Browsing by Author "Ozbakkaloglu, T."

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Performance assessment and economic and ecological analysis of carbon-negative recycled crumb rubber-based geopolymers
(Elsevier Ltd, 2024) Sarkaz, A.M.H.; Danish, A.; Memiş, S.; Yaprak, H.; Gencel, O.; Ozbakkaloglu, T.
Geopolymer technology offers several compelling ecological and economic advantages regarding waste management. This research investigates the effect of size (less than equal to 4 mm) and amount (5–15 vol%) of crumb rubber (CR) as fine aggregate on the physical, mechanical, and durability properties of geopolymers. The economic and ecological analyses were also performed to determine the effect of producing CR-based geopolymers on cost and the environment. The results revealed that the addition of CR negatively influences the physical, mechanical, and durability properties; nonetheless, incorporation of 5–10 vol% CR with a size less than 2 mm exhibited satisfactory performance fit for medium-strength structures such as foundations, partition walls, sidewalks, drainage structures, etc. Additionally, although the incorporation of CR slightly increases the production cost (3.99–11.97%) and embodied energy (0.08–0.24%) of resulting geopolymers, the embodied CO2 emission of 5, 10, and 15 vol% CR-incorporated geopolymer mixes is 90.4, −143.6 and −377.6 kgCO2e/m3, respectively. In contrast, the embodied CO2 emissions of conventional geopolymer mix is 324.4 kgCO2e/m3, which shows the negative carbon emission potential of CR-modified geopolymers, providing a glimmer of hope for sustainable development in the construction industry.
Performance assessment and economic and ecological analysis of carbon-negative recycled crumb rubber-based geopolymers
(2024.01.01) Sarkaz, A.M.H.; Danish, A.; Memis, S.; Yaprak, H.; Gencel, O.; Ozbakkaloglu, T.
Geopolymer technology offers several compelling ecological and economic advantages regarding waste management. This research investigates the effect of size (less than equal to 4 mm) and amount (5-15 vol%) of crumb rubber (CR) as fine aggregate on the physical, mechanical, and durability properties of geopolymers. The economic and ecological analyses were also performed to determine the effect of producing CR-based geopolymers on cost and the environment. The results revealed that the addition of CR negatively influences the physical, mechanical, and durability properties; nonetheless, incorporation of 5-10 vol% CR with a size less than 2 mm exhibited satisfactory performance fit for medium-strength structures such as foundations, partition walls, sidewalks, drainage structures, etc. Additionally, although the incorporation of CR slightly increases the pro-duction cost (3.99-11.97%) and embodied energy (0.08-0.24%) of resulting geopolymers, the embodied CO2 emission of 5, 10, and 15 vol% CR-incorporated geopolymer mixes is 90.4,-143.6 and-377.6 kgCO2e/m3, respectively. In contrast, the embodied CO2 emissions of conventional geopolymer mix is 324.4 kgCO2e/m3, which shows the negative carbon emission potential of CR-modified geopolymers, providing a glimmer of hope for sustainable development in the construction industry.
Performance assessment of fiber-reinforced coral aggregate-based lightweight foam concrete for sustainable marine construction
(2024.01.01) Bayraktar, O.Y.; Danish, A.; Bodur, B.; Kaplan, G.; Aydin, A.C.; Ozbakkaloglu, T.
Based on the storage of raw materials and the high energy consumption associated with marine transportation, using coral aggregates to produce cementitious composites is the most promising candidate to counter these challenges. This research evaluates the suitability of coral aggregate and polypropylene fibers (PPF) to produce lightweight foam concrete. Quartz aggregate was replaced with coral aggregate in percentages of 25, 50, and 100 % along with 0-3 % incorporation of PPF. The performance assessment (through physical, mechanical, and durability tests) and economic and ecological analysis were conducted on the concrete mixtures. Based on the properties assessed, the optimal percentages of coral aggregate in specimens containing 0 %, 1.5 %, and 3 % PPF are 50 %, 50 %, and 100 %, respectively. This research may serve as a guide for future studies, focusing on coral aggregates as an effective alternative to conventional aggregates in cementitious composite production, with the goal of promoting their commercial applications for resource conservation.
Performance evaluation and cost analysis of ternary blended geopolymers for sustainable built environment under different curing regimes
(Elsevier Ltd, 2023) Alnkaa, A.A.; Danish, A.; Yaprak, H.; Memis, S.; Gencel, O.; Amran, M.; Ozbakkaloglu, T.
