Given its near ubiquitous usage as a construction material in the modern world, increasing the durability and service life of concrete plays a critical role in raising the sustainability of society’s built environments.
This is particularly the case in Australia, where unique environmental conditions in the torrid coastal country can have a wide variety of adverse effects upon the quality of building materials.
Mark Hanlon, senior director of business development with sustainable concrete solutions provider Xypex, points to a broad range of environmental factors in Australia that can negatively affect the durability and quality of concrete
These include a coastal chloride environment that accelerates concrete deterioration, extreme ranges of high and low temperatures that can cause issues with curing and cracking, limited availability of consistent, quality aggregates that can result in the production of poorer quality concrete, and the high saline soils of certain major population centres, such as the suburbs of Adelaide.
In addition to this, the very nature of urban and infrastructure development in Australia can cause problems for concrete durability. Its major cities make extensive use of built environments such as tunnels and car parks where carbonation is accelerated, while the reclamation of land for infrastructure purposes in the many parts of the country that are situated adjacent to oceans and rivers also results in hastened deterioration due to the aggressive acid sulphate soils of such sites.
According to Mark Hanlon, while Australia's building sector is already making efforts to improve the sustainability and durability of concrete structures, there is still much more work that needs to be done within the industry.
"We are heading in the right direction, particularly with credible organisations becoming involved in the improvement of Australian standards, such as the Concrete Institute of Australia with the presentation of its durability committee papers, and the lobbying of government authorities," he said. "But we are still only scratching the surface...we should be pushing more towards improved 'performance based specifications and raising current acceptable standards."
Mark Hanlon advocates the use of the latest proven technologies for raising the durability and strength of concrete structures within the challenging environmental conditions of many parts of Australia.
"The addition of hi-tech admixtures to new structures or as coatings for existing structures can restrict the movement of moisture into concrete, thereby reducing deterioration processes such as the corrosion of steel reinforcement as a result of carbonation and chloride ingress, and the disintegration of the concrete matrix due to alkali-aggregate reactions, or reactions with sulphates and other chemicals," he said. "[Hi-tech admixtures] also have the additional benefit of providing crack healing capabilities, that creates an improved and more resilient concrete."
"The reduction in future maintenance costs have a hugely positive economic, social and environmental impact, thus creating a more sustainable future for our country."