Effect of microbes addition on the properties and surface morphology of fly ash-based geopolymer paste

Wulandari, Kiki Dwi; Ekaputri, Januarti Jaya; Triwulan,; Kurniawan, Setyo Budi; Primaningtyas, Widya Emilia; Abdullah, Siti Rozaimah Sheikh; Ismail, Nur ‘Izzati; Imron, Muhammad Fauzul

doi:10.1016/j.jobe.2020.101596

Cited by 19 publications

(8 citation statements)

References 38 publications

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“…Moving forward, it is recommended to widen the scope of the optimization studies to determine the most optimal conditions for microbial viability and to obtain even higher healing efficiencies that were already attained in past research [17,18]. Other researchers can look at using other microorganisms, immobilizing materials, geopolymer precursors, and mix ratios.…”

Section: Discussionmentioning

confidence: 99%

Self-Healing Biogeopolymers Using Biochar-Immobilized Spores of Pure- and Co-Cultures of Bacteria

et al. 2020

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A sustainable solution for crack maintenance in geopolymers is necessary if they are to be the future of modern green construction. This study aims to develop self-healing biogeopolymers that could potentially rival bioconcrete. First, a suitable healing agent was selected from Bacillus subtilis, Bacillus sphaericus, and Bacillus megaterium by directly adding their spores in the geopolymers and subsequently exposing them to a precipitation medium for 14 days. Scanning electron microscope with energy-dispersive X-ray (SEM-EDX) analysis revealed the formation of mineral phases for B. subtilis and B. sphaericus. Next, the effect of biochar-immobilization and co-culturing (B. sphaericus and B. thuringiensis) on the healing efficiencies of the geopolymers were tested and optimized by measuring their ultrasonic pulse velocities weekly over a 28-day healing period. The results show that using co-cultured bacteria significantly improved the observed efficiencies, while biochar-immobilization had a weak effect, but yielded an optimum response between 0.3–0.4 g/mL. The maximum crack width sealed was 0.65 mm. Through SEM-EDX and FTIR analyses, the precipitates in the cracks were identified to be mainly CaCO3. With that, there is potential in developing self-healing biogeopolymers using biochar-immobilized spores of bacterial cultures.

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Section: Discussionmentioning

confidence: 99%

Self-Healing Biogeopolymers Using Biochar-Immobilized Spores of Pure- and Co-Cultures of Bacteria

et al. 2020

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“…Moving forward, it is recommended to widen the scope of the optimization studies to determine the most optimal conditions for microbial viability and to obtain even higher healing efficiencies that were already attained in past research [17,18]. Other researchers can look at the use of other microorganisms, immobilizing materials, geopolymer precursors, and mix ratios.…”

Section: Discussionmentioning

confidence: 99%

Self-Healing Biogeopolymers Using Biochar-Immobilized Spores of Pure- and Co-Cultures of Bacteria

Doctolero¹,

Beltran²,

Uba³

et al. 2020

Preprint

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A sustainable solution for crack maintenance in geopolymers is necessary if they are to be the future of modern green construction. This study thus aimed to develop self-healing biogeopolymers that could potentially rival bioconcrete. First, a suitable healing agent was selected from Bacillus subtilis, B. sphaericus, and B. megaterium by directly adding their spores in the geopolymers and subsequently exposing them to a large amount of nutrients for 14 days. SEM-EDX analysis revealed the formation of biominerals for B. subtilis and B. sphaericus. Next, the effect of biochar-immobilization and co-culturing (B. sphaericus and B. thuringiensis) on the healing efficiencies of the geopolymers were tested and optimized by measuring their ultrasonic pulse velocities weekly over a 28-day healing period. The results show that using co-cultured bacteria significantly improved the observed efficiencies, while biochar-immobilization had a weak effect but yielded an optimum response between 0.3-0.4 g/mL. The maximum crack width sealed was 0.65 mm. Through SEM-EDX and FTIR analyses, the biominerals precipitated in the cracks were identified to be mainly CaCO3. Furthermore, image analysis of the XCT scans of some of the healed geopolymers confirmed that their pulse velocities were indeed improving due to the filling of their internal spaces with biominerals. With that, there is potential in developing self-healing biogeopolymers using biochar-immobilized spores of bacterial cultures.

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“…Thus, to tackle these problems of FA and any other waste materials, efforts have been made towards re-use of them in an efficient and green way; for instance, high volumes of FA have been used to replace Portland cement in different types of concrete and cementitious composites [40][41][42][43][44][45][46][47]. More recently, FA has been utilized as an alternative source to make geopolymer paste [48,49], mortar [50,51], and concrete [52][53][54].…”

Section: Introductionmentioning

confidence: 99%

Compressive Strength of Sustainable Geopolymer Concrete Composites: A State-of-the-Art Review

et al. 2021

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The building industry, which emits a significant quantity of greenhouse gases, is under tremendous pressure due to global climate change and its consequences for communities. Given the environmental issues associated with cement production, geopolymer concrete has emerged as a sustainable construction material. Geopolymer concrete is an eco-friendly construction material that uses industrial or agricultural by-product ashes as the principal binder instead of Portland cement. Fly ash, ground granulated blast furnace slag, rice husk ash, metakaolin, and palm oil fuel ash were all employed as binders in geopolymer concrete, with fly ash being the most frequent. The most important engineering property for all types of concrete composites, including geopolymer concrete, is the compressive strength. It is influenced by different parameters such as the chemical composition of the binder materials, alkaline liquid to binder ratio, extra water content, superplasticizers dosages, binder content, fine and coarse aggregate content, sodium hydroxide and sodium silicate content, the ratio of sodium silicate to sodium hydroxide, the concentration of sodium hydroxide (molarity), curing temperature, curing durations inside oven, and specimen ages. In order to demonstrate the effects of these varied parameters on the compressive strength of the fly ash-based geopolymer concrete, a comprehensive dataset of 800 samples was gathered and analyzed. According to the findings, the curing temperature, sodium silicate content, and alkaline solution to binder ratio are the most significant independent parameters influencing the compressive strength of the fly ash-based geopolymer concrete (FA-BGPC) composites.

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Effect of microbes addition on the properties and surface morphology of fly ash-based geopolymer paste

Cited by 19 publications

References 38 publications

Self-Healing Biogeopolymers Using Biochar-Immobilized Spores of Pure- and Co-Cultures of Bacteria

Self-Healing Biogeopolymers Using Biochar-Immobilized Spores of Pure- and Co-Cultures of Bacteria

Self-Healing Biogeopolymers Using Biochar-Immobilized Spores of Pure- and Co-Cultures of Bacteria

Compressive Strength of Sustainable Geopolymer Concrete Composites: A State-of-the-Art Review

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