Concrete waste is utilized in Sweden mostly for backfilling in road applications and building landfills. The techniques for recycling concrete to replace natural aggregates are in place and makes it possible to produce circular and climate reduced concrete. This paper explores concrete crushed aggregates (CCA) from rest concrete, produced using industrial crushing methods. Also, the regulatory framework supporting recycling has been discussed. The Swedish concrete standard is implementing to a lower grade the use of CCA in new concrete in comparison to other European standards specially regarding the use of fine CCA fractions. Results for CCA water absorption and apparent density from lab scale and industrial crushing are shown. The CCA fulfills claims for aggregates for indoor concrete. With further improvements in the crushing process, CCA is fit for applications in outdoor concrete.

Concrete waste is underutilized in Sweden, being used for backfilling in road applications and constructing landfills. When it shows the potential for use in load-bearing applications, as an alternative to natural aggregates, to produce circular and climate reduced concrete. This paper explores concrete crushed aggregates (CCA) from reclaimed concrete, produced using industrial crushing methods. The regulatory framework supporting recycling has been discussed. The Swedish concrete standard is less adopting to the use of CCA in new concrete in comparison to other European standards specially regarding the use of fine CCA fractions. Results for CCA water absorption and apparent density from lab scale and industrial crushing are shown. The CCA fulfills claims for aggregates for indoor concrete, with improvements in the crushing process, CA can suit requirements for outdoor concrete. 

A recycling pathway using flat glass waste as a supplementary cementitious material (SCM) leads to circularity in concrete production through industrial symbiosis. By incorporating glass waste, the environmental impact of cement can be reduced, contributing to the goal of climate-neutral concrete by 2045. This review study highlights the pozzolanic, chemical and physical properties of glass powder (GP) activated through mechanical process. The relationship between the strength activity index and particle size of GP as well as the hydration phases and the mitigation effect of alkali-silica reactions (ASR) is discussed.

A recycling pathway using flat glass waste as a supplementary cementitious material (SCM) leads to circularity in concrete production through industrial symbiosis. By incorporating glass waste, the environmental impact of cement can be reduced, contributing to the goal of climate-neutral concrete by 2045. This review study highlights the pozzolanic, chemical and physical properties of glass powder (GP) activated through a mechanical process. The relationship between particle size of GP and the strength activity index as well as the hydration phases and its potential to reduce alkali-silica reactions (ASR) are discussed.

Cirkulärt klimatreducerat betongelement i nybyggnation är ett 2-årigt Vinnova projekt som kom till som ett led i utvecklingen av cirkulära fastigheter med avsikt att återvinna betong och fönsterglas samt återbruka prefabricerade betongelement från fabrik eller rivningsobjekt.

Projektet har varit ett samarbete mellan Högskolan i Borås som projektledare, fastighetsägarna Riksbyggen och kommunala bostadsbolaget Bostäder i Borås, Borås Stad, krossmaskintillverkaren Sandvik, ballastproducenten NCC Industri, fabriksbetongtillverkaren Sweock, prefabelement tillverkaren UBAB och konstruktionskonsulten Stiba.

Projektet har skapat fördjupad kunskap om återvinning och återanvändning av restmaterial och resulterar i följande ny teknik och innovationer för cirkulära materialflöden:

• en cirkulär ballast från betongrester har tagits fram på industriell skala med tillämpningsområdet ballast i ny betong; lämpligheten har visats med petrografisk testning, krossningsteknik, fysikaliska och frys och tö egenskaper har visats genom tester
• ett cirkulärt glaspulver från planglasavfall har tagits fram och används som cementersättning; bestämning av innehåll, malning och potentialen med glasersättning visas genom tester
• nya betongmix med cirkularitetsgrad upptill 90 vikt% har tagits fram med en klimatreduktion i nivå 3 från Svensk Betong
• transport och logistikinfrastruktur har optimerats för att säkra klimatfördelarna med cirkulära material.

