Analysis of the environmental impacts of alkali-activated concrete produced with waste glass-derived silicate activator – A LCA study

Bianco, Isabella; Tomos, Branwen Ap Dafydd; Vinai, Raffaele

doi:10.1016/j.jclepro.2021.128383

Cited by 73 publications

(18 citation statements)

References 40 publications

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“…The environmental investigation carried out using life cycle assessment tools by Bianco et al 9 suggested that alkali-activated concrete produced with waste glass-based activator obtained through the same thermochemical method adopted in this study resulted in carbon emissions of about 100-120 kgCO 2eq /m 3 for concretes having compressive strength in the range 35-50 MPa. In the same study, CO 2 emissions of Portland cement-based concretes were calculated in the range 333 to 409 kgCO 2eq /m 3 for equivalent strength classes.…”

Section: Environmental Implicationsmentioning

confidence: 88%

“…The study highlighted that the grinding of glass had a marginal impact on the emissions of the waste-derived activator, and about 67-69 kg of activating powder was required for about 355-370 kg of the binder. 7,9 The mix proportions shown in Table 2 (see Section 2.2) were in the same order of magnitude (about 100 g of powder for 500 g of binder, which corresponds to 72 kg of powder for 360 kg of binder), and the compressive strength of mortars was in the range of 40 MPa at 28 days. Since the process for producing the activating powder is the same, the activator dosages are comparable, and the strength is in the same range, it can be assumed that the CO 2 emissions of concrete produced with BL-based activating powder could be in the range 100-120 kgCO 2eq /m 3 .…”

Section: Environmental Implicationsmentioning

confidence: 98%

“…Waste-derived silicate activators for AAM have been proposed, demonstrating the suitability of such alternative activators both in terms of mechanical strength development [5][6][7] and environmental as well as economic benefits. [8][9][10] Several sources of waste-derived silicates have been investigated in the literature for their use as activators. 11 Mining waste such as iron ore tailings, 12 glass waste, 7,13 and silica fume 14,15 are among the inorganic Si-rich waste streams successfully utilized for the production of activators for AAM.…”

Section: Introductionmentioning

confidence: 99%

“…Nanopowders used in AAM technology, 44 metallurgy, 45 and glass technology 46 have been successfully obtained even from waste or by‐products. Waste‐derived silicate activators for AAM have been proposed, demonstrating the suitability of such alternative activators both in terms of mechanical strength development 5–7 and environmental as well as economic benefits 8–10 …”

Section: Introductionmentioning

confidence: 99%

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Bio‐derived sodium silicate for the manufacture of alkali‐activated binders: Use of bamboo leaf ash as silicate source

Vinai

Ntimugura

Cutbill

et al. 2022

Int J Applied Ceramic Tech

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Alkali activated binders are a promising alternative to the use of Portland cement in the manufacture of concrete for curbing CO2 emissions. Novel sources of silicates have been investigated in recent years for reducing cost and environmental impacts associated with the use of chemical activators. This study describes the production of solid sodium silicate (SS) activating powder from bamboo leaf ash (BLA). Bamboo leaves were calcined at 550–800°C, mixed with NaOH pellets, and heated in an oven at 300°C. The obtained silicate powder was used for activating blended fly ash/slag samples. Mechanical and microstructural properties of BLA‐based samples were compared to those of samples made with commercially available chemicals. The strength of BLA‐activated mortars matched the commercially‐sourced activators, being 25–30 MPa at 7 days and exceeding 40 MPa at 28 days. The microstructural analysis suggested that BLA‐based SS showed a lesser degree of dissolution of precursors at 7 days, but the quality of the matrix was higher than that of NaOH‐activated samples. These results confirmed that the reactivity of BLA‐silicate powder was similar to that of commercial SS solutions, and show the potential valorization of future biomass renewable waste in the production of low carbon, alkali‐activated concretes.

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Section: Environmental Implicationsmentioning

confidence: 88%

Section: Environmental Implicationsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Bio‐derived sodium silicate for the manufacture of alkali‐activated binders: Use of bamboo leaf ash as silicate source

Vinai

Ntimugura

Cutbill

et al. 2022

Int J Applied Ceramic Tech

Self Cite

View full text Add to dashboard Cite

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“…The authors concluded that using alternative cementitious materials as cement replacements could significantly reduce the environmental impacts of cement-based products (e.g., AAS concrete had 73% lower GHGs, 43% less energy, and 25% less water). In another study, Bianco et al (2021 ) compared the AAM produced with a silicate activator derived from waste glass (AABR) or with commercially available chemicals (AABC) to ordinary portland cement (OPC). The authors showed that the adoption of alkali-activated concretes instead of OPC concrete allows a significant reduction in environmental categories of global warming potential (64% and 70% reduction for AABC and AABR, respectively), acidification potential (23% and 35% reduction for AABC and AABR, respectively), and terrestrial eutrophication (53% and 60% reduction for AABC and AABR, respectively).…”

