01

Engineering waste slurry has long been regarded as the waste most difficult to regenerate and utilize as a resource. It is characterized by high consistency, difficulty in natural dewatering, and easy spread of pollution; it can neither be discharged directly nor easily settle naturally. How to dispose of massive amounts of engineering slurry in a green and efficient manner has become a huge challenge. Traditional slurry disposal methods mostly adopt "harmless landfill," that is, dewatering and drying the slurry, pressing it into mud cakes, and then landfilling them. However, this solution has extremely high energy consumption costs and carries risks of environmental pollution.

      In response, Tunnel Engineering Co., Ltd. Urban Construction Materials proposed a new "turning slurry into gold" solution and independently developed a low-carbon soil hardening agent. Simply mixing and combining waste slurry with the soil hardening agent can convert the waste slurry into fluid solidified soil usable for engineering construction, serving as synchronous grouting material and backfill material required by projects.

As a new type of powdery hydraulic cementitious material that can replace cement, the low-carbon soil hardening agent developed by Tunnel Engineering Co., Ltd. Urban Construction Materials contains no cement clinker, and its preparation process requires no high-temperature calcination. It only needs to be fully mixed with waste slurry in a certain proportion to achieve "turning slurry into gold," and the prepared fluid solidified soil features good impermeability and stable performance.

02

The fluid solidified soil prepared by Tunnel Engineering Co., Ltd. Urban Construction Materials can seamlessly fill drainage pipe trenches, building roof slabs, underground spaces, and many other fields. Moreover, compared with traditional slurry disposal methods, the current resource conversion process is much simpler: waste slurry is first pretreated by equipment into standard slurry with qualified parameters, then combined with the soil hardening agent through precise metering, and finally prepared into fluid solidified soil through efficient mixing and stirring. The entire production process generates no other waste and avoids high-energy-consumption process steps such as slurry dewatering, truly achieving 100% resource-based and low-carbon utilization of waste slurry.

At present, Tunnel Engineering Co., Ltd. Urban Construction Materials has built mobile demonstration bases for resource-based cyclic disposal of engineering slurry at multiple shield tunnel construction sites in Shanghai. Each mobile slurry disposal point can handle 100 cubic meters of slurry per hour. The fluid solidified soil prepared from engineering waste slurry has been successively transported to more than 20 projects, including the Phase I project of Line 21, serving major engineering construction.

03

The resource-based utilization of construction waste likewise needs to follow the principles of classified disposal and making the best use of everything. Just like community waste sorting, which is divided into dry waste, wet waste, and hazardous waste, construction waste is also divided into engineering slurry, engineering residue soil, decoration waste, and so on. Different types of waste all have a path to rebirth that matches their characteristics.

For example, in river dredging and ecological treatment projects, large amounts of contaminated sediment are generated. Tunnel Engineering Co., Ltd. Urban Construction Design Group and Urban Environment convert the sediment into safe planting soil through dewatering and microbial treatment, realizing harmless cyclic utilization of polluted waste.

Another example is the discarded "dry waste" in projects—waste concrete. Tunnel Engineering Co., Ltd. Urban Construction Materials recycles, crushes, and screens it into recycled aggregate, which is then formulated into recycled concrete. This green building material has been successfully applied in various scenarios such as housing construction and foundation cushion layers.

As for waste asphalt, plastics, and rubber materials generated by transportation projects, Tunnel Engineering Co., Ltd. Shanghai Road & Bridge can, through advanced processes, convert them into modified asphalt mixtures with excellent performance, realizing closed-loop utilization of waste materials in the transportation field.

It is precisely through refined "classified" treatment based on the categories of construction waste, combined with targeted technological innovation, that Tunnel Engineering Co., Ltd. has found an efficient and environmentally friendly resource utilization path for every major type of construction waste, contributing important industrial practice and technical support to Shanghai's comprehensive advancement of "zero-waste city" construction.