The Effects of Nanosilica on Mechanical Properties and Fracture Toughness of Geopolymer Cement

Sodium silicate is a commonly used activator in geopolymer that is produced commercially. In this study, rice husk ash (RHA) from agricultural waste was used to synthesize sodium silicate as an activator for geopolymer cement. This white ash was applied for producing sodium silicate with different molarities (8, 10, and 12) and then used to synthesize fly ash-based geopolymer cement. Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) were applied to investigate the micro-characteristics of the geopolymerization products. Bulk density, water absorption, compressive strength, flexural strength, and fracture toughness were carried out to measure and evaluate the geopolymers with sodium silicate. The combination of 10 M NaOH with sodium silicate increased the compressive strength by 16.21% and the flexural strength and fracture toughness by 81.6%. However, sodium silicate combined with 12 M NaOH decreased compressive strengths by 13.23% and flexural strength and fracture toughness by 61.94%. The lowest water absorption value of 12.3% was obtained in a geopolymer paste using sodium silicate combined with 10 M NaOH, and the largest was 13.3% for sodium silicate combined with 8 M NaOH. The microstructure analysis showed the hydrated calcium alumina silicate gel (C–A–S–H) and the SEM image also revealed a compact geopolymer matrix. Thus, it can be concluded that sodium silicate from rice husk ash can be utilized as an activator or reactive material to produce geopolymer cement with a good geopolymer network.

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“… The setup of tools for the three-point bending test: ( a ) setup specimens and ( b ) schematic three bending test [ 15 ] with permission. …”

Section: Figurementioning

confidence: 99%

Sodium Silicate from Rice Husk Ash and Their Effects as Geopolymer Cement

et al. 2022

Self Cite

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“…The solution is to reuse or include solid waste byproducts including fly ash, silica fume, bottom ash, slag, and glass waste into the concrete manufacturing process [1][2][3][4]. These concrete advances diminish the negative impacts of the concrete industry in affordable and natural issues by providing low costs, high strength properties, and ecological amicability [5][6][7]. Currently, the usage of reused aggregate concrete, which is made from waste concrete brought in from building sites and demolition, is being promoted to help alleviate the global scarcity of regular aggregate.…”

Section: Introductionmentioning

confidence: 99%