Doktorander och postdoc samt forskare från Högskolan i Borås har varit delaktiga i projektet och publicerat vetenskapliga artiklar.

Studenter från Byggingenjörsprogrammet, Affärsutveckling Bygg och Fastighet samt Affärsingenjörsprogrammet Bygg vid Högskolan i Borås har deltagit i projektet och dokumenterat delar av resultaten genom sina examensarbeten.

Circular climate-reduced concrete elements in new buildings is a 2-year Vinnova project that was initiated as part of the development of circular properties with the intention of recycling concrete and window glass as well as reusing prefabricated concrete elements from factories or demolition sites. 

The project has been a collaboration between Borås University as the project leader, property owners Riksbyggen and the municipal housing company Bostäder i Borås, Borås City, crusher manufacturer Sandvik, aggregate producer NCC Industry, readymix concrete manufacturer Sweock, prefabricated element manufacturer UBAB, and structural consultant Stiba.

The project has created in-depth knowledge about recycling and reuse of rest materials and results in the following new technologies and innovations for circular material flows:

• a circular aggregate from concrete waste has been developed on an industrial scale with the application area of aggregate in new concrete; its suitability has been demonstrated through petrographic testing, crushing technology, and physical and freeze and thaw properties have been shown through tests
• a circular glass powder from flat glass waste has been developed and is used as a cement replacement; determination of content, milling, and the potential with glass replacement is demonstrated through tests
• new concrete mixes with a circularity degree of up to 90 weight% have been developed with a climate reduction of level 3 from Svensk Betong.
• transport and logistics infrastructure have been optimized to secure the climate benefits of circular materials.

Doctoral students and postdocs as well as researchers from the University of Borås have participated in the project and published scientific articles.

Students from the Building construction and technology program, Business Development in Construction and Real Estate, and the Business Engineering program in Construction at the University of Borås have participated in the project and documented parts of the results through their theses. 

Multidisciplinary approach is used to evaluate concrete with recycled concrete aggregates (RCA) from technical, environmental impacts and product circularity perspectives. Two RCA replacements investigated, RAC50: fine aggregates; RAC100: both coarse, fine aggregates. Reference, recycled concretes have same cement content, similar workability and compressive strength requirement, proven experimentally. RCA is sourced from pre-fab element discards of a Swedish plant, the logistical alternatives requiring environmental impact analysis. Alternatives are RCA crushing at plant and crushing at a different location including transportation. LCA shows transportation is second largest contributor after cement in all impact categories. RAC alternatives show lower total impact than reference concrete due to RCA replacement. A circularity index for concrete based on economic value of recirculated aggregates; supplements LCA for sustainability reporting. Circularity index results: RAC100 > RAC50 > RC. Combining circularity index with LCA helps optimize recycling process with regard to amount of recycled material and logistics respectively.

Objektsorienterad selektiv rivning för cirkulär ekonomi och minskad klimatpåverkan har varit  ett-årigt projekt som genomförts för att förbättra insamling av data och dokumentera rivning för delar av en byggnad där fastighetsägarna har för avsikt att återvinna/återbruk tegel, prefabricerade betongelement, platsgjuten betong samt fönsterglas. Projektet har varit ett samarbete mellan Högskolan i Borås, Riksbyggen, Bostäder i Borås och Borås Stad. Målet var att samla in data gällande rivningsteknik, logistik samt klimatpåverkan från objektsorienterade fastigheter som rivs och på samma ställe byggs nytt i stadsmiljö. Genom praktisk rivning av en tegelvägg, datainsamling för verifierad LCA och logistik har genomförts, cirkularitets- och klimatpotentialen för materialen uppskattats. Studenter från Byggingenjörsprogrammet vid Högskolan i Borås har deltagit i projektet och dokumenterat delar av resultaten genom sina examensarbeten. Denna rapport ger en översikt av metodologin, datainsamlings- och analysprocessen och grunden för ett säkrare beslutsunderlag för ägarna på objektsorienterade fastigheter.