Guangzhou-Shenzhen Expressway serves as a critical artery connecting two of the Pearl River Delta's most dynamic urban centers. It plays an indispensable role in regional transportation. As the expressway's renovation and expansion project advances, bridges that no longer meet current navigation and regulatory standards must be demolished and rebuilt. This has created a significant challenge: managing the massive volume of concrete waste generated from these aging bridge structures.
The Guangzhou-Shenzhen Expressway renovation project sits in the heart of the Greater Bay Area's core metropolitan region. It is being implemented in two segments: the Sui-Guan section and the Shenzhen section. The Sui-Guan section alone stretches 71.1 kilometers and is expected to yield approximately 600,000 cubic meters of discarded bridge components during demolition. That volume equals enough material to fill 240 standard Olympic-sized swimming pools. Traditional disposal methods such as on-site burial or decentralized processing present serious problems: they generate significant dust and noise pollution, and the valuable land along the route simply cannot accommodate dedicated waste dumping sites.
In response to these constraints, the project has aligned itself with the national "dual carbon" strategy. It has embraced the Ministry of Transport's "one network, four modernizations" framework and adopted a green transformation approach. The team pioneered a new model of "centralized recycling and high-value utilization" by establishing a dedicated concrete green recycling center within the interchange area. They developed the industry's first remote, unmanned precision processing production line for recycled concrete aggregates. Old bridge components are now processed on-site into high-quality recycled aggregates that feed directly back into the roadbed stabilization layers, guardrails, and other cement concrete structures of the expanded expressway. This innovative system effectively resolves the solid waste disposal challenge inherent in renovation projects.
According to Zeng Siqing, deputy director of the project management office, the recycled aggregate utilization rate has already hit 100%. The project is expected to save 1.4 million tons of natural sand and gravel, reduce annual carbon emissions by approximately 23,000 tons, and generate direct economic benefits exceeding 100 million yuan. The social, environmental, and economic returns are all substantial.
Stepping inside the concrete green recycling center, the production workshop operates with zero on-site personnel. Robotic arms, automated crushing lines, sealed negative-pressure dust collection systems, and fine powder recovery units all run in seamless coordination. The recycling center spans approximately 26,000 square meters and comprises a storage area, primary crushing workshop, backend processing hub, and finished product warehouses. The journey of "rebirth" for old bridge components begins in the primary crushing workshop, where four robotic arms work like "steel craftsmen" — hammering, crushing, and magnetically sorting reinforcing bars from concrete. All of this is controlled remotely by workers in the green intelligent control center, who oversee operations as effortlessly as playing a video game.
After the primary process, concrete pieces reduced to under 50 centimeters move to the backend processing hub. There, they undergo three-stage crushing, rebar separation, and vibrating screening. A digital remote monitoring and control platform coordinates the entire operation, using variable frequency drives to achieve integrated "crushing and shaping" control and refined aggregate preparation. The system produces four grades of recycled aggregate: 0-5mm, 5-10mm, 10-20mm, and 20-30mm. Simultaneously, the enclosed negative-pressure dust removal system and waste powder recovery units silently capture every particle of dust, effectively minimizing the environmental impact of dust and noise on surrounding communities.
"This modern green concrete recycling line enables centralized, unmanned, and refined processing operations. It can process 1,800 to 2,000 tons of discarded components daily — nearly 60,000 tons per month — producing approximately 57,000 tons of recycled aggregate. This approach not only enhances the intrinsic safety of crushing operations and raises the level of intelligent management, but also reliably secures the sand and gravel supplies needed for construction," explained Yang Lei, chief engineer of the road surface section for Poly Changda Engineering Co.'s Guangzhou-Shenzhen Expressway renovation project (Sui-Guan segment).
The project is committed to high-value application principles. By optimizing blending ratios, recycled aggregates are now widely used in concrete pavements, precast components, and other applications. Plans are underway to extend their use further into load-bearing bridge structures and other concrete engineering applications. Fine powder recovered during production is repurposed into recycled micro-powder foam concrete, partially replacing cement as a cementitious material. This approach ensures every category of recycled material is utilized to its full potential.
The Guangzhou-Shenzhen Expressway renovation project is among the first batch of major infrastructure initiatives under the Ministry of Transport's "14th Five-Year Plan" for accelerating the building of a strong transportation nation. It also stands as a key provincial construction project for Guangdong. Upon completion, the upgraded expressway will play a pivotal role in driving the deep development of the Greater Bay Area, building a modern transportation system, and advancing the region's and the nation's transportation development goals.