AAC in the USA – A second look

Fouad, Fouad H.; Schoch, Torsten

doi:10.1002/cepa.902

Cited by 8 publications

(5 citation statements)

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“…Globally, a production capacity of 450 million m 3 for non‐reinforced AAC blocks is prevalent [8]. In Europe, AAC volumes sum up and are expected to remain steady at around 17.5 million m 3 per year for the foreseeable future [9], whereas the German AAC industry achieved a production volume of approximately 3,110,000 m 3 non‐reinforced AAC blocks and elements in the reference year 2019 (this number refers to 12 companies with a total of 24 production sites being organised in the associations Verband Bauen in Weiß e.V.…”

Section: Aac Production‐ and Waste‐volumesmentioning

confidence: 99%

Circular economy's potential to reduce AAC carbon emissions

Kreft¹

2022

ce papers

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Establishing a circular economy for Xella's building materials – among them Autoclaved Aerated Concrete (AAC) – is and will be one of Xella's key ESG projects for the coming years. In Germany, Xella has made it its goal to duplicate the powder‐input in the main AAC‐products from annually 60,000 t to 120,000 t by 2030. AAC‐powder used today emerges from the processing of AAC production leftovers, cutting residues and leftovers returned from job sites. In order to achieve the 2030 goal, Xella Germany will (1) generate new sinks, and (2) leverage new sources for AAC‐powder. Current production recipes are designed to take up emerging powder‐quantities, but nothing beyond. The present study describes the inspection and evaluation of current powder input shares per product type and options for their full exploitation by recipe amendments. In 2021, prototypes for Ytong PP2‐0,35 and PP4‐0,50 containing 20 m.‐% powder, and Ytong PP4‐0,55 containing 30 m.‐% powder were developed by the Xella Technologie‐ und Forschungsgesellschaft mbH. In order to prospectively supply sufficient quantities of AAC‐powder, Xella Germany aims at leveraging waste‐AAC from building demolition, so called “post‐demolition AAC” or “pd‐AAC”. We combined the “zero burden” and the “avoided burden methodology” to expand the life cycle assessment for the investigated circularity scenarios over the edge of waste generation. Our assessment revealed substitution credits of 0.55 kg CO2e/kg pd‐AAC for Ytong PP2‐0,35, and 0.43 respectively 0.33 kg CO2e/kg pd‐AAC for Ytong PP4‐050 and PP4‐0,55. The present study illustrates that our ambition to duplicate Xella Germany's powder consumption is achievable, when the new formulations are fully and consequently implemented. The recipe amendments have the potential to reduce expenditures for sand, quicklime, cement and gypsum/anhydrite, thereby reducing Xella Germany's annual (Scope 3) AAC carbon emissions up to 36 kt CO2e.

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Section: Aac Production‐ and Waste‐volumesmentioning

confidence: 99%

Circular economy's potential to reduce AAC carbon emissions

Kreft¹

2022

ce papers

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“…Autoclaved aerated concrete (AAC) was invented in 1923, and extensively used worldwide. The estimated yearly worldwide production of AAC (non-reinforced) in recent years sums up to 450 million m 3 (Fouad & Schoch, 2018). It holds 16% of total construction in India; whereas, in the UK and Germany it contributes over 40 and 60% of total construction (Subash et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Utilization of Solid Waste in the Production of Autoclaved Aerated Concrete and Their Effects on its Physio-mechanical and Microstructural Properties: Alternative Sources, Characterization, and Performance Insights

Abhilasha

Kumar

Lakhani

et al. 2023

Int J Concr Struct Mater

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Autoclaved aerated concrete (AAC) is the lightest masonry material available in today’s building industry. It shows properties, such as high strength per unit weight, lesser density, lower shrinkage, higher thermal insulation, and fire resistance as compared to traditional concrete. Not only engineering properties of AAC make it popular in construction industry, but also its eco-friendly nature also contributes in conservation of energy. AAC produces about 67% lower carbon emission than the clay bricks. Consequently, it becomes a cost-effective product which reduces the cost of construction. This paper provides thorough insight into possible solutions for the waste utilization. It has been inferred that fine aggregates can be replaced by these wastes in the preparation of AAC. This replacement will improve its physio-mechanical properties, such as bulk-density, moisture absorption, compressive strength, along with microstructure. These properties are comprehensively presented to categorize the investigation which has been done in such fields earlier. The ongoing research work at the author’s institute, i.e., the development of lightweight concrete by using different kind of waste materials, such as marble slurry, fly ash, etc., is being presented. Graphical Abstract

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“…Small amounts of aluminium added to the suspension start a chemical reaction that produces hydrogen leading to the porous structure. Currently, the global production capacity for non-reinforced AAC blocks is around 450 million m³ [3], and the European AAC production exceeds 16 million m³ annually [4]. Currently, post-demolition AAC (pd-AAC) amounts are enormously increasing.…”

Section: Introduction and Literaturementioning

confidence: 99%

Designing a new recycling network for post-demolition autoclaved aerated concrete (AAC) in Europe

Steins

Volk

Stallkamp

et al. 2023

IOP Conf. Ser.: Earth Environ. Sci.

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Autoclaved aerated concrete (AAC) is a widely used building material for masonry blocks. Its porous structure and mineral composition lead to low thermal conductivity and fire resistance. European AAC production and usage strongly increased in the 1960s and 1970s. Therefore, assuming limited buildings’ lifetimes, significant post-demolition AAC volumes can be expected in the following decades. However, post-demolition AAC recycling in high-value environmentally friendly applications is still to be established as most post-demolition AAC is currently landfilled. Different recycling options for post-demolition AAC are presently being researched. However, a recycling network to implement these options is neither designed nor established. This contribution focuses on creating a European recycling network, including mathematical modelling, data acquisition, and solving the model. i.e. minimising the total costs. The mathematical modelling uses a capacitated warehouse location problem with multi-sourcing and direct delivery. Results show that recycling plants of smaller capacity (100,000 t input/a) are placed in the recycling networks in 2020 and 2025. With higher waste quantities being expected from 2030 onwards, plants with a larger capacity (200,000 t input/a) are added, especially in Poland, where the highest pd-AAC amount in Europe is expected. The recycling network shows a decentralised structure with numerous recycling plants to keep transport costs low. Most network costs result from variable processing costs, showing the highest cost increases from 2020 to 2050. Fixed costs increase with the higher number of recycling plants and account for the second-largest share of total network costs. Transport costs are comparatively low thanks to the decentralised structure of the network. Overall, waste generation is expected to increase by 226% from 2020 to 2050, while the total costs of the recycling network are expected to rise by 151% only. The results support decision-makers in fostering recycling and implementing a circular economy for post-demolition AAC.

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AAC in the USA – A second look

Cited by 8 publications

References 0 publications

Circular economy's potential to reduce AAC carbon emissions

Circular economy's potential to reduce AAC carbon emissions

Utilization of Solid Waste in the Production of Autoclaved Aerated Concrete and Their Effects on its Physio-mechanical and Microstructural Properties: Alternative Sources, Characterization, and Performance Insights

Designing a new recycling network for post-demolition autoclaved aerated concrete (AAC) in Europe

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