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CONSTRUCTION EFFICIENCY AND LAND USE
Climate emissions cut to a minimum in industrial construction building Careful planning and scheduling made it possible to use the dredging spoils from sea routes and industrial by-products in the construction of an industrial area in Rauma. Text Tarja Sinervo P H OTO : R A JA L A P R O S H O P
Tuomas Suikkanen Project Manager, Ramboll
In the development of the Sampaanalanlahti bay area, part of the old bay will be transformed into an industrial storage area. The Circwaste subproject, designed by Ramboll, provided many benefits by using dredging spoils dredged from maritime shipping lanes and by–products from a nearby industrial area in the construction of the area. – The goal is to save virgin aggregate, reduce climate emissions and costs compared to traditional civil engineering, says project manager Tuomas Suikkanen from Ramboll. Virgin aggregate is an unprocessed natural mineral that is a non–renewable or slowly renewable natural resource. Often it has to be transported to construction sites from afar, in Sampaanalanlahti it would have been gravel or sand from some sand quarry. Now, there was instead dredging material dredged from Rauma Southern Seaway that could be used as backfill. The bottom of the bay consisted of a thick layer of mud and clay. It was filled up to sea level with dredging spoils. The soil was then mass stabilized, i.e. the low quality areas were reinforced by mixing a binder in order for the soil to become sufficiently firm and stable for construction. With the help of mass stabilization, soft material could be left in place, thus avoiding large–scale mass exchange.
Industrial by–products instead of cement The project also investigated successfully the utilization of industrial by–products in stabilization instead of cement. According to Suikkanen, the highest CO2 emissions – up to more than 90 percent – of the stabilization techniques used as a bottom reinforce-
When working with waste, it is important to find out the suitability of waste materials for the project and to make sure that they are available at a sufficiently early stage. ment method in civil engineering come from the production of cement, traditionally used as a binder. But by using by–products such as fly ash from a nearby paper mill and biopower plant, the use of cement could be minimized. – We managed to cut climate emissions and save costs when land and stabilizers were obtained nearby, the dredging spoils did not need any new landfills and industrial waste did not have to be transported to a landfill, Suikkanen sums up. The use of recycled materials in construction is the sum of many components. – The utilization of alternative construction solutions and industrial waste must always be considered on a project–by–project basis. Recycled materials should be available within a reasonable transport distance and in a safe and environmentally friendly manner. The utilization of recycled materials is also studied in the Finnish Transport Infrastructure Agency’s sub–project on road projects. In the project, the challenges and benefits are largely the same as in the Sampaanalanlahti project.
Other construction efficiency and land use subprojects of the Circwaste project: • Karelia is investigating the overall picture of plastic waste generation in the North Karelia region and is preparing a waste plastic recovery scenario. In addition, the project will update North Karelia’s regional waste management system and carry out legal and technical-economic studies on plastics processing. The project collects various plastics from agriculture and construction sites, and their suitability as raw materials for new products is being tested. The aim is to produce new business models related to the use of plastics that can be duplicated elsewhere in the future. Further information: Simo Paukkunen, Project Specialist, firstname.surname@karelia.fi • In the city of Pori, resource-efficient construction is promoted, and co-operation between construction industry actors related to the circular economy is being strengthened. The project organizes a cooperation network between builders, construction companies, property owners, authorities and universities. The network implements successful practices for recycling and reducing construction waste. In particular, the city supports the circular economy of building components and demolition waste through various practical measures. The construction sites selected for the project aim to achieve the required 70% recycling rate. Further information: Anu Tuovinen, Project Coordinator, City of Pori, firstname.surname @pori.fi • The waste management company Puhas Oy is developing the sorting of construction waste from its point of origin together with construction companies in the Joensuu, Ilomantsi, Kontiolahti, Liperi and Polvijärvi areas. The aim is to streamline the processes for the separation and recovery of waste materials in waste centers and to communicate effective practices to construction operators. Further information: Matti Mikkelä, Project Manager, Puhas Oy, firstname.surname@puhas.fi
