BETCRETE 3.0 - Alternative binders: development, verification and application

This report provides an overview of the development, verification, and potential application of alternative binders for concrete within the BETCRETE 3.0 framework. A range of natural and industrial by-products have been investigated, focusing on their ability to replace Portland cement clinker and reduce the environmental impact of concrete production. Heidelberg Materials Cement Sverige AB evaluated a volcanic pozzolan with high amorphous content. SCHWENK Sverige AB explored the use of a natural sedimentary pozzolan (Opoka) from Lithuania, characterized by high reactivity (high SiO2 content) and local availability. Strängbetong AB (Consolis) tested bio-ashes derived from rice husks. Ragn-Sells contributed with residual ash from waste processing (Ash2Salt), showing latent hydraulic or pozzolanic properties. Boliden AB investigated an industrial by-product from mining and metallurgical processes as potential low-carbon pozzolanic cement constituent. Swecem AB continued the implementation and testing of ground granulated blast furnace slag (GGBS). The findings demonstrate promising fresh and hardened concrete properties, satisfactory durability performance regarding chloride resistance and alkali-silica reaction (ASR) and highlight the need for careful curing when using pozzolanic materials. The work also identifies future challenges in ensuring material availability, standardization, and optimization for broader industrial adoption.

BETCRETE 3.0 – Concrete with certified fly ash for drinking water plant construction

BETCRETE has been conducted as a national collaborative project addressing the challenges and necessary actions to achieve the goals set out in the roadmaps for the Swedish cement and concrete industries. The project consortium consisted of organizations impacted by and contributing to these roadmaps, representing key actors across the entire value chain. Over time, BETCRETE has established itself as an independent and recognized platform for cross-disciplinary dialogue and for driving both regulatory and technical development of innovative solutions. It serves as a value-creating knowledge and information channel for cement and concrete-related issues.

The overall objective has been to reduce CO₂ emissions from concrete by mobilizing the entire value chain around climate efforts. This includes addressing joint collaboration challenges, legislative and financial barriers, and implementing short- and long-term technical solutions using new materials and technologies. A crucial condition has been the coordination of roadmap efforts between the cement and concrete sectors, as well as the removal of obstacles to their implementation. The project also aimed to contribute to the development of cross-industry KPIs and strengthen the sector’s ability to measure, track, and communicate its sustainable transition.

As part of the BETCRETE project, the potential use of climate-improved concrete with fly ash was evaluated for drinking water infrastructure. Laboratory and field tests were conducted at two Swedish water treatment facilities to assess whether partial replacement of Portland clinker with CE-marked fly ash affects drinking water quality. Initial measurements showed slightly elevated levels of certain elements, but all remained within regulatory limits. Concentrations decreased over time and with increased water turnover, indicating a self-stabilizing effect. The results support the safe and continued use of fly ash-based concrete in contact with drinking water, enabling more sustainable construction practices.

The BETCRETE 3.0 work package focused on Sustainability indicators has demonstrated that it is possible to collect and analyze key sustainability data from the concrete industry, and that the industry is moving in the right direction toward reducing its climate impact. The main reduction in average GWP (Global Warming Potential) per cubic meter of concrete has so far mainly been achieved through the increased use of alternative binders, supported by updated standards and improved cement types. However, further progress is constrained by factors such as stricter technical requirements, availability of alternative materials, slow implementation of updated regulations, and inconsistent climate-related demands in procurement processes.

To achieve long-term national roadmap goals, there is a clear need to establish a national database of sustainability indicators for the concrete sector, extend data collection over time, and develop new indicators that reflect different construction segments and industry changes. Future developments in low-carbon binders must also be integrated into sustainability assessments. Additionally, data systems must be developed to enable efficient digital data transfer and be accessible for small and medium-sized enterprises.

BETCRETE 3.0 has laid a solid foundation for future work. However, realizing the full potential of climate-improved concrete will require coordinated efforts in policy, innovation, standardization, and data infrastructure.

