Life Cycle Assessment of 3D Printing Geo-polymer Concrete: An Ex-ante Study

Three-dimensional (3D) printing and geo-polymers are two environmentally oriented innovations in concrete manufacturing. The 3D printing of concrete components aims to reduce raw material consumption and waste generation. Geo-polymer is being developed to replace ordinary Portland cement and reduce the carbon footprint of the binder in the concrete. The environmental performance of the combined use of the two innovations is evaluated through an ex-ante life cycle assessment (LCA). First, an attributional LCA was implemented, using data collected from the manufacturer to identify the hotspots for environmental improvements. Then, scaled-up scenarios were built in collaboration with the company stakeholder. These scenarios were compared with the existing production system to understand the potential advantages/disadvantages of the innovative system and to identify the potential directions for improvement. The results indicate that 3D printing can potentially lead to waste reduction. However, depending on its recipe, geo-polymer likely has higher environmental impacts than ordinary concrete. The ex-ante LCA suggests that after step-by-step improvements in the production and transportation of raw materials, 3D printing geo-polymer concrete is able to reduce the carbon footprint of concrete components, while it does still perform worse on impact categories, such as depletion of abiotic resources and stratospheric ozone depletion. We found that the most effective way to lower the environmental impacts of 3D concrete is to reduce silicate in the recipe of the geo-polymer. This approach is, however, challenging to realize by the company due to the locked-in effect of the previous innovation investment. The case study shows that to support technological innovation ex-ante LCA has to be implemented as early as possible in innovation to allow for maintaining technical flexibility and improving on the identified hotspots.Resources & Recyclin

An overview of the waste hierarchy framework for analyzing the circularity in construction and demolition waste management in Europe

The construction sector is the biggest driver of resource consumption and waste generation in Europe. The European Union (EU) is making efforts to move from its traditional linear resource and waste management system in the construction sector to a level of high circularity. Based on the theory of circular economy, a new paradigm called waste hierarchy was introduced in the EU Waste Framework Directive. This work uses the framework of the waste hierarchy to analyze the practice of construction and demolition waste (CDW) management in Europe. We explore the evolution of the waste hierarchy in Europe and how it compares with the circular economy. Then, based on the framework, we analyze the performance of CDW management in each EU member state. Innovative treatment methods of CDW, focusing on waste concrete, is investigated. This brings insight into optimizing and upgrading the CDW management in light of advanced technologies and steering the pathway for transitioning the EU towards a circular society.Resources & RecyclingDesign for Sustainabilit

The evolution and future perspectives of energy intensity in the global building sector 1971–2060

Energy efficiency plays an essential role in energy conservation and emissions mitigation efforts in the building sector. This is especially important considering that the global building stock is expected to rapidly expand in the years to come. In this study, a global-scale modeling framework is developed to analyze the evolution of building energy intensity per floor area during 1971–2014, its relationship with economic development, and its future role in energy savings across 21 world regions by 2060. Results show that, for residential buildings, while most high-income and upper-middle-income regions see decreasing energy intensities and strong decoupling from economic development, the potential for further efficiency improvement is limited in the absence of significant socioeconomic and technological shifts. Lower-middle-income regions, often overlooked in analyses, will see large potential future residential energy savings from energy intensity reductions. Harnessing this potential will include, among other policies, stricter building efficiency standards in new construction. For the commercial sector, during 1971–2014, the energy intensity was reduced by 50% in high-income regions but increased by 193% and 44% in upper-middle and lower-middle-income regions, respectively. Given the large energy intensity reduction potential and rapid floor area growth, commercial buildings are increasingly important for energy saving in the future.Mathematical Physic

Eco-efficiency assessment of technological innovations in high-grade concrete recycling

The increasing volume of Construction and demolition waste (CDW) associated with economic growth is posing challenges to the sustainable management of the built environment. The largest fraction of all the CDW generated in the member states of the European Union (EU) is End-of-life (EOL) concrete. The most widely applied method for EOL concrete recovery in Europe is road base backfilling, which is considered low-grade recovery. The common practice for high-grade recycling is wet process that processes and washes EOL concrete into clean coarse aggregate for concrete manufacturing. It is costly. As a result, a series of EU projects have been launched to advance the technologies for high value-added concrete recycling. A critical environmental and economic evaluation of such technological innovations is important to inform decision making, while there has been a lack of studies in this field. Hence the present study aimed to assess the efficiency of the technical innovations in high-grade concrete recycling, using an improved eco-efficiency analytical approach by integrating life cycle assessment (LCA) and life cycle costing (LCC). Four systems of high-grade concrete recycling were analyzed for comparison: (i) business-as-usual (BAU) stationary wet processing; (ii) stationary advanced dry recovery (ADR); (iii) mobile ADR; (iv) mobile ADR and Heating Air Classification (A&H). An overarching framework was proposed for LCA/LCC-type eco-efficiency assessment conforming to ISO standards. The study found that technological routes that recycle on-site and produce high-value secondary products are most advantageous. Accordingly, policy recommendations are proposed to support the technological innovations of CDW management.Resources & Recyclin

