Introduction

IAs economies around the world evolve, countries make significant investment into setting infrastructures which plays a catalysing role in boosting the economy. Governments in low and middle income countries around the world invest between 3.4-5 percent of their Gross Domestic Product (GDP) in infrastructure every year.¹ Despite the significant investment, the quality and adequacy of infrastructure varies largely from one country to another. Millions of people and businesses often need to bear consequences of over strained or fragile infrastructural arrangements which are stretched to limit during any natural hazard. Estimates suggest a potential USD 250 billion loss in assets and USD 1 trillion at risk over the next five years from climate impacts.²

Climate Resilient Infrastructure

Climate resilient infrastructures are defined as an architecture, which is planned, designed, built and operated in a way that anticipates, prepares for, and adapts to changing climate conditions. It is estimated that an average of 3% additional upfront capital investment is required to build esilience into infrastructure, yet every dollar invested in resilience generates four dollars of economic value. ³

Resilience through Concrete Infrastructure

Cement concrete infrastructures has stood through the test of time as more climate resilient than any other building materials. Some of the prominent apsects that make concrete the most preferred builing material are detailed below:

1. Versatility

   Concrete is highly durable,inert, fire resistant and resilient. As a material, concrete is versatile across many parameters, including its constituents, composition, method of manufacture, product range, method of placement, and exposure conditions. Concrete allows multiple structural design alternatives, compressive strength (10-100 MPa), types of reinforcement (fibres, ferrous bars, or non-corroding reinforcement). Such versatility allows multiple applications optimising resource efficiency and externalities.

2. Thermal inertia

   Concrete, when not painted soaks up excess heat during the day time to reduce the need for mechanical cooling. This heat retained by concrete is released during the night through the circulation of cool evening air. It is estimated that concrete’s ability to store energy could help reduce a building’s heating and cooling demands over its service life by up to 8%.⁴

3. Placement

   Concrete allows a variety of placement alternatives which includes self compacting concrete, fabric formwork, pumped concrete, large volume pours and sprayed concrete, among others.⁵ Prestressing the concrete minimises the volume of material required for construction, thereby also reducing associated transportation.

4. Cement recarbonation

   Recarbonation is a natural process, wherein concrete absorbs the CO₂in the air. It is estimated that the carbon sink provided by a cement concrete structure is about 50% of the process CO2 emissions released during cement production.⁶ Recarbonation occurs relatively quickly in non reinforced products or thin/porous applications when compared to reinforced concrete and thicker elements.

5. Low embodied emissions

   Byproducts from other industries, such as fly ash and ground granulated blast furnace slag (GGBS), can be used to partially replace clinker in cement thereby reducing the embodied emissions in the construction material.

6. Ground water recharge

   Porous concrete can help to reduce the risk of flooding in urban areas, draining and filtering rain away from the surface. Porous concrete is produced with little to no fine aggregate content and typically comprises of 15-25% voids, which allow water to flow through the concrete and sink into the ground.

7. Reflectivity

   Albedo is the measure of the fraction of solar energy reflected a surface. Lighter colour surfaces reflect light and have a high albedo, while darker surfaces absorb light and have a low albedo. Concrete has an albedo of 0.4, which enables it to reflect relatively more of the sun’s radiation than some of the other building materials such as asphalt, thereby moderating the warming impact of solar infrared rays.

Conclusion

Climate resilient infrastructure has the potential to improve the reliability of service provision, increase asset life and protect asset returns. Government can play a catalysing role in encouraging climate resilient infrastructure. Public procurement processes can act as templates requiring bidding entities to consider climate resilience when bidding projects (by accounting for costs over the asset’s lifetime under alternative scenarios). More and more stakeholders today are realising the significance of imbibing climate resilience in infrastructure to protect critical socio economic infrastructure and interest of citizens.