Construction type: Civil Engineering

Concrete type: Structural concrete

Cement type: CEM III/C (90% GGBS +CEM I)

Sustainable features: The contract to supply an upgrade to the seafront in Dawlish, Devon, included a high-specification underwater concrete and a new lower carbon product. The low carbon mix solution demonstrates that even on the most complex projects there are opportunities to find carbon savings. In this case, 1400m³ of concrete saved over 250 tonnes of CO2 compared to the equivalent grade of conventional concrete.

The Great Western Main Line is the only line running to the South West of England.
It is a vital link for transport, tourism and freight movements. The collapse of the sea
wall in 2014 led to a £1.2bn impact to the South West economy. Innovative concrete mixes designed have helped to restore and protect a key rail route from storm wave damage and erosion.

Construction type: Road tunnel

Concrete type: Various ECOPact recipes, 30% - 33% lower carbon footprint compared to CEM I

Cement type: Holcim ECOPlanet Ekspert cement (norm type CEM II/B-M (S-V-LL) 42,5 N)

Sustainable features: Croatia’s landmark Istrian Y Motorway used Holcim ECOPact low-carbon concrete in the construction of a key tunnel, cutting its CO2 emissions by 30%. To drive circular construction, tunnel excavation material was used to produce the low-carbon concrete, saving over 200,000 tons of virgin aggregates.

For this crucial project, Bina Istra and Bouygues Construction partnered with Holcim to find an integrated solution that would lower the project’s carbon footprint, close the material loop and improve the tunnel’s drainage during times of heavy rainfall. To respond to the project’s strict performance, low-carbon and environmental demands, Holcim Croatia is supplying more than 120,000 cubic meters of ECOPact, the world’s broadest range of low-carbon concrete with CO2 reduction starting at 30% and no compromise in performance.

Link for more details: https://www.holcim.com/who-we-are/our-stories/ecopact-saves-co2-croatia-tunnel

Construction type: School

Concrete type: Mainly "classical" RMX concrete: C25/30/XC4/XW1/XD2/XF1/XA1L in the ground area (floor slab and cellar) and C25/30/XC2 for the rest, Pillars: C40/50/XC2

Cement type: During 2020-2021, CEM II/A-M (S-L) 42,5 N DER SCHWARZE + Fluamix C in a mixing ratio of 80:20. This results in a clinker factor of ~60% which corresponds to a CEM II/C.
(Note: In 2022/2023 the project replaced CEM II/A DER SCHWARZE by CEM II/B-M 42,5 N ECOPlanet SCHWARZ.)

Sustainable features: With low-carbon cement, Holcim contributed to sustainably building one of the most energy-efficient schools in Vienna, the Bildungscampus Seestadt. It is able to cover 90% of its own energy needs thanks to a geothermal energy process that is optimized by concrete’s thermal activation properties.

Bildungscampus Seestadt Aspern Nord, a school in Vienna’s Aspern neighborhood, is a pioneering project in energy-efficient architecture solutions and building services engineering. It employs a future-oriented energy concept, which was specially designed for the use of renewable energy and its storage in the building through component activation of concrete.

Links for more details:
https://www.holcim.com/who-we-are/our-stories/vienna-energy-efficient-school
https://video.holcim.com/energy-efficient-school-in-vienna

Construction type: Infrastructure. New underground line in the city of Milan

Concrete and cement type: Concrete made with low-carbon pozzolanic cement and half a million tons of excavation materials sourced onsite from the same project

Sustainable features: For this project, Holcim supplied concrete made with low-carbon pozzolanic cement and half a million tons of excavation materials sourced onsite from the same project. This combination saved the infrastructure at least 30% CO2 emissions while significantly reducing the amount of virgin aggregates needed. Once completed, the M4 (“blue”) line alone will be able to transport over 85 million people, avoid more than 60 million car journeys, and reduce CO2 emissions by up to 75,000 tons each year.