Closing the loop of EOL concrete

Production of waste materials, via industrial and human activities, creates big environmental and economic problems but also opportunities to recover valuable resources. EU28 currently generates 461 million tons per year of ever more complex Construction and Demolition Waste (CDW) with average recycling rates of around 46%. There is still a significant loss of potential valuable minerals, metals and organic materials all over Europe. Considering the fact that public and private sectors have become aware of the urgency and importance of CDW recycling, the European Commission has taken initiatives towards sustainable treatment and recycling of CDW funding three tandem projects focusing on the development of an innovative and sustainable concrete recycling process. To that end, this article will firstly present the main achievements and ongoing activities for developing the innovative concrete recycling technology in the course of the EU C2CA, HISER and VEEP projects. In addition some figures related to the cost of each recycling unit process and the selling price of the recycled products are presented

Life cycle assessment of material footprint in recycling: A case of concrete recycling

Meeting the current demand for concrete requires not only mining tons of gravel and sand, but also burning large amounts of fossil fuel resources in cement kilning. Consequently, concrete recycling is crucial to achieving a material-efficient society, especially with the application of various categories of concrete and the goal of phasing out fossil fuels. A comparative life cycle assessment (LCA) is used to assess the engineering material footprint (EMF) and the fossil fuel material footprint (FMF) in closed-loop recycling of three types of concrete: siliceous concrete, limestone concrete, and lightweight aggregate concrete. This study aims to investigate the impact of (i) concrete categories, (ii) methods to model recycling, and (iii) using renewable energy sources on the material footprint in concrete recycling. The results highlight that the concrete recycling system can reduce 99% of the EMF and 66–93% of the FMF compared with the baseline system, in which concrete waste is landfilled. All three recycling modeling approaches indicate that concrete recycling can considerably reduce EMF and FMF compared with the baseline system, primarily resulting from the displacement of virgin raw materials. Using alternative diesels is more sensitive than adopting renewable electricity in reduction of the FMF in concrete recycling. Replacing diesel with electrolysis- and coal-based synthetic diesel for concrete recycling could even increase the FMF, while using biodiesel made from rapeseed and wood-based synthetic diesel can reduce 47–51% and 84–89% of the FMF, respectively, compared to the virgin diesel-based recycling system. Finally, we discussed the multifunctionality and rebound effects of recycling, and double-counting risk in material and energy accounting.Resources & Recyclin

Phytoplankton and bacterioplankton abundances and community dynamics in Lake Erhai

The composition and seasonal variation of the phytoplankton and bacterioplankton community were investigated, and SPSS and redundancy analysis (RDA) were used to explore the relationship between the phytoplankton and bacterioplankton community dynamics in the typical plateau Lake of Lake Erhai from July 2009 to April 2010. Obvious seasonal variation of phytoplankton was observed, and the abundance of phytoplankton ranged from 2.02 x 10(6) to 57.9 x 10(6) cells/L. The dominant species in autumn and summer was Microcystis sp., Psephonema aenigmaticum Skuja was dominant in winter, and Microcystis sp., Aphanizonmenon flos-aquae, Asterionella sp., P. aenigmaticum, etc. were dominant in spring. The abundance of bacterioplankton in the whole lake changed between 1.93 x 10(9) and 4.61 x 10(9) cells/L showing distinct seasonal variation characteristics. The results of correlation and RDA indicated that the abundance and community diversity of bacterioplankton were significantly correlated with the abundance of phytoplankton, and the group of Bacteroidetes had obvious correlation with Microcystis sp. and other cyanobacteria, which might have some links with the harmful algal blooms in Lake Erhai. Further research is needed to study the mechanisms of interactions between phytoplankton and bacterioplankton communities.The composition and seasonal variation of the phytoplankton and bacterioplankton community were investigated, and SPSS and redundancy analysis (RDA) were used to explore the relationship between the phytoplankton and bacterioplankton community dynamics in the typical plateau Lake of Lake Erhai from July 2009 to April 2010. Obvious seasonal variation of phytoplankton was observed, and the abundance of phytoplankton ranged from 2.02 x 10(6) to 57.9 x 10(6) cells/L. The dominant species in autumn and summer was Microcystis sp., Psephonema aenigmaticum Skuja was dominant in winter, and Microcystis sp., Aphanizonmenon flos-aquae, Asterionella sp., P. aenigmaticum, etc. were dominant in spring. The abundance of bacterioplankton in the whole lake changed between 1.93 x 10(9) and 4.61 x 10(9) cells/L showing distinct seasonal variation characteristics. The results of correlation and RDA indicated that the abundance and community diversity of bacterioplankton were significantly correlated with the abundance of phytoplankton, and the group of Bacteroidetes had obvious correlation with Microcystis sp. and other cyanobacteria, which might have some links with the harmful algal blooms in Lake Erhai. Further research is needed to study the mechanisms of interactions between phytoplankton and bacterioplankton communities

