The lifecycle of concrete can be broken down into few stages:

1. Raw Material Extraction:
   • Components: Concrete is primarily composed of cement, aggregates (sand, gravel, crushed stone), and water.
   • Extraction Impact: The extraction of raw materials, especially limestone for cement production, has significant environmental impacts, including habitat destruction and resource depletion.
2. Manufacturing:
   • Cement Production: Cement manufacturing is the most energy-intensive part of the concrete lifecycle, contributing to approximately 8% of global CO2 emissions . The process involves heating limestone in kilns to produce clinker, which is then ground to make cement.
   • Energy Use: The high energy consumption in cement production results from the fuel used to heat kilns and the chemical reactions that release CO2.
3. Transportation:
   • Material Transport: Transporting raw materials to production sites and concrete to building sites involves additional carbon emissions.
4. End-of-Life:
   • Demolition and Recycling: At the end of its useful life, concrete can be crushed and recycled as aggregate for new concrete, reducing the demand for new raw materials and lowering the carbon footprint.

Conducting a lifecycle assessment (LCA) of concrete helps quantify its environmental impacts at each stage. Here in New Zealand, where sustainability is a growing priority, understanding these impacts is essential for making informed construction choices.

1. Carbon Emissions:
   • Cement Production: The largest source of CO2 emissions in concrete’s lifecycle. Innovations in low-carbon cement and alternative fuels are being explored to mitigate these emissions. Here in New Zealand companies such as Allied Concrete with their Ecrete product, or new players Neocrete,  amongst others are offering viable eco-friendly alternatives.
   • Overall Impact: While concrete has a high initial carbon footprint, its long-term durability can result in lower overall emissions when compared to materials that require frequent replacement.
2. Energy Consumption:
   • Production Efficiency: Advances in energy-efficient manufacturing technologies and renewable energy sources as highlighted above can reduce the energy consumption associated with concrete production.
3. Mitigation Strategies:
   • Use of Supplementary Cementitious Materials (SCMs): Concrete NZ is undertaking research into SCMs which incorporate fly ash, slag, and silica fume in concrete mixes can reduce the amount of cement needed, lowering the carbon footprint.
   • Innovative Products: Our own QPOD void formers are an example of how innovative products can enhance the sustainability of concrete foundations by reducing the volume of concrete required without compromising structural integrity.