation of the existing runway it was clear that rehabilitation was required to replace the concrete ends and the disintegrating tar-bound asphalt layer. Because tar-contaminated material is very expensive to dispose of, we developed a foam-mix asphalt design to allow on-site ex-situ recycling to encapsulate the tar for use in the lower (base) asphalt layers of the runway.
*According to the International Air Transport Association (IATA), global scheduled passenger flight numbers are forecast to top four billion for the first time this year with anticipated revenues for commercial airlines of almost $750 billion. According to the IATA, passenger demand remains strong and is “well ahead of both the five- and 10-year average rates (6.4% and 5.5%, respectively).