SEASONAL DYNAMICS AND PHYLOGENETIC ANALYSIS OF BACTERIOPLANKTON IN LAKE ERNAI, SW-CHINA

The community composition and seasonal variation of bacterioplankton were investigated using 16S rRNA gene sequence analysis in high mount Lake Erhai, China. Restriction fragment length polymorphism (RFLP) analysis revealed remarkable seasonal fluctuations in bacterio-planktonic composition. A total of 1498 clones were obtained from 16 water samples, and most of clones belonged to the clusters alpha-Proteobacteria, beta-Proteobacteria, gamma-Proteobacteria, Actinobacteria, Bacteroidetes, Verrucomicrobia, and Cyanobacteria. Among these groups, alpha-Proteobacteria was the identified as most dominant group in spring and summer. However, the structure shifted toward a beta-Proteobacterium-dominant community in autumn and winter. The clone libraries were found having the greatest diversity in winter, and some species only appeared in their specific seasons. The number of operational taxanomic uints (OTUs) predicted for the Lake Erhai ranged from 42.7 to 98.0, significantly lower than the samples from low-altitude lakes. The results of partial redundancy analysis (RDA) showed that environmental factors associated with nitrogen could play an important role in driving the conversion of two major groups in Lake Erhai. The present study indicated that the bacterio-plankton communities of Erhai Lake were similar to other freshwater ecosystems as many sequences showed 93.8% - 100% homology with known sequences found in other freshwater ecosystems, but had many unique characteristics. And also part of communities predicted to be from marine ecosystems.These findings provided fundamental and specofic information on the structure of bacterioplankton and the microfood web in Lake Erhai.The community composition and seasonal variation of bacterioplankton were investigated using 16S rRNA gene sequence analysis in high mount Lake Erhai, China. Restriction fragment length polymorphism (RFLP) analysis revealed remarkable seasonal fluctuations in bacterio-planktonic composition. A total of 1498 clones were obtained from 16 water samples, and most of clones belonged to the clusters alpha-Proteobacteria, beta-Proteobacteria, gamma-Proteobacteria, Actinobacteria, Bacteroidetes, Verrucomicrobia, and Cyanobacteria. Among these groups, alpha-Proteobacteria was the identified as most dominant group in spring and summer. However, the structure shifted toward a beta-Proteobacterium-dominant community in autumn and winter. The clone libraries were found having the greatest diversity in winter, and some species only appeared in their specific seasons. The number of operational taxanomic uints (OTUs) predicted for the Lake Erhai ranged from 42.7 to 98.0, significantly lower than the samples from low-altitude lakes. The results of partial redundancy analysis (RDA) showed that environmental factors associated with nitrogen could play an important role in driving the conversion of two major groups in Lake Erhai. The present study indicated that the bacterio-plankton communities of Erhai Lake were similar to other freshwater ecosystems as many sequences showed 93.8% - 100% homology with known sequences found in other freshwater ecosystems, but had many unique characteristics. And also part of communities predicted to be from marine ecosystems.These findings provided fundamental and specofic information on the structure of bacterioplankton and the microfood web in Lake Erhai

C-Reactive Protein Induces Interleukin-6 and Thrombospondin-1 Protein and mRNA Expression through Activation of Nuclear Factor-kappa B in HK-2 Cells

