Kavishan Ranatunga: Building a Greener Future: Innovating Low-Carbon and Durable Concrete for Aotearoa’s Infrastructure
Concrete is a widely used construction material globally and significantly contributes to greenhouse gas emissions, primarily due to cement manufacturing. While the global concrete industry has increasingly adopted alternative materials to reduce emissions, New Zealand, lacking heavy industrial resources, must explore local options. This study investigates the performance of concrete incorporating locally sourced volcanic materials—pumice and tephra—from New Zealand as partial cement replacements. Both materials were ground and used to replace cement in concrete mixtures at rates of up to 30%. Fresh and hardened concrete properties were measured to evaluate the performance. A life cycle assessment (LCA) was conducted to evaluate the global warming potential based on three batching plants. Results showed that cement with pumice or tephra could contribute to low-carbon concrete solutions in New Zealand. As a world-first trial application, a footpath was built using this concrete mix, showcasing its viability in real-world infrastructure.