Section: Introductionmentioning

confidence: 99%

Environmental and Biological Impact of Fly Ash and Metakaolin-Based Alkali-Activated Foams Obtained at 70°C and Fired at 1,000°C

et al. 2022

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Alkali-activated foams (AAFs) are inorganic porous materials that can be obtained at temperatures well below 100°C with the use of inorganic wastes as aluminosilicate precursors. In this case, fly ash derived from a Slovenian power plant has been investigated. Despite the environmental benefits per se, due to saving of energy and virgin materials, when using waste materials, it is of extreme importance to also evaluate the potential leaching of heavy metal cations from the alkali-activated foams. This article presents an environmental study of a porous geopolymer derived from this particular fly ash, with respect to the leachability of potentially hazardous elements, its environmental toxicity as determined by biological testing, and the environmental impact of its production. In particular, attention was focused to investigate whether or not 1,000°C-fired alkali-activated fly ash and metakaolin-based foams, cured at 70°C, are environmentally friendlier options compared to unfired ones, and attempts to explain the rationale of the results were done. Eventually, the firing process at 1,000°C, apart from improving technical performance, could reinforce heavy metal cation entrapment within the aluminosilicate matrix. Since technical performance was also modified by addition of different types of activators (K-based or Na-based), as well as by partial replacement of fly ash with metakaolin, a life cycle assessment (LCA) analysis was performed to quantify the effect of these additions and processes (curing at 70°C and firing at 1,000°C) in terms of global warming potential. Selected samples were also evaluated in terms of leaching of potentially deleterious elements as well as for the immobilization effect of firing. The leaching test indicated that none of the alkali-activated material is classified as hazardous, not even the as-received fly ash as component of new AAF. All of the alkali-activated foams do meet the requirements for an inertness. The highest impact on bacterial colonies was found in samples that did not undergo firing procedures, i.e., those that were cured at 70°C, which induced the reduction of bacterial Enterococcus faecalis viability. The second family of bacteria tested, Escherichia coli, appeared more resistant to the alkaline environment (pH = 10–12) generated by the unfired AAMs. Cell viability recorded the lowest value for unfired alkali-activated materials produced from fly ash and K-based activators. Its reticulation is only partial, with the leachate solution appearing to be characterized with the most alkaline pH and with the highest ionic conductivity, i.e., highest number of soluble ions. By LCA, it has been shown that 1) changing K-based activators to Na-based activators increases environmental impact of the alkali-activated foams by 1%–4% in terms of most of the impact categories (taking into account the production stage). However, in terms of impact on abiotic depletion of elements and impact on ozone layer depletion, the increase is relatively more significant (11% and 18%, respectively); 2) replacing some parts of fly ash with metakaolin also results in relatively higher environmental footprint (increase of around 1%–4%, while the impact on abiotic depletion of elements increases by 14%); and finally, 3) firing at 1,000°C contributes significantly to the environmental footprint of alkali-activated foams. In such a case, the footprint increases by around one third, compared to the footprint of alkali-activated foams produced at 70°C. A combination of LCA and leaching/toxicity behavior analysis presents relevant combinations, which can provide information about long-term environmental impact of newly developed waste-based materials.

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Splitting tensile strength of recycled tire steel fiber‐reinforced alkali‐activated slag concrete designed by Taguchi method

Eskandarinia

Esmailzade

Aslani

2022

Structural Concrete

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Despite offering several benefits in terms of environment and economics, few studies were conducted on the ground granulated blast furnace slag (GGBFS) based alkali-activated concrete reinforced with recycled tire steel fibers (RTSFs). Therefore, this paper employed the Taguchi method to investigate and optimize the influence of GGBFS content, the alkaline solution to GGBFS content ratio, sodium hydroxide solution concentration, and RTSF volume fraction on splitting tensile strength (STS) of recycled tire steel fiberreinforced alkali-activated slag concrete (RTSFR-AASC). The microstructural evaluation was done through scanning electron microscopy, and Fourier transform infrared spectroscopy (FTIR) analyses. The results indicated that the fiber content, the most efficient parameter on STS, led to a considerable enhancement in the performance characteristic. Microstructural analysis proved the variations in formation of C-S-H gel. The results of the confirmation experiment on the proposed optimized RTSFR-AASC mixture with the highest 28-day STS (7.11 MPa) confirmed the effectiveness of the Taguchi method. K E Y W O R D Sfiber-reinforced alkali-activated concrete, ground granulated blast furnace slag, microstructural analysis, recycled tire steel fiber, splitting tensile strength, Taguchi method

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Analysis of the environmental impacts of alkali-activated concrete produced with waste glass-derived silicate activator – A LCA study

Cited by 73 publications

References 40 publications

Bio‐derived sodium silicate for the manufacture of alkali‐activated binders: Use of bamboo leaf ash as silicate source

Bio‐derived sodium silicate for the manufacture of alkali‐activated binders: Use of bamboo leaf ash as silicate source

Environmental and Biological Impact of Fly Ash and Metakaolin-Based Alkali-Activated Foams Obtained at 70°C and Fired at 1,000°C

Splitting tensile strength of recycled tire steel fiber‐reinforced alkali‐activated slag concrete designed by Taguchi method

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