Background: Although C-reactive protein (CRP) is significantly increased in patients with diabetic nephropathy, whether CRP exerts direct proinflammatory effects on human renal tubular epithelial cells (HK-2 cells) is still unclear. Methods: HK-2 cells were incubated with purified CRP at clinically relevant concentrations (0, 5, 10, 20 and 40 mu g/ml). The protein and transcript levels of thrombospondin-1 (TSP-1) and interleukin-6 (IL-6) were determined by ELISA and RT-PCR. Phosphorylation of p38MAPK was investigated through Western blot analysis in HK-2 cells induced by CRP. The activation of nuclear factor-kappa B (NF-kappa B) was studied via EMSA. A specific p38MAPK inhibitor (SB203580) and an NF-kappa B inhibitor (PDTC; pyrrolidine dithiocarbamate) were used to analyze the signal transduction in CRP induction. To explore the direct or indirect role of CRP in HK-2 cells, IL-6 or TSP-1 antibodies were used. The expression of IL-6, TSP-1 and transforming growth factor-beta(1) (TGF-beta(1)) were determined through Western blot analysis in HK-2 cells. Results: In HK-2 cells, purified CRP significantly induced protein release and mRNA expression of IL-6 and TSP-1 in a dose- and time-dependent manner. TGF-beta(1) protein was overexpressed in HK-2 cells induced by CRP, which cannot be inhibited by IL-6 or TSP-1 antibodies. CRP triggered phosphorylation of p38MAPK and activation of NF-kappa B-mediated signal transduction. SB203580 (5 mu m) and PDTC (50 mu m) efficiently suppressed those effects of CRP in HK-2 cells. Conclusions: CRP induces IL-6 and TSP-1 protein release and mRNA expression from HK-2 cells via activation of the p38MAPK and NF-kappa B signaling pathways and TGE-beta(1) was highly expressed in HK-2 cells, suggesting that CRP plays an important role in the propagation and prolongation of inflammation in renal fibrosis. Copyright (C) 2012 S. Karger AG, BaselBackground: Although C-reactive protein (CRP) is significantly increased in patients with diabetic nephropathy, whether CRP exerts direct proinflammatory effects on human renal tubular epithelial cells (HK-2 cells) is still unclear. Methods: HK-2 cells were incubated with purified CRP at clinically relevant concentrations (0, 5, 10, 20 and 40 mu g/ml). The protein and transcript levels of thrombospondin-1 (TSP-1) and interleukin-6 (IL-6) were determined by ELISA and RT-PCR. Phosphorylation of p38MAPK was investigated through Western blot analysis in HK-2 cells induced by CRP. The activation of nuclear factor-kappa B (NF-kappa B) was studied via EMSA. A specific p38MAPK inhibitor (SB203580) and an NF-kappa B inhibitor (PDTC; pyrrolidine dithiocarbamate) were used to analyze the signal transduction in CRP induction. To explore the direct or indirect role of CRP in HK-2 cells, IL-6 or TSP-1 antibodies were used. The expression of IL-6, TSP-1 and transforming growth factor-beta(1) (TGF-beta(1)) were determined through Western blot analysis in HK-2 cells. Results: In HK-2 cells, purified CRP significantly induced protein release and mRNA expression of IL-6 and TSP-1 in a dose- and time-dependent manner. TGF-beta(1) protein was overexpressed in HK-2 cells induced by CRP, which cannot be inhibited by IL-6 or TSP-1 antibodies. CRP triggered phosphorylation of p38MAPK and activation of NF-kappa B-mediated signal transduction. SB203580 (5 mu m) and PDTC (50 mu m) efficiently suppressed those effects of CRP in HK-2 cells. Conclusions: CRP induces IL-6 and TSP-1 protein release and mRNA expression from HK-2 cells via activation of the p38MAPK and NF-kappa B signaling pathways and TGE-beta(1) was highly expressed in HK-2 cells, suggesting that CRP plays an important role in the propagation and prolongation of inflammation in renal fibrosis. Copyright (C) 2012 S. Karger AG, Base

SUCCESSION OF THE PHYTOPLANKTON COMMUNITY IN RESPONSE TO ENVIRONMENTAL FACTORS IN NORTH LAKE ERHAI DURING 2009-2010

Phytoplankton samples were taken weekly from September 2009 to November 2010 in Lake Erhai. The purpose was to obtain detailed information about the composition variations in the phytoplankton community during the serious drought in 2009 - 2010 and to determine the driving force for the succession of the dominant genera. A total of 147 phytoplankton species were identified during our investigation. Among the 7 main divisions, the maximum contribution (69%) belongs to the Chlorophyta division. The alternation of the dominant group was Cyanophyta, Chlorophyta, and Bacillariophyta. The weekly variations in cell abundance and biomass of the dominant phytoplankton genera were examined. A succession characterized by Psephonema and Asterionella (spring) -> Melosira (summer) -> Microcystis (autumn) -> Microcystis and Psephonema (winter) emerged from the monthly average biomass. Weekly variations in the Shannon Weaver index ranged between 0.269 and 2.183. Redundancy analysis results showed varied effects of environmental factors on the different phytoplankton dominant genera, with water temperature as the driving force for the seasonal succession of the dominant genera. The shift in succession pattern is induced by light intensity variation. In addition, the dominance of Psephonema in winter is the first report in Lake Erhai in recent years