Nishimatsu Construction is taking significant strides toward sustainable building practices by utilizing concrete composed of 100% recycled coarse aggregates sourced from their ready-mixed concrete facilities. This innovative approach was showcased on January 29, 2025, when the company announced the successful application of this environmentally friendly concrete at their construction sites.
The initiative, achieved through collaboration with Tamagawa Gakuen and Kume Design, was executed within the timeframe of July to November 2024, marking a pivotal moment in Nishimatsu's commitment to reducing waste and enhancing sustainability within the construction industry.
Construction activities often face challenges related to excess concrete due to overestimations. Standard practices lead to leftover material being returned to plants, creating waste. Nishimatsu Construction addressed this issue head-on, aiming to repurpose this waste. For this specific project, they poured approximately 300 cubic meters of discarded concrete and reused around 270 tons of aggregates through their advanced concrete placement forecasting system and Building Information Modeling (BIM) technologies.
Notably, the recycled aggregate used appears identical to traditional materials and retains comparable strength and properties. According to Nishimatsu Construction, their testing revealed no significant differences. "The concrete utilizing 100% recycled coarse aggregates showed results equivalent to base concrete using conventional aggregates. Fresh properties and compressive strength were comparable," stated a company spokesperson.
Usually, the industry regulates the use of recycled aggregate's effective utilization—permissible up to 20% substitution for foundations and major structural components. Despite this allowance, the incorporation of such materials has been limited, primarily due to perceived disadvantages and lack of demand. Nishimatsu's undertaking not only meets regulatory standards but also actively challenges industry norms, cultivating broader acceptance of recycled materials.
This initiative contributes meaningfully to the circular economy by rethinking how waste materials are managed within construction operations. Nishimatsu aims to minimize the environmental impacts associated with traditional concrete pouring by increasing the use of recycled aggregates, signaling important shifts toward greener construction practices.
Indeed, the construction industry faces formidable sustainability challenges. Events like earthquakes, climate change, and resource scarcity heighten the urgency for impactful change. This project highlights how traditional methods can evolve to adapt to current environmental needs.
By leveraging technology and embracing innovative approaches, Nishimatsu Construction is paving the way for future projects, potentially influencing industry standards and practices across Japan and beyond. Their efforts not only reduce waste but contribute to the greater responsibility of mitigating environmental degradation caused by construction activities.