We aim to eliminate waste from construction operations by ensuring zero landfill disposal of waste during construction, by utilizing recycled materials, and by making buildings last longer.
Recycling and Effectively Using Resources at Construction Sites
The fundamental approach toward zero emissions at construction sites involves striving to reduce resource usage, curbing the amounts of waste that construction works generate, and promoting waste separation and recycling, thereby reducing waste destined for landfill disposal.
To reduce environmental impact, we carry out a wide range of resource-saving and efficiency initiatives, such as sending in materials without using packing supplies, using precast products to reduce on-site processing, and adopting construction methods that reduce the generation of temporary construction waste.
Kajima promotes on-site and inter-site reuse of construction surplus soil, and participates in the trial matching for effective public–private use program conducted by the Ministry of Land, Infrastructure, Transport and Tourism. In addition, we contribute to reducing waste and utilizing resources across the industry by sharing information and cooperating with other companies as a participating member of the construction byproduct commission of the Japan Federation of Construction Contractors.
Reducing Environmental Impact Across the Lifecycle
The use of construction materials and the generation of waste bring an impact to the environment at each stage of the building lifecycle, including new construction, renovation, and demolition. Kajima developed and uses a proprietary Life Cycle Assessment (LCA) system to make predictions about construction-related waste throughout the building lifecycle. By changing the materials that we use and the structural work methods employed in the design phase, selecting more appropriate waste disposal methods, and taking other similar measures, we strive to increase the recycling rate, reduce the final volume of landfill waste, and mitigate the environmental impact in the disposal process.
Higher Quality Recycling——Promoting the Use of Manufacturer Recycling
Kajima promotes the implementation of Manufacturer Recycling, a national permit system. In this system, the Minister of the Environment permits manufacturers to collect waste (such as offcuts) produced from their construction materials or other products, and appropriately process and recycle it. As it enables waste to be recycled back into the same product, this recycling system enables higher-quality recycling.
For example, drywall panels are collected from Kajima construction sites and separated into paper and gypsum powder at the manufacturer's factories. The paper is recycled into cardboard and other products, and the gypsum powder is recycled to be used as a raw material for drywall panels again. This method of recycling waste back into their original materials is known as horizontal recycling, and it is a key initiative for creating a resource-recycling society.
More Eco-Friendly Construction Materials——Developing Concrete that Uses Byproducts
Cement is a principal construction material, and is a major source of non-energy CO2 emissions.
To reduce the amount of cement used, Kajima is developing an eco-friendly type of concrete that contains a significantly high amount of blast-furnace slag, a byproduct of iron manufacturing. We are working toward mainstreaming this concrete, thereby contributing to recycling resources and reducing CO2 emissions.