Strength, porosity and life cycle analysis of geopolymer and hybrid cement mortars for sustainable construction

Raza, Muhammad Huzaifa; Khan, Mahram; Zhong, Ray Y.

doi:10.1016/j.scitotenv.2023.167839

Cited by 25 publications

(3 citation statements)

References 63 publications

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“…On the other hand, it demonstrates how the compressive strengths are strongly influenced by the physical properties, with higher strengths related to a higher density and lower porosity and water absorption [52,53].…”

Section: Physical Testsmentioning

confidence: 99%

Compositional Differences in Construction and Demolition Wastes (CDWs) for Geopolymer Mortars: A Comparative Study Using Different Precursors and Alkaline Reagents

Volpintesta,

Finocchiaro,

Barone

et al. 2024

Minerals

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In the view of the recycling and upscaling processes of waste materials, three different precursors, namely metakaolin, fly ash and volcanic ash, were mixed with Na- or K-silicate to produce binders aimed for the synthesis of geopolymer mortars based on construction and demolition wastes (CDWs). These later, used as aggregates in amount of 50 wt.%, were sampled in two geologically different Italian areas. A comparative study was carried out through a multidisciplinary approach using mineralogical–chemical analyses and physical–mechanical tests for the characterization of six binders and twelve mortars. The aim was to verify the effects of CDW interactions on binders as well as the extent of their compositional influences on the final properties. The chemical and mineralogical results evidenced strong compositional differences among the CDWs, differently influencing the physical–mechanical performances (i.e., compressive strength, density, water absorption and porosity) of the mortar samples. Regardless of the types of precursors and CDWs used, a better influence of K-silicate than sodium on the synthetised samples was observed. Furthermore, the higher versatility of metakaolin mortars with any type of CDW used was noted. Contrary, fly ash and volcanic ash mortars showed better properties with CDWs based on their high silica content and volcanic minerals. The study highlighted the critical roles of the CDW composition and precursor selection in mortar production. It confirmed that CDWs can be recycled for geopolymeric synthesis through proper characterisation and binder selection. Optimising these parameters allows for the successful integration of CDWs into geopolymeric materials. This process supports the advancement of a circular economy in the construction industry.

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Section: Physical Testsmentioning

confidence: 99%

Compositional Differences in Construction and Demolition Wastes (CDWs) for Geopolymer Mortars: A Comparative Study Using Different Precursors and Alkaline Reagents

Volpintesta,

Finocchiaro,

Barone

et al. 2024

Minerals

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“…Gopalakrishna et al [25] exposed that the geopolymer binder has significantly lower values of embodied energy and global warming potential compared to the OPC-based mortar, with reductions of 94% and 97%, respectively. In contrast, despite the favorable characteristics of geopolymer binders, Raza et al [26] found that while hybrid cement mortars outperformed geopolymers in most impact categories in a life cycle analysis, the overall environmental impact assessment using the 'coefficient of performance' indicated that hybrid cement mortars have a significantly lower environmental burden than geopolymers. Gopalakrishna et al [27] conducted both durability performance and LCA analysis for the German specifications of geopolymer concretes based on recycled aggregate, fly ash and GGBFS and concluded that the recycled aggregate geopolymer concretes had an embodied energy of 4.48% and a global warming potential of 0.083, both markedly lower than conventional concrete.…”

Section: Introductionmentioning

confidence: 99%

Evaluating Techno-Eco-Efficiency of Waste Clay Brick Powder (WCBP) in Geopolymer Binders

