The impact of climate change on mechanical expansion joints between concrete slabs

Climate change adaptation strategies have become increasingly important to Australian engineers, architects and designers in order to remain competitive in the construction industry. While some people remain sceptical of the impact of global warming, the fact is that investors are now looking ahead to how climate change might create risks to their building projects.

As a result, engineers and architects who possess the knowledge and skills to mitigate the damage caused by future climate change are beginning to find themselves at a competitive advantage. While climate change adaptation strategies can be applied across the entire construction industry, one of the ways engineers can address it is through the installation of mechanical expansion joints between concrete slabs.

Why use mechanical expansion joints in Australian buildings

In other parts of the world where seismic activity is more frequent, mechanical expansion joints are often installed to protect buildings from the range of movement between concrete slabs (or other building faces) caused by impact or vibration. However, with Australia being at a relatively low risk of such natural events, why are mechanical expansion joints still used?

Mechanical expansion joints are designed and manufactured specifically for the Australian environment to absorb the thermal contraction and expansion of building materials due to seasonal variation and other environmental factors. This makes them integral to the engineering design of future buildings in the Australian landscape — which has been predicted to demonstrate a noticeable increase in temperatures as a result of global warming in coming decades.

Impacts of climate change on concrete slabs

When concrete is first poured it has a high moisture content. While this is essential to make it workable, the excess hydration can make concrete overly porous and more susceptible to cracks. These micro-cracks emerge after the curing process, as the moisture evaporates and causes concrete to shrink and splinter.

Due to the repetitive stress of heavy vehicular loads or pedestrian traffic, as well as erosion over time, these cracks can worsen and damage the structural integrity of a building.

However, this is not the only way cracking in concrete slabs occurs. Thermal cracking — the strain caused by continued expansion and contraction of concrete due to temperature changes is also a common cause of wear and can shorten a building's lifespan. The future rising heat levels expected as a result of climate change are likely to increase the incidence of thermal cracking and significantly impact on building longevity. Fortunately with the protection of mechanical expansion joints, this risk can be mitigated.

Climate change projections

According to 2030 projections released by the Australian Government, climate change is expected to cause:

• about 1°C of warming, resulting in more heatwaves;
• up to 20% more months of drought;
• up to 25% increase in days of very high or extreme fire danger;
• increases in severe weather events; and
• a sea level rise of about 15cm (between 1990 and 2030).

In addition, Sydney-specific projections outlined in the 2013 Intergovernmental Panel on Climate Change assessment report found that:

• average temperatures will continue to increase in all seasons;
• more hot days and warm spells are expected;
• evapotranspiration levels will be higher;
• the fire-weather climate will become harsher.

These figures — particularly those relating to rises in year-round temperatures — further outline why building products such as mechanical expansion joints will become increasingly essential over time. With concrete so susceptible to cracks and deterioration due to thermal expansion and contraction, these products will become invaluable in adapting to climate pressures, and reduce the risk of structural deterioration - lengthening the safety lifespan of the building.

Industry status on climate change

In November last year, Engineers Australia released their own policy statement which outlined their position on climate change. Their official stance was that the extensive scientific research regarding climate change and global warming is accepted, and that the serious community consequences it will lead to are recognised. Engineers Australia also set out best practice industry guidelines for the adaptation of climate change as it relates to building and construction development.

For Australian engineers, this means the economic considerations pertaining to any project should also factor in the environmental impact of the construction design. It should also incorporate materials which will mitigate the risk of early structural deterioration, such as the proper specification of mechanical expansion joints. While it is acknowledged that this may raise initial construction costs, it must be considered against the reduction in long term maintenance costs.

Adapting to climate change will require careful consideration of climate risks as part of the design and construction of future architectural engineering projects. In turn, this will affect the way building products are selected — with greater emphasis put on incorporating protective building materials such as mechanical expansion joints.

To find the correct expansion joints for your application, Latham has created an online Product Selection Assistant to make the specification process simpler. Alternatively, contact our experienced staff, who will match the right product to your needs.



To find out more about Latham products, please visit www.latham-australia.com. To talk to a Latham product expert, call 1300 LATHAM (528 426) or email sales@latham-australia.com.