Over the first six years of this project, Holcim supplied approximately 400,000 m3 of structural and sustainable concrete made with pozzolanic cement. Pozzolanic cement offers a lower carbon footprint than Ordinary Portland Cement with no compromise on performance. By using this type of cement, currently part of Holcim’s ECOPact range, the M4 Metro line saved at least 30% of CO2 emissions. The construction process of the M4 line also aligns with the principles of the circular economy. Materials resulting from the excavation of the underground stations were used to replace the aggregates necessary for concrete production. Holcim recovered and reused about 500,000 tons from the excavation process.

Link for more details: https://www.holcim.com/who-we-are/our-stories/milan-metro-low-carbon-circular-concrete

Riviera Tower – Part 1

Construction type: Structural working piles (1000cm & 1500cm diameter) - 15km3

Concrete type: ECOPact C 35/45 XA2 31,5mm, S5, SF1

Cement type: ECOPlanet CEM IV/B (P) 32,5N SR (aprox. 6.000 ton)

Sustainable features: Low clinker cement (-40% vs CEM I) / Based on Greek natural pozzolan.

Riviera Tower – Part 2

Construction type: Raft foundation (One-shot Mass Concrete 3m width) - 7,5km3

Concrete type: ECOPact C 30/37 XA2 16mm, WATERPROOF, S5, SF1

Cement type: ECOPlanet CEM III/B 42,5N SR (aprox. 3.000 ton)

Sustainable features: Low clinker cement (-65% vs CEM I) / Low heat of hydration.

Holcim is providing ECOPact low-carbon concrete for the largest urban regeneration project in Europe: The Ellinikon, located outside of Athens, Greece. The Ellinikon is the largest privately-funded investment in Greek history. Designed by Foster + Partners, the urban development on the Athens Riviera will be three times the size of Monaco, spanning 6.2 million square meters. It is also a milestone of sustainability: the project is set to increase the amount of green space in the Athens metropolitan area by 44%, and will recycle the infrastructure of Athens’s abandoned international airport. The Ellinikon will include residential, office and retail buildings, as well as medical, educational, sports and cultural facilities, all of which will meet the highest sustainability standards.

Link for more details: https://www.holcim.com/who-we-are/our-stories/ellinikon

Construction type: Multifamily residential (220 units)

Concrete type: C25/30 S4

Cement type: CEM III/A 42,5 N

Sustainable features: Made with the world's first fully recycled concrete: custom solution developed by the Holcim Innovation Center in which all components—cement, aggregates and water—are made of recycled materials. More than 6,000 tons of natural resources saved

A 220-unit social housing complex called “Recygénie” is currently under construction outside Paris, France. Built in partnership with Seqens and using a custom concrete made with Holcim’s ECOCycle®technology, this is the first fully recycled concrete building in the world.

Link: https://www.holcim.com/who-we-are/our-stories/fully-recycled-concrete-building

Construction type: infrastructure – bridge

Cement type: CEM II/B-S 42,5 N, CEM III/B 32,5 N SR-LH, CEM III/A 42,5 N LH and CEM I 52,5R

Sustainable features: sustainable materials – cements with lower CO₂ emission

The Pelješac Bridge is one of the largest infrastructure projects in the past three decades in Croatia. The Bridge spans a total of 2.4 kilometers, and it is an integral part of Croatia's transport system, connecting the very south to the rest of the country; for decades, crossing between Croatia’s territories by land required crossing its border with Bosnia and Herzegovina. This project was co-financed by the EU development funds; therefore, it was imperative that its construction and maintenance match the EU’s low-carbon strategy.

CEMEX Croatia d.d. supplied 37.000 metric tons of cement for the construction of the Bridge. Four types of cement were used: CEM II/B-S 42,5 N, CEM III/B 32,5 N SR-LH, CEM III/A 42,5 N LH and CEM I 52,5R due to the need for various types of concrete for different segments of the bridge. Usage of different types of cements highlighted their specific characteristics that alleviate implementation.

95% of all the cement used in the project belongs to CEMEX’s Vertua family of lower carbon products; cements with lower CO₂ footprint when compared to an industry reference* providing a more sustainable solution.