Geopolymer technology provides ecological and monetary benefits in supporting waste management. This study examines the influence of different aluminosilicate materials (85–100 % ground granulated blast furnace slag (GGBS), 0–15 % fly ash (FA), and 0–15 % waste glass powder (WGP)) and curing regimes (water and steam curing) on the mechanical and durability properties and production cost of geopolymers. The water-binder ratio, binder-fine aggregate, and alkaline activator-binder ratios were kept constant, whereas different amounts of superplasticizer were used in all the samples to achieve the target strength of 250 mm. The results revealed that the compressive and flexural strengths of specimens containing FA and WGP outperformed those of GGBS-based geopolymers. The compressive and flexural strength results demonstrated that the optimal FA and WGP replacement levels in ternary blended geopolymers were 10 % and 0–15 %, respectively; subsequent increases or decreases in FA and WGP replacement levels in most of the specimens resulted in mechanical properties similar to those of GGBS-based geopolymers without a significant increase in the production cost. Moreover, exposing specimens to freeze–thaw cycles led to higher compressive strength, ultrasonic velocity values, and weight irrespective of the curing regime, which can be credited to the continued geopolymerization reaction. Contrary to freeze–thaw cycles, only some specimens exhibited higher compressive and flexural strength once exposed to magnesium sulfate (MgSO4) solution. Like compressive and flexural strengths, the resistance of ternary blended geopolymers against freeze–thaw and sulfate attack is higher than that of GGBS-based geopolymers. It is also revealed that water- and steam-cured specimens provide better early- and later-age mechanical and durability properties; therefore, the choice of curing regime should be based on potential application. The positive results of this study indicate that ternary blended geopolymers have the potential to solve environmental challenges while also being futuristic and cost-effective in the production of eco-friendly and structural-grade materials.
Performance evaluation and cost analysis of ternary blended geopolymers for sustainable built environment under different curing regimes
(2023.01.01) Alnkaa, A.A.; Danish, A.; Yaprak, H.; Memis, S.; Gencel, O.; Amran, M.; Ozbakkaloglu, T.
Geopolymer technology provides ecological and monetary benefits in supporting waste management. This study examines the influence of different aluminosilicate materials (85-100 % ground granulated blast furnace slag (GGBS), 0-15 % fly ash (FA), and 0-15 % waste glass powder (WGP)) and curing regimes (water and steam curing) on the mechanical and durability properties and production cost of geopolymers. The water-binder ratio, binder-fine aggregate, and alkaline activator-binder ratios were kept constant, whereas different amounts of superplasticizer were used in all the samples to achieve the target strength of 250 mm. The results revealed that the compressive and flexural strengths of specimens containing FA and WGP outperformed those of GGBS-based geopolymers. The compressive and flexural strength results demonstrated that the optimal FA and WGP replacement levels in ternary blended geopolymers were 10 % and 0-15 %, respectively; subsequent increases or decreases in FA and WGP replacement levels in most of the specimens resulted in mechanical properties similar to those of GGBS-based geopolymers without a significant increase in the production cost. Moreover, exposing specimens to freeze-thaw cycles led to higher compressive strength, ultrasonic velocity values, and weight irrespective of the curing regime, which can be credited to the continued geopolymerization reaction. Contrary to freeze-thaw cycles, only some specimens exhibited higher compressive and flexural strength once exposed to magnesium sulfate (MgSO4) solution. Like compressive and flexural strengths, the resistance of ternary blended geopolymers against freeze-thaw and sulfate attack is higher than that of GGBS-based geopolymers. It is also revealed that water-and steam-cured specimens provide better early-and later-age mechanical and durability properties; therefore, the choice of curing regime should be based on potential application. The positive results of this study indicate that ternary blended geopolymers have the potential to solve environmental challenges while also being futuristic and cost-effective in the production of eco-friendly and structural-grade materials.
Performance, cost, and ecological assessment of fiber-reinforced high-performance mortar incorporating pumice powder and ground granulated blast furnace slag as partial cement replacement
(2024.01.01) Ifzaznah, H.H.H.; Güllü, A.; Memis, S.; Yaprak, H.; Gencel, O.; Ozbakkaloglu, T.
The production of cement and concrete is a significant source of greenhouse gas emissions. Hence, recent governmental regulations have brought the attention of industry and academia to the environmental impact of these materials. Recognizing the pressing need to address the environmental footprint of the widely used construction materials, there is a growing focus on strategic initiatives that involve incorporating alternative waste materials to partially substitute ordinary Portland cement (OPC). It is also noteworthy that high-performance concrete and mortar emits significantly less CO2 per unit of strength. Therefore, this study aims to develop high-strength mortar mixes incorporating pumice powder (PP) and ground granulated blast-furnace slag (GGBS) as substitutes for OPC. To this end, nine different mixes, with varying levels of OPC replacement ranging from 0% to 60%, were produced. These mixes underwent a comprehensive experimental evaluation to assess their physical, mechanical, and durability properties. Scanning electron microscopy analyses were conducted to examine the microstructural characteristics of the mixes as well. Furthermore, the embodied energy, embodied carbon, and cost of the prepared mixes were calculated. The experimental findings suggest that high-strength mortar, with a compressive strength varying between 64 and 82 MPa at 28 days of curing, can be successfully produced with reduced embodied carbon and embodied energy compared to conventional mortar mix while maintaining a comparable cost.