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TECHNICAL PAPER

UsE of rEcyclED

concrEtE AggrEgAtEs

– fUll scAlE

DEMonstrAtIon cHRIsTIAn J. EngELsEn, JAcOB MEHus

Abstract million tonnes (Satpathy et al., 2016). Although there are large
uncertainties in the waste these calculations regarding both
Several successful demonstration projects have been conducted over and underestimation, there is no doubt that the Indian
in the past 20 years in order to verify the practical, technical C&D waste generation is enormous and is likely to increase
and environmental applicability of recycled aggregates. significantly.
One example is Sørumsand High School where 37% of
the natural coarse aggregates were replaced by recycled An Indo-Norwegian project has been initiated between Central
concrete aggregates. The project was well-planned with Public Works Department (CPWD) and SINTEF where the aim is
solid documentation of the recycled materials as well as the to increase the treatment and recycling capacity for construction
fresh and hardened concrete properties. The experiences and demolition wastes in India (Engelsen et al, 2017). The
obtained were that the project was competitive to the regular project will strive to implement international best practice,
project with natural aggregates with regard to costs, technical perform various capacity building activities and conduct pilot
performance, practical handling and environmental properties. demonstrations. It will focus on the production of recycled
Furthermore, recycled aggregates are included for use in aggregates from C&D waste with a documented stable quality
nearly all of the European (EN) aggregate standards, though applied in both bound and unbound user applications (e.g.
at varying implementation level. In India, a large deficiency of concrete production and road construction) (Engelsen
treatment and recycling capacity of C&D waste exists. Recycling et al., 2019). In connection to the capacity building activities,
by the wet process technology seems to increase, due to the CPWD delegations have visited Norway for training seminars
highly complex heterogenic waste received at the stationary and site visits. One of the sites visited was Sørumsand High
plants. Heterogeneity should be tackled by increased source School which was completed in 2003. Half of the concrete in
segregation, pre-mixing of feedstock materials and a daily the building is manufactured with recycled concrete aggregates
control of the recycled products. Homogenous feedstock source from construction waste. The project was implemented as a
of concrete waste is highly applicable to recycle into RCA. demonstration project in collaboration with Akershus county
authority. This paper presents all the results obtained in the
Keywords: Aggregates, Concrete, Construction, Demolition, demonstration project regarding RCA material characteristics,
Demonstration, Project, Recycled. fresh and hardened concrete properties and the practical
experience.
1. introDuCtion
2. DESCription of tHE DEMonStration
Construction and Demolition (C&D) waste is one of the
biggest waste streams in most countries. It contains wood, PRoJect
plastic and paper rejects, ceramics, mortar, concrete etc. The Sørumsand High School is approximately 13000 m and located
2
heavy inorganic part (from concrete and masonry) could be 30 km north of Oslo. It was built by Veidekke ASA on behalf
processed and refined into recycled aggregates. This type of of the building owner Akershus county authority (Mehus et
aggregates could substitute natural aggregates in a range al., 2003; Lahus et al., 2002). The RCA was produced by BA
of user applications like road construction, landscaping and Gjenvinning and the ready-mixed concrete was supplied by
concrete production. This will save natural resources, in many Unicon.
cases reduce the cost of transportation, minimize the waste
sent to landfills and even re-absorb CO 2 from the air through The decision to include the use of RCA at an early stage,
increased carbonation. In Europe, more than 500 million tons allowed recycled aggregates to be included as the main
are generated annually. For India the estimates of C&D waste alternative in the bidding documents for the contractor. The
generation vary from 25-30 million tons up to around 500 use of RCA in the new building has been conducted in close

30 The IndIan ConCreTe Journal | SepTember 2019