Thanks to using Vertua cements 8.471 tons of CO₂ were saved.

*Reference value Cement (CEM I with 95% cement clinker content): 822 kg CO₂ /t cement.

Construction type: Civil Engineering/Energy Works & Water Works/Hydroelectric Power Plant (HPP)

Concrete type: Reduced cement content/ Very low heat pozzolanic cement

Cement type: LH IV/B–(V) 22,5  (aprox. 175.000 ton)+ CEM II/B-(V) 42,5N (aprox. 78.000 ton)

Sustainable features: Low clinker incorporation cement (aprox. 52%)/ 1,2 Mton CO₂ emission per annum avoided

The 1158MW Tâmega Iberdrola facility is located in the Tâmega River (a right bank tributary of the Douro River) includes three dams and power stations: Gouvães, Daivões and Alto Tâmega. This will increase by 6% the Portuguese power availability. It will produce 1766 GWh per year thus avoiding simultaneously 1,2 million ton of CO₂.

Gouvães is a reversible generation and storage facility connected to the Daivões reservoir through a 7,6 km long head race and a nominal hydraulic head of 657m. It´s storage capacity is 20 GWh which is enough to provide continuous supply of electrical power to the metropolitan area of Oporto (over 1,7 M people) in a 24h period or the equivalent of all the China population mobile phones. It acts as backup and support for other renewable energy sources namely wind and solar. 40 000 m³ of concrete were placed.

Daivões is also a reversible generation (880 MW) and storage facility, 77,5 m high with a 64,5 m hydraulic head. 240 000 m³ of concrete were placed.

Alto Tâmega is a generation (160 MW) facility 106,5 m high and with a 87m hydraulic head. 222 000 m³ of concrete were placed.

Additional €1 500 million will be allocated to solar and wind projects currently under development in the region.

Construction type: Civil Engineering/ Energy Works solar panels plants

Concrete type: Precast concrete

Cement type: CEM II/A-L 42,5 R

Sustainable features: Extended life-time of solar panel supports/ Low maintenance

Solar energy is one of the most common clean energies and all the elements related must be sustainably designed in order to minimize all environmental impacts. In order to reduce environmental impacts caused by the transport of the steel used to produce the usual supports as well as the ones arising from corrosion protection, a concrete solution was developed by PRESDOURO: a three piece interlocking set based on two of the most well-known features of concrete: stability and lack of maintenance.

The system can provide adequate support and allows adjustment from 5 to 30 degrees according to the land slope and latitude of the solar park.

Construction type: office building transformation

Cement type: unknown

Sustainable features: concrete structure reuse

CONIX RDBM Architects transformed a modernist tower, built in 1969, located in the heart of Brussels. They converted the building from a solely office-centric structure to a versatile facility with public value. Despite the building being outdated and its facade being unadapted, the architects stripped the building to its concrete core, which proved perfectly reusable for its new purpose. The MULTI project, as it's now known, was selected as one of the laureates for Be.Exemplary 2017 for repurposing an emblematic, contemporary office building, thus linking public space with an accessible city platform. As ambitious urban development increasingly relies on large-scale reuse of buildings both now and in the future, adaptability of structures becomes paramount. Concrete, in this context, has proven to be an ideal construction material to meet these aspirations.

Photo © Jasper Van der Linden

Construction type: public building

Cement type: not known

Sustainable features: concrete core activation

The use of concrete core activation optimises the thermal capacity of concrete. Within the heart of the concrete slabs are water pipes connected to a geothermal field. This field either heats the water in the pipes (via a heat pump) or cools it passively. As a result, the activation of the concrete core ensures comfortable temperatures in all seasons in an energy-efficient and sustainable way. In the case of the Provinciehuis, floor convectors and ventilation nozzles were added locally to regulate certain zones. The Provinciehuis meets the passive standard due to efficient heating and passive cooling, optimal use of natural light, and the production of green electricity through solar panels, among other measures. As a result, the carbon footprint of the new Provinciehuis was estimated to be 162 tonnes of CO₂ in 2019, a significant reduction compared to over nine times that amount for the old Provinciehuis in 2010.