Sharmin,

Biswas,

Sarker

2024

Buildings

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The global focus on geopolymer binder production has increased due to the adoption of waste materials and industrial byproducts. Given the gradual decline in the availability of fly ash and ground granular blast furnace slag (GGBFS) resulting from the decarbonization process in electricity and steel production, waste clay brick powder (WCBP) could be a viable substitute for these pozzolanic by-products. This study presents the economic and environmental benefits of the use of WCBP as a replacement for conventional pozzolanic by-products in geopolymer binder production by assessing its techno-eco-efficiency, environmental impact, and cost-effectiveness performances. The favorable mechanical characteristics exhibited by the fly ash–GGBFS–WCBP-based geopolymer binder emphasize the importance of assessing its sustainability alongside its technical viability. The study employed life cycle analysis (LCA), following ISO framework, and using the Simapro software 9.2, to evaluate the environmental implications of the use of WCBP-based geopolymer mixtures. Human toxicity emerged as the primary impact. Moreover, the analysis of life cycle costs highlighted key financial factors, with around 65–70% attributed to alkaline activators of the total cost. The production of alkaline activators was identified as a critical point for both environmental impact and economic considerations due to energy consumption. While WCBP-rich samples exhibit a 1.7–0.7% higher environmental impact compared to the control mix (CM), their high mechanical strength and cost-effectiveness make them technologically and economically efficient geopolymer mixes. In conclusion, the portfolio analysis for techno-eco-efficiency affirms that mixes containing 40%, 30%, and 20% WCBP are more efficient than those using 10% and 0% WCBP, respectively.

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“…Additionally, several authors have investigated the integration of natural fibers into cement to enhance its mechanical properties [13][14][15]. Recognizing cement's critical role in construction, substantial efforts have been made to develop more sustainable cements [16,17] or alternative materials for replacement. Many researchers are focused on replacing a portion of cement with supplementary cementitious materials to decrease hazardous emissions [18,19].…”

Section: Introductionmentioning

confidence: 99%

A Sustainable Approach Using Beef and Pig Bone Waste as a Cement Replacement to Produce Concrete

Palomino-Guzmán,

González-López,

Olmedo-Montoya

et al. 2024

Sustainability

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Owing to the ongoing accumulation of industrial by-products, the management and disposal of waste have emerged as a significant issue. Employing these industrial wastes as an alternative to replace cement holds potential as a promising solution for conserving energy and reducing CO2 emissions. In this study, pig and beef bone powder were used as cement replacements in concrete, and the mechanical properties were studied. Bone powders were prepared from random bones collected from local slaughterhouses, butchers, and restaurants. The pig bone powder (PBP) and beef bone powder (BBP) were prepared by direct fire contact, oven-calcined for 4 h at 300 °C, crushed, and sieved to size 0.4 to 2 mm. A concrete mix design was formulated for a target compressive strength of 21 MPa at 28 days of curing. This design included three different levels of cement replacement with each type of bone powder (10%, 15%, and 20% by mass). These mixes were then evaluated and compared to a control mix without any bone powder replacement (PB-0). This study evaluated the mechanical properties via compressive strength and flexural testing. The results showed that the workability of the mixtures decreased with the increase in bone powder content. Bone powder functions as a pozzolanic substance, engaging in a chemical reaction with the calcium hydroxide in concrete to produce compounds that exhibit cement-like properties; however, an increase in bone powder content worsened the mechanical properties. The most promising results were obtained for a 10% replacement percentage of BBP and PBP, obtaining strengths of 21.15 MPa and 22.78 MPa, respectively. These are both above the design strength, with PBP concrete even exceeding the strength of PB-0 (21.75 MPa). These results showed a good agreement with the standard values and allow to use these wastes as a replacement for cement, becoming a sustainable solution to the exploitation of quarry materials and, in turn, to the problem of contamination by biological waste from the meat industry.

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Strength, porosity and life cycle analysis of geopolymer and hybrid cement mortars for sustainable construction

Cited by 25 publications

References 63 publications

Compositional Differences in Construction and Demolition Wastes (CDWs) for Geopolymer Mortars: A Comparative Study Using Different Precursors and Alkaline Reagents

Compositional Differences in Construction and Demolition Wastes (CDWs) for Geopolymer Mortars: A Comparative Study Using Different Precursors and Alkaline Reagents

Evaluating Techno-Eco-Efficiency of Waste Clay Brick Powder (WCBP) in Geopolymer Binders

A Sustainable Approach Using Beef and Pig Bone Waste as a Cement Replacement to Produce Concrete

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