Semarang-Demak Toll Road Bamboo Could Become Coral Reefs

Bamboo used as the material for the toll road mattress over the sea in the Semarang-Demak Toll Road apparently serves not only as a foundation. Quoting the official website of the Toll Road Regulatory Agency (BPJT) of the Ministry of Public Works (PU) on Monday (11/05/2026), those 10 million bamboos contribute to the sustainability of the marine ecosystem. The bamboos were sourced from Wonogiri, Magelang, and Purworejo in Central Java Province. Not just any bamboo, the ones for the project also have specific criteria: straight bamboos with a length of 8 metres and a diameter between 8-10 centimetres. The Semarang-Demak Toll Road is divided into two sections. Section 1 from Semarang to Sayung stretches 10.64 kilometres over the sea and is still under construction. Meanwhile, Section 2 from Sayung to Demak, 16.31 kilometres long on land, is already operational. The Semarang-Demak Toll Road will be integrated with the sea dyke, where the embankment structure over the sea is reinforced by a 17-layer bamboo matras. The Building Materials and Structure Centre of the Directorate of Settlement and Housing Technical Development, Directorate General of Human Settlements, has conducted testing to measure the feasibility of using bamboo material. The construction work on Section 1 Semarang-Demak package 1B, which is over the sea for approximately 10 kilometres, uses bamboo matras as the foundation and requires around 10 million bamboo poles woven by 1,500 skilled workers. Road Pavement and Asphalt Observer, Purnomo, explained that bamboo has characteristics that make it suitable for use in watery or muddy environments. “The nature of bamboo, if soaked in water for 100 years, will not be damaged or rotten,” Purnomo told Kompas.com on Tuesday (14/04/2026). He stated that building in swampy areas with muddy and soft soil conditions presents its own challenges. If directly filled, the soil tends to be unstable and can shift. “To overcome this, the soil is piled with dolken wood. In Java, dolken is not available, whereas bamboo is abundant,” he explained. Because of its plentiful availability, bamboo is then utilised as an alternative. Bamboo is driven into the ground to increase load-bearing capacity, then arranged into a matras as the base for the embankment. “So we utilise that bamboo. We drive the bamboo and on top of it, make a matras as a good base for the road body embankment,” Purnomo said. With this method, the soil structure becomes more stable, thus able to support the road construction on top of it.