Photo © Provinciehuis

Construction type: Civil engineering/energy works & water works

Concrete type: Mass concrete

Cement type: CEM II/B-S 42,5N WT33

Sustainable features: Renewable energy ; improved overall ecology & biodiversity

The hydropower plant ‘Sohlstufe Lehen’ is located near the historical city centre of Salzburg. Due to this exposed location, particular attention was paid to the architecture and to an appropriate concept for open space.

Due to the confined space, the power plant had to be built in two construction phases with simultaneous re-routing of the River Salzach. Extremely complex special civil engineering works were necessary in order to create the conditions for excavation of the weir sections and the power house. A special type of concrete – SSK hydropower concrete – was used for the  foundations to resist the enormous water pressure.

The power plant was built to replace an existing low weir in order to restore the ecological patency of the River Salzach for fish, with the installation of a fish ladder as well as a newly created bypass channel. At the same time, it was possible to improve the flood protection and the groundwater management.

With the realisation of this unique construction project it has been possible not only to achieve the primary purpose of power generation – renewable hydropower for 23,000 households – but also to improve the overall ecology and urban design.

After completion of construction works in 2013 the power plant was awarded the European Concrete Prize 2014 in the category of ‘Civil Engineering’.

Photo © Rainer Iglar (waterfront view)

Construction type: Non-residential building/transport rail/railway station
Concrete type: Self-compacting concrete
Cement type: CEM III/B
Sustainable features: Concrete chosen for its durability under intensive use of public space

Train station in red fair-faced self-compacting concrete

The new train station in Herstal, Belgium has become the new landmark of the city. Now connecting the city to previously disconnected areas, the high tower of the station ensures visibility and grows into an emblematic symbol for the town. Beyond the strength of the architectural shape itself, the concrete building has a solid red colour. For its flexibility and in order to fulfil the structural and aesthetic requirements of the tower, ready-mixed concrete was the chosen material. In addition, the self-compacting properties of the concrete has given higher insurance of meeting the requirements for the aesthetic aspects of the surface. Laboratory tests, in cooperation with all actors (prescriber and the concrete manufacturer), led to precise specifications of the concrete, including the use of CEM III/B cement.

Credit: MULTIPLE architecture & urbanism

Photo: Filip Dujardin

Construction type: Residential building: Sustainable and environmentally friendly concrete in normal building construction

Cement type: CEM II/B-M (S-LL) 42,5

Sustainable features: Low carbon concrete

Housing development As Oy Vinssi in Helsinki was built in 2016 by SRV Construction Ltd. The target was to produce a concrete that has low environmental impact but still abides by normal building standards. The supporting slabs were cast with “Green Concrete” which was introduced by Rudus Oy in 2010. The sustainability target was accomplished by using CEM II/B-M (S-LL) 42,5 N cement and Class A fly ash.

The concreted structure was a supporting slab structure totalling 300 m3. The final strength of concrete was 45 N/mm3. Benefits achieved were lower carbon emissions while requirements for pumping, strength properties, exposure classes and a tight building schedule were fulfilled.

Construction type: Residential Building/Housing development

Cement type: CEM II

Sustainable features: Raw material saving using recycled concrete aggregates

The Florestine in Bordeaux is a social-housing building of almost 5000 m2. It is a collaboration between the local authority’s social housing office, architecture firm Moon Safari and Quarnot Computing, the firm behind the heat recovery from its smart home system servers that furnishes free heating. The 49 lodgings are environmentally friendly designed: each lodging benefits from a double solar orientation, a loggia or balcony and an open corridor with vegetable planters and rainwater irrigation. The low carbon design is fully supported by using recycled concrete at strategic points, such as the reservoir roof with rainwater recovery tanks. Using recycled aggregates from the residual concrete of concrete-mixers lowers the overall carbon footprint, while providing the same esthetical and technical qualities as traditional concrete, with identical production and placing characteristics.