This RISE report is a short version of SVU report 2022:5 “Klimatförbättrad betong för dricksvattenanläggningar” (Low carbon concrete for drinking water infrastructure). The purpose of the project was to clarify if the carbon footprint of concrete for drinking water infrastructure can be lowered by replacing Portland cement with supplementary cementitious materials (SCM) accepted for use in concrete without influencing the quality of the drinking water negatively with regard to trace substances and PAH. In addition to reviewing the literature, leaching tests and LCA analyses were conducted on thirteen concretes mixes with varying binder compositions. The results show that it is possible to replace up to 50 % of the cement with the SCMs, ground granulated blast furnace slag (GGBS), silica fume and fly ash. All this may be GGBS and up to 35 % fly ash may be used. This is valid under condition that a drinking water facility which in its entirety is new drinking goes through a tuning period of some days up to a week during which the water quality is monitored before water is delivered to clients. Leaching of some substances is somewhat increased and others are decreased by the replacement of the cement, however the changes are so small that the content in the drinking water in a real facility is only marginally influenced. Which type of binder to use should be decided based on other these materials influence on other concrete properties, for instance on the strength development. The decrease of the carbon footprint is roughly proportional to the cement replacement ratio.

This report describes work performed by RISE within Återhus project funded by the Swedish Innovation Agency Vinnova within Challenges-Driven Innovation program. The project aimed for developing new tools for accelerating the transition to circular construction understood as reusing building parts in new buildings. The key part of that process was identified as quality assurance and tackling the challenges concerning legal regulations, certification processes, determination of material quality by non-destructive and destructive testing, as well as calculation of remaining service-life. The report discussed also the most common deterioration mechanisms affecting service-life based on the pilot cases from the project. The calculation tool included carbonation and chloride ingress as two main mechanisms leading to risk of corrosion. Additionally theoretical relation of environment relative humidity to corrosion rate was embedded in the calculation to give an estimate of the remaining propagation period after corrosion initiation. The calculation tools were applied to estimate the residual service-life of slab elements of four pilot buildings based on empirical data gathered during inventory and condition assessment using both non-destructive methods and laboratory testing. A simple classification of concrete elements was proposed with a clear link to three main factors: remaining calculated service-life, observed cracking and the target environment.

This paper investigates the fracture mechanical properties of concrete, using crushed concrete aggregates (CCA) and granulated blast furnace slag (GGBS) for partial cement replacement. CCAs made from prefabricated concrete replace 100% of the fine and coarse fractions in concrete recipes with w/c ratios of 0.42 and 0.48. Two pre-treatment methods, mechanical pre-processing (MPCCA) and accelerated carbonation (CO2CCA), are investigated for quality improvements in CCA. The resulting aggregates show an increased density, contributing to an increase in the concrete’s compressive strength. The novelty of this paper is the superposition of the effects of the composite parts of concrete, the aggregate and the cement mortar, and their contributions to concrete fracture. Investigations are directed toward the influence of fine aggregates on mortar samples and the influence of the combination of coarse and fine aggregates on concrete samples. The physical and mechanical properties of the aggregates are correlated with mortar and concrete fracture properties. The results show that CCA concrete achieves 70% of the fracture energy values of concrete containing natural aggregates, and this value increases to 80% for GGBS mixes. At lower w/c ratios, MPCCA and CO2CCA concretes show similar fracture energies. CO2CCA fine aggregates are the most effective at strengthening the mortar phase, showing ductile concrete behavior at a w/c ratio of 0.48. MPCCA aggregates contribute to higher compressive strengths for w/c ratios of 0.42 and 0.48. Thus, mechanical pre-processing can be improved to produce CCA, which contributes to more ductile concrete behavior.

