Japanese contractor Obayashi has been advancing the use of its low-carbon concrete, CleanCrete, in Japan and exploring opportunities for its application in overseas markets. The product significantly reduces CO2 emissions by replacing most of the cement with industrial by-products such as ground granulated blast-furnace slag. As of the end of FY2025, CleanCrete had been used in approximately 479,000 cu m of concrete domestically.

However, overseas deployment presents challenges, noted Obayashi, as material performance, quality standards and climatic conditions differ from those in the domestic market. Therefore, mix designs and quality control methods established in Japan cannot be directly applied in other countries.

In Indonesia, Obayashi tailored CleanCrete to locally available materials as well as local production and construction requirements, while ensuring strength performance, workability and cost efficiency together with CO2 reduction.

Local production system

In collaboration with Pionirbeton Industri (PBI), a major ready-mixed concrete supplier in Indonesia, Obayashi conducted a series of tests to support the local production and adoption of CleanCrete. Through these efforts, a mix design using locally sourced materials was created, making it suitable for local production and construction requirements while maintaining a cement content of less than 30%, consistent with its mix design in Japan. This locally produced CleanCrete reduces CO2 emissions by more than 60% compared with conventional concrete, said Obayashi.

The product, manufactured at PBI’s ready-mixed concrete plant, has been incorporated into the foundations of a temporary building at a data centre construction project as a pilot application. It was transported to the site and poured using a concrete pump truck. According to Obayashi, there were no issues with workability, no cracks or other defects were observed on the finished surface, confirming that the concrete could be placed to a satisfactory standard.

Going forward, Obayashi will leverage the knowledge gained through this initiative to further optimise mix designs tailored to local environments. The company aims to expand the adoption of CleanCrete in construction projects across Indonesia, including the data centre development where the pilot application was carried out.