Photo: Emile Counord

Contracting authority: Gironde Habitat, Architects: Moon Safari, General contracting engineering: Verdi, Environmental engineering: Less is more, Acoustics: Viam, Landscape: Gastel 

Construction type: Non-residential/Office Building with restaurant, kindergarten, reserve control centre

Cement type: CEM III/A 42,5 N, CEM II/A-LL 42,5 N, CEM III/B 32,5 N-LH

Sustainability feature: High Sustainability Rating

50 Hertz operates the transmission grid in northern and eastern Germany and provides the electricity for around 18 million people. The company’s new headquarters is situated in Berlin’s city centre. The building, constructed according to ecological and sustainable methods, has 13 aboveground floors and one underground floor. Its floor space totals approximately 24,000 m². Graz-based architectural firm, Love Architecture and Urbanism, won the architectural competition. 650 employees work in the building. The company`s reserve control center, a kindergarten, a restaurant and an underground parking garage are also included in the new head office. The building was rated Diamond, the highest rating, in the German Sustainable Building Council (DGNB) for its environmental, economic, sociocultural and functional qualities. The certification includes factors too, which are important during the construction: technology, planning, and design building process.

The architectonical concept overlays four bearing structures:

• Horizontal concrete floors, 35cm thick, with concrete C35/45. The floors are thermally activated for cooling and heating.
• External, meshed structure of composite columns, 42 cm thick, with concrete C35/45.
• Internal slim columns with concrete C50/60.
• Cores for staircases and elevators with concrete C30/37.

The waterproof basement and the foundations are made with concrete C30/37.

Clinker-efficient cements were selected depending on the demands of the structural components and the necessary properties of fresh and hardened concrete.

Construction type: Non-Residential/research centre

Concrete type: Mass concrete for radioprotection

Cement type: CEM II/B-S 42,5 N, CEM III/A 32,5 R-MSR, CEM III/B 32,5 N LH/SR

Sustainable features: Slag additions in mass concrete lower heat development & avoid cracking

The construction begun in 2014 and finished at the end of 2015, with an overall cost of more than €200 million. The total net building area is 24,46 2m² and the maximum building height 20 m. The aim was the examination of the light source which provides the ultra-short pulses, particularly the coherent extreme ultraviolet, X-rays and attosecond pulses.

The investor was the ELI-HU and the general contractor was STRABAG-MML and Swietelsky Hungary. The provider of the approximate 45,656 m³ concrete was Frissbeton, and for the special requirements of the research technology and serving the necessary functions of the facility they used 3 different types of Lafarge cement. For the construction, 75% low carbon cement was used.

The laser research centre’s main building area is approximate 6,642m² and in it special bunkers were built with the house-in-the-house technology. These special bunkers had to be built with special radioprotection. 1 and 2 metre thick reinforced concrete walls were used. For the special requirements of the bunkers, they used CEM III/B 32,5 N LH/SR cement, which was a perfect choice because it’s sulphate resistant blast furnace content, 32,5 MPA standard strength and low heat of hydration.

To provide stability for the buildings, according to soil mechanics, 819 piles were drilled under ground level. During the construction of the piles they used CEM III/A 32,5 R-MSR cement, which can be used to build monolithic structures exposed to aggressive chemical effects reaching the maximum limit of exposure classification XA2. The deepest piles are 45 meters below ground with a diameter of 1.8 m each and a special so-called bentonite-coated technology was used for the first time in Europe.

The most relevant requirement of the laser research centre was the vibration-free base (5500m²) to ensure laser stability. The CEM II/B-S 42,5 N cement was the most suitable for structural construction, which had a high post-strengthening and very low heat evolution due to the blast furnace slag content. The appropriate concrete mixture made with this type of cement has a very low chance of cracking due to its attributes.

