Life Cycle Assessment of LC3: Parameters and Prognoses
01 Jan 2020-Vol. 25, pp 277-281
TL;DR: In this paper, the potential reduction in the environmental impact due to the production of limestone calcined clay cement (LC3), with respect to ordinary portland cement (OPC) and fly ash-based portland pozzolana cement (PPC), was investigated.
Abstract: Life cycle assessment (LCA) has been conducted to obtain the potential reduction in the environmental impact due to the production of limestone calcined clay cement (LC3), with respect to ordinary portland cement (OPC) and fly ash-based portland pozzolana cement (PPC). A case study of a typical cement plant in South India is considered. It is found, for this particular case and the assumptions made, that the CO2 emissions and the energy demand could decrease by 34% and 18%, respectively, if LC3 is used instead of OPC, with the corresponding reductions being 26% and 21% for PPC. A parametric study of some key factors that could influence the impact of LC3 showed that the CO2 emissions and the energy demand could vary by 13% and 20%, respectively, with variations in the calcination energy requirement while the clay transportation distance did not have any significant influence.
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TL;DR: In this article, a prospective approach to conduct sustainability assessment based on the life cycle of 3D printed structures is presented, which also highlights the importance of considering the functional requirements of the mixes used for 3D printing.
Abstract: This paper explores the sustainability aspects of binders used in concrete 3D concrete printing. Firstly, a prospective approach to conduct sustainability-assessment based on the life cycle of 3D printed structures is presented, which also highlights the importance of considering the functional requirements of the mixes used for 3D printing. The potential of the material production phase is emphasized to enhance the sustainability potential of 3DCP by reducing the embodied impacts. The literature on the different binder systems used for producing 3D printable mixtures is reviewed. This review includes binders based on portland cement and supplementary cementing materials (SCMs) such as fly ash, silica-fume and slag. Also, alternative binders such as geopolymer, calcium sulfo-aluminate cement (CSA), limestone calcined clay cement (LC3) and reactive magnesium oxide systems are explored. Finally, sustainability assessment by quantifying the environmental impacts in terms of energy consumed and CO2 emissions of mixtures is illustrated with different binder systems. This paper underlines the effect of using SCMs and alternative binder systems for improving the sustainability of 3D printed structures.
4 citations
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TL;DR: In this article, the authors analyzed the mechanical and environmental performance of an alternative low-carbon cement (Limestone Calcined Clay Cement, LC3) made from different Brazilian natural and waste clay-based materials.
Abstract: This study analyzed the mechanical and environmental performance of an alternative low-carbon cement (Limestone Calcined Clay Cement, LC3) made from different Brazilian natural and waste clay-based materials. Data from an extensive laboratory program to characterize the alternative materials have been utilized. A Life Cycle Assessment (LCA) based on a cradle-to-gate approach was also performed. The results give decision-makers and the cement industry a better understanding of environmental impact at regional, national, and local levels. Moreover, this study opens a new perspective on the natural and waste clay-based materials to further the production of eco-efficient cements in Brazil and other countries.
References
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TL;DR: The main conclusions of an analysis of low-CO2, eco-efficient cement-based materials, carried out by a multi-stakeholder working group initiated by the United Nations Environment Program Sustainable Building and Climate Initiative (UNEP-SBCI) are presented, based on the white papers published in this special issue as discussed by the authors.
Abstract: The main conclusions of an analysis of low-CO2, eco-efficient cement-based materials, carried out by a multi-stakeholder working group initiated by the United Nations Environment Program Sustainable Building and Climate Initiative (UNEP-SBCI) are presented, based on the white papers published in this special issue. We believe that Portland-based cement approaches will dominate in the near future due to economies of scale, levels of process optimisation, availability of raw materials and market confidence. Two product-based approaches can deliver substantial additional reductions in their global CO2 emissions, reducing the need for costly investment in carbon capture and storage (CCS) over the next 20–30 years: 1. Increased use of low-CO2 supplements (SCMs) as partial replacements for Portland cement clinker. 2. More efficient use of Portland cement clinker in mortars and concretes. However, other emerging technologies could also play an important role in emissions mitigation in the longer term, and thus merit further investigation.
635 citations
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TL;DR: In this article, the authors presented data on the chloride diffusion coefficient (Dcl), ageing coefficient (m) and chloride threshold (Clth) related to seven concrete mixes (four M35 and three M50) with OPC, OPC+PFA (pulverised fuel ash) and limestone-calcined clay cement (LC3).
Abstract: This paper presents data on the chloride diffusion coefficient (Dcl), ageing coefficient (m) and chloride threshold (Clth) related to seven concrete mixes (four M35 and three M50) with OPC, OPC + PFA (pulverised fuel ash) and limestone-calcined clay cement (LC3). Using these, the service lives of a typical bridge pier and girder with the PFA and LC3 concrete were found to be much higher than those with OPC concrete of similar strength. From life-cycle assessment, the CO2 footprint of PFA and LC3 concrete were found to be significantly lower than those of OPC concrete of similar strength. Further, the CO2 emissions per unit of concrete per year of estimated service life, as a combined indicator of service life and carbon footprint, are similar for concrete with PFA and LC3, which are much lower than that with OPC.
51 citations
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TL;DR: In this paper, the authors proposed a framework for sustainability assessment, in terms of the CO2 emissions and energy demand, that can be adopted in cases where suitable databases are not readily available.
Abstract: The consumption of cement in India and other emerging economies is expected to increase because of the continuing push towards development of housing and infrastructure. The increasing production of cement and utilization of concrete are bound to have a major impact on sustainability. The present work proposes a framework for sustainability assessment, in terms of the CO2 emissions and energy demand, that can be adopted in cases where suitable databases are not readily available. Case studies for cement manufacture have been considered in South India, with different system boundaries such as ground-to-gate, gate-to-gate and CSI. The assessment made using data from the plant and other sources highlights the benefits of using supplementary cementitious materials (SCMs) in terms of reducing the impact of cement and concrete. More importantly, limestone calcined clay cement shows considerable promise in terms of reduction in CO2 emissions and energy demand in both cement and concrete, with more improvement in higher grade concrete.
34 citations
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TL;DR: In this article, a decision support framework is proposed, along with two objective indices, for the selection of concrete mixture proportions based on sustainability criteria, which combine energy demand and long-term strength as energy intensity, and carbon emissions and durability parameters as A-indices.
Abstract: A framework is proposed, along with two objective indices, for the selection of concrete mixture proportions based on sustainability criteria. The indices combine energy demand and long-term strength as energy intensity, and carbon emissions and durability parameters as A-indices, which represent the apathy toward these essential features of sustainability. The decision support framework is demonstrated by considering a set of 30 concretes with different binders, including ordinary portland cement (OPC), fly ash, slag and limestone calcined clay cement (LC3). In addition to the experimental data on compressive strength, chloride diffusion and carbonation, life cycle assessment has been performed for the concretes considering typical situations in South India. The most sustainable of the concretes studied here, for service life limited by chloride ingress, are those with LC3, OPC replaced by 50% slag, and ternary blends with 20% each of slag and fly ash. In the case of applications where carbonation is critical, the appropriate concretes are those with OPC replaced by 15–30% slag or 15% fly ash, or with ternary blends having 20% slag and 20% Class F fly ash.
18 citations