Strategic reuse of demounted concrete elements in new buildings may be one of the solutions that will support the transition to circular construction. To ensure wider application of concrete reuse, RISE developed a methodology for the assessment of the structural condition of existing buildings, and the selection of elements suitable for reuse, including guidelines for their disassembly, storage, and installation. However, one of the main obstacles for wide application of concrete reuse is the uncertainty concerning the remaining service-life of concrete elements and evaluation of quality over the future service-life in a new building. This paper describes a methodology for material and structural assessments which combine non-destructive, on-site testing with traditional laboratory tests of samples extracted from the structures. The results are intended to support the decision-making process on reuse and give a technical basis for the design of new buildings. Great consideration is put on various deterioration mechanisms for concrete and steel corrosion affecting structural condition of housing and office buildings. To assess the impact of degradation processes, theoretical models are considered, while the remaining service life is estimated by means of a simplified approach that provides the basis for evaluation of likelihood and severity of consequences entailed by material degradation on the structural performance. The proposed approach was validated on the results from three pilot projects, where real buildings in Stockholm and Uppsala, Sweden, were reused or prepared for reuse to different extent. The analysed buildings had different functions (housing, office, parking) and structures (prefabricated elements and in-situ casted concrete), being representative for Swedish building stock. One of the buildings has been already dissembled and the prefabricated, where prestressed hollow-core slabs have been successfully reused for a new office building construction. Based on these experiences, a simple classification system for quality of concrete elements for reuse was proposed with three main parameters, namely calculation of remaining service-life, extent of cracking and the target exposure class. The proposed system is not complete and must be further validated for various types of elements and structures by wider group of market actors.

Further development of a test method for anti-graffiti products for concrete surfaces Modified test methods for the performance of anti-graffiti coatings are presented in this report. As a base a test method applied in Sweden since is used which involves outdoor exposure of concrete slabs on which the coatings are applied followed by application of the graffiti and cleaning. The modifications are based on a review of methods existing in other countries, discussions with producers of anti-graffiti coatings and a test program carried out at RISE in Borås. The tests were carried out with two sacrificial coatings and some permanent coatings. In the latter case the graffiti is applied and cleaned ten times. In the existing method, the outdoor exposure is said to be three months. However, it was found that when this exposure takes place, in winter or in summer, greatly influenced the protective capability of the coating. In this project the influence of three different exposures were investigated; three month summer exposure, three month winter exposure and twelve month exposure. The test showed that the three-month summer exposure and the twelve-month exposure gave comparable results. Hence prolonging the exposure period is not necessary. However, very deviating results were obtained after the three-month winter exposure. The evaluation of the protective capability is started with a visual inspection against certain specified assessment criteria on remaining stains and visible marks of graffiti. If the coating met the assessment criteria for the visual inspection, assessment criteria on colour changes measured with a colour measuring device shall also be met. Separate assessment criteria for measured colour changes are used for sacrificial and for permanent anti-graffiti coatings. For a sacrificial coating, the assessment criterium is given in relation to the original concrete surface, while for a permanent coating the assessment criterium is formulated in relation to the exposed surface. It was found that the performance requirement on changes in gloss was irrelevant. In the revised method the selection of colour types and water temperature and pressure used in pressure washing has been modified to be consistent with praxis. The drying between cycles including application of graffiti and cleaning was shortened. The method is divided into two methods; one for sacrificial anti-graffiti coatings and one for permanent anti-graffiti coatings that does not require the use of chemical compounds. The latter method is not applicable to permanent anti-graffiti coatings which need the help of chemical products to give satisfactory cleaning.

Rapporten beskriver i en enkel form karbonatisering som kemisk fenomen. Var kommer koldioxiden från, hur tas den upp igen av betongen och hur skall den beaktas i en LCA. I tillägg till detta har en fallstudie genomförts där koldioxidupptaget i ett flerbostadshus beräknats för olika scenarier där designlösningar valts för att maximera koldioxidupptaget och därmed även sänka koldioxidavtrycket för hela byggnaden. Arbetet har genomförts inom ramen för BETCRETE 2.0 som samfinansierats av Vinnova inom programmet utmaningsdriven innovation (UDI) och deltagande företag. Författarna till denna rapport representerar Cementa AB (Anders Selander och Stefan Sandelin), Thomas Concrete Group AB (Carlos Gil Berrocal och Ingemar Löfgren) samt RISE (Katarina Malaga). Fallstudien som presenteras i Bilaga 2 är skriven av Carlos Gil Berrocal.

Rapporten presenterar resultat från projektet ‘Kartläggning av befintlig provnings-verksamhet för cement och betong i Sverige och bedömning av provningsbehov vid introduktion av nya cement’. Mot bakgrund av en minskad eller stoppad produktion av cement vid Cementas fabrik i Slite gav Regeringen Verket för innovationssystem (VINNOVA) den 3 november 2021 i uppdrag att kartlägga befintlig provningsverksamhet för cement och betong (N2021/02773) som finns tillgänglig för svenska aktörer och att föreslå åtgärder som kan skapa förutsättningar för en samordning vid en kraftigt ökad efterfrågan på denna verksamhet. Denna rapport behandlar hur provningsbehovet kan komma att utvecklas vid stopp i den svenska cementproduktionen i Slite vilket resulterar i ett behov av introduktion av stora volymer av ett eller flera nya cement under kort tid. Denna händelse benämns i rapporten förenklat som “cementkris”. Rapporten pekar på några förutsättningar som bör gälla för att ett cementbyte skall kunna genomföras rimligt kontrollerat. I rapporten görs det inte någon bedömning av hur byggbranschen eller samhället i stort skulle påverkas av en cementkris. Det görs inte heller någon analys av vem som tillser att produktions-bortfallet från Slite ersätts med annat cement eller varifrån detta cement kan komma. För en bedömning av provningsbehovet av betong har detta inte någon avgörande betydelse. Ett nytt cement från Kina kräver för betongtillverkaren lika mycket provning som ett nytt cement från närområdet i Europa eller för den delen Sverige. Förutsatt att cementet i sig är CE-märkt och uppfyller svenska krav.

Den huvudsakliga slutsatsen är att: Under förutsättning att inte avkall får göras på de krav som ställs på cement och betong i Sverige idag krävs det att nu använda och nya cement finns tillgängliga parallellt under en övergångsperiod på minst två och ett halvt år. Detta gäller främst betong till anläggningskonstruktioner och infrastrukturprojekt där kraven på kvalitetssäkring via provning på ackrediterade laboratorier är hög. På grund av ökat provningsbehov går det inte att genomföra ett omfattande byte av cement på ett stort antal betongfabriker under kort tid utan betydande störningar och stopp i betongleveranser till svenska byggarbetsplatser, om inte nu använda och nya cement finns tillgängliga parallellt. Inom husbyggnadsområdet är behoven av provning på ackrediterade laboratorier lägre. Hur snabbt och smidigt ett byte av cement kan göras för husbyggnadsbetong avgörs i stället av möjligheterna att utföra nödvändiga interna provningar och intrimningar på fabrikerna.

Om nu använda och nya cement till anläggningsbyggandet finns tillgängliga parallellt under minst två och ett halvt år är bedömningen att nödvändig ökning av provnings-kapacitet hinner byggas upp samtidigt som ett byte från nu använda till nya cement kan göras på ett rimligt kontrollerat sätt med avseende på behovet av extern provning. Detta förutsätter emellertid att samtliga nya cement är CE-märkta och uppfyller svenska krav samt en samordning av provningskapaciteten inom vissa kritiska provnings-områden. För att öka provningskapaciteten på nationell nivå inom kritiska provnings-områden krävs en noggrann planering av hur en sådan utökning skall genomföras (lokaler, utrustning, kompetens, vem som skall vara huvudman) och vem som skall bekosta en sådan ökning av provningskapaciteten.