Construction type: Non-residential building/Public building

Concrete type: Self-compacting concrete

Cement type: CEM II/A-L

Sustainable features: Historic building reuse & extension

This project involved the conservation of parts of the original Courthouse building dating back to 1849 and the construction of a significant extension to the rear which expanded the floor area by 200%. The completed project accommodates 6 separate courtrooms and all the necessary ancillary administration and support spaces. Concrete was chosen for the main structural elements as well as for thermal efficiency of the building.

A range of concrete mixes were required, including pump mixes with and without fibre reinforcement. CEM II/A-L was used as the primary cement throughout to provide flexibility while allowing the designers to address the requirement to deliver a low carbon building. The construction of circular columns where a self-compacting concrete mix was required was achieved using CEM II/ A-L with Type II additions an option which is permitted in the Irish National Annex to EN 206.

Design Architects – Office of Public Works; Executive Architects - Wejchert Architects; Main Contractor - BAM

Photo credit: PM Photography

Construction type: Residential & non-residential/office building

Concrete type: Recycled materials’ use

Cement type: Pozzolanic cement with low clinker content/reduced CO2 footprint

Sustainable features: High Sustainability Ratings

The Porta Nuova project is an urban renewal plan carried out in Milan. In an area of 290,000 m2, the project includes residential buildings, shopping areas, offices, and cultural venues. A continuous pedestrian area with green areas, squares, bridges, and a large park connects three different neighborhoods efficiently and safely.

Porta Nuova has obtained a gold certification according to the LEED environmental sustainability protocol promoted by the US Green Building Council. The overall sustainability strategy addresses six main issues: location, materials, water, energy, air and environmental quality.

Important results were achieved when compared to a traditional reference building: use of locally sourced construction products (41%), with significant quantities of recycled materials (20.5%) and high recycling of construction site waste (93%); reduction in the use of drinking water (-37.3%); energy savings (-22.5%); advanced technologies for external air filtration and monitoring systems for building operation, which ensure an optimal level of air quality and thermal comfort (emissions reduced by 42.86%).

Construction type: Civil engineering/transport road/bicycle path – width: 2 m; length: 9,5 km (19.000 m2)

Cement type: CEM II 42,5 B-V

Sustainable features: Raw material saving reusing old pavement

White topping

Principle of white topping: a thin(ner) concrete overlay also using the old pavement as a base layer.
White topping is an innovated solution, especially when combined with synthetic fibers.

Project Barneveld

The bicycle paths on both sides of the Apeldoornsestraat between Voorthuizen and Garderen needed to be reconstructed. The old asphalt pavement was deteriorated (cracks) and damaged by tree roots. Instead of totally removing the old asphalt construction, only about 8 cm was milled off.
On top of this, 12 cm of synthetic fiber reinforced concrete was placed with a paver. Normal thickness of a bicycle path in these circumstances would be 20 cm.

Savings on CO2 due to:

• using part of existing pavement
• removing less old pavement: saving on energy to remove and transport (and depot costs)
• less use of new concrete: 12 cm instead of 20 cm; less materials, mixing and transport of concrete

Savings on costs:

According to principal: 25% savings on costs compared to fully removing old asphalt layers and installing a new concrete path of 20 cm thickness.

Construction type: Non-residential building/Office building

Cement type: CEM II/A-V

Sustainable features: Energy positive building

Powerhouse Brattørkaia is an ambitious project with the aim of constructing the world`s northernmost energy positive building – a building capable of producing more renewable energy during its lifetime (60 years) than it consumes, including during its construction, use and demolition. The location is situated in the harbor of the city of Trondheim, at 63 degrees north – hence a cold climate. The design of the structure is focused on reducing the embedded energy for all components, but also create good and well-functioning office spaces. The embedded energy from materials is calculated to be almost 50% of the total energy in the project. The concrete accounts for 12% of the embedded energy of the construction. 

The energy production comes from solar panels on the roof, which is angled due to the northern location.

The building is constructed with a structural system of concrete, and post tensioned concrete slabs. These require concrete of class B35M90. Due to the forces involved with post tensioning, it was necessary that the concrete developed 25 MPa compressive stress capacity within three days of curing. Additionally, it was desired that the concrete had no more associated energy consumption than 1500 MJ/m3. 

A specific concrete recipe was developed for the project, with binder consisting of 50% fly ash, 10% silica fume and 40% cement clinker. The w/b-ratio was 0.4 and matrix volume of 290 l/m3 developed the required capacity within three days. This composition is sensitive to changes in temperature. Therefore, several measures were introduced to handle casting during winter and on cold days. Among these was use of accelerating admixture. This enabled workers to cover the fresh concrete at an earlier stage, and keep the concrete warm. 

Construction type: Non-residential building/cruise terminal building

Cement type: CEM II/A-L 52,5N (white cement)

Sustainable features: Lightweight aggregates (cork) & thermal insulation characteristics

The new cruise terminal opened in Lisbon in November 2017 is one of the biggest infrastructure projects in Portugal in recent years. The transfer of the cruise terminal of Alcântara to Santa Apolónia resulted in a new terminal which involved a total investment of over 70 million euros, 54 million of which was from the Administration of the Port of Lisbon (APL), and 23 million as a result of the concession contract for the construction, financing, operation and transfer, for a period of 35 years, with the Lisbon Cruise Terminals, an investment that aims to put Lisbon in "first league of major cruise ports in the world”.

The new terminal of Lisbon has a capacity of 800,000 passengers per year. By day, the landing and embarkation maximum is 4,500 people. There is also parking for 360 cars and 80 buses or cabs. Tourists can enjoy a panoramic terrace and free WiFi. The project was designed by Portuguese architect Carrilho da Graça.

Structural light concrete was used in the construction, with aggregates of cork in the North and South facades of the building. The use of this type of material held, initially, with the need for use of structural lightweight concrete to ensure the reduction of the weight of the structure, ensuring the necessary level of resistance to meet the structural requirements and architectural features. On the other hand, the use of cork granules as lightweight aggregate allowed for a substantially lighter concrete with improved thermal insulation characteristics, while making it a more ecological and sustainable solution resulting from the use of a recycled natural material.

The cement selected was the white Portland cement CEM II/A-L 52, 5N (br) since it's a high whiteness and mechanical resistance which allows pieces of great architectural effect. In the case of a light concrete in which the presence of lightweight aggregates is harmful to mechanical strength, it is important to choose a higher strength class. On the other hand, using a low carbon Portland cement with limestone addition will provide a concrete with lower heat of hydration, less shrinkage and better workability than would be expected with a CEM I cement of the same class.

Photo credit: António Alfarroba

Construction type: Non-residential/office building/thermally activated structure

Cement type: CEM II

Sustainable features: Renewable energy/geothermal energy/thermally activated slabs

Via Célere’s Headquarters is an office building in which the slabs are thermally activated by means of a heat pump combined with a geothermal system. Cooling power reaches 113.9 kW and EER is 5.78, whereas heating power reaches 73.3 kW with a COP of 4.34. The concrete slabs are 25 cm thick and have a mortar overlay of 7 cm. The concrete used is a conventional reinforced concrete C25/30. The activation is made by means of PEX pipes with a diameter of 20 mm. Pumping temperature is 15 ºC in Summer and 30 ºC in Winter.

The heat produced that is not used by the office building is given to the hotel next to it for domestic hot water. This way, the hotel will take advantage of the office’s leftover temperature and will heat up the sanitary hot water for no cost thanks to the geothermal installation. At the same time, the geothermal system benefits because the soil is not heated and the thermal gradient lasts for longer.

Construction type: Residential building/sustainable housing (multi dwelling).

Cement type: CEM II/B-V and CEM I with SCM of slag or fly ash through Equivalent Performance of Combinations Concept (EPCC).

Sustainable features: LCA Impact assessment concrete vs. wood / High standard Environmental Certificate

Brf Viva is a cooperative housing block of multi-occupancy buildings that is one of Sweden’s most sustainable and innovative housing projects. The block of seven buildings has a total of 132 apartments.

The project is based on the findings of interdisciplinary research with a holistic approach that incorporates social, environmental and economic sustainability. Some of the features that Brf Viva offers are innovations for housing for young people, innovative mobility solutions for residents without cars, and attention to ecosystem services. Riksbyggen, the property owner, has won an award for its work and the property itself is certified as compliant with the highest environmental standards.

More specifically, the buildings are part of a plus energy block which, apart from being highly energy-efficient, combines thermal mass and solar panels with an energy storage system (reused bus batteries) to provide fossil-free electricity to the block at peak power times.

The property developer looked into both the options of concrete and wooden construction. An environmental impact assessment was undertaken together with leading LCA/EPD experts in wood (SP Trä) and concrete (CBI). Their joint report showed that according to EN 15978 for environmental building performances there were no significant differences regarding global warming potential between the concrete and wooden constructions. Since the building is located on a steep slope, the basement construction was done with cast in place concrete. Based on this finding and the fact that concrete requires less maintenance over its lifetime, Riksbyggen chose concrete as the construction material for the whole building. Finally, the property developer’s requirements stipulated a maximum binder content of 325-400 kg/m3 concrete, depending on the building component, and normally a maximum clinker content of 70%. EPDs were also required for reinforcement.

A review report of the construction project shows that the global warming potential of the building was approximately 30% lower than a traditional concrete structure. Furthermore, it was found that the reduced global warming potential could have been 40% if closer contact with the designers and contractor had also been stipulated as a requirement. The concrete composition did not affect the project schedule.

Photo: Riksbyggen

Construction type: Residential building / apartment building

Cement type: Resource-saving cement: Portland Cement ZN/D 32,5 R

Sustainable features: Building material cycle closing by material reuse

The first resource-conserving cement (R-cement) in Switzerland has been developed, under the name Susteno, in which industrially processed mixed granulate as well as burnt shale are used as an additive. Thanks to the recovery and reuse of processed mixed granulate from the region, the building material cycle is closed. Moreover, the recycled aggregates fraction used are fines, which were so far mostly landfilled or used in low-grade concrete applications. This conserves resources, saves landfill space and reduces emissions.

It was recently used for the construction of the housing development Guggach II near Zurich. Its uses range from simple applications to demanding fair-faced concrete for various structural elements such as columns, walls and ceilings.

The consistently good processability of the installed concretes under various climatic conditions was convincing. Thanks to the pigmentation of the concrete, its outer walls appear in light yellow. Special matrices were used for flower structures on the outer walls.

Both the cement and the aggregates used for the concrete were produced on the basis of industrially processed recycled granulate. Mixed granulate was used for the cement and concrete granulate for the concrete. The water required for the concrete production also comes from the production cycle.

This housing development is a good example how recycled construction materials can be used for sophisticated concrete structures while saving primary resources, reducing carbon emissions and saving landfill space.

Construction type: Residential & non-residential building/skyscraper

Concrete type: High Strength concrete

Cement type: CEM I replaced by 70% ggbs using the Equivalent Performance of Combinations Concept (EPCC)

Sustainable features: Material efficiency, recycled materials, reuse of previous concrete structure, renewable energy, solar energy, thermally activated slabs

At 72 storeys, The Shard is the UK’s tallest building and is so named because of its slender, spire-like shape covered with facets of angled glazing that intends to reflect light and the changing patterns of the sky.

At the building’s heart is a high-performance concrete core, which utilized an innovative use of top-down construction with concrete that achieved 30 MPa cube strength within just 24 hours.

Levels 40 to 72, which include the luxury hotel and residences, were constructed using post-tensioned concrete on high strength (C65/80) concrete columns which offered both material efficiency as well as superior occupant comfort.

The concrete used within the extensive foundations contains a cement blend using 70% ground granulated blast-furnace slag to limit early heat gain and to increase the building’s sustainability credentials. 

The case was originally published on UK’s Mineral Products Association‘s website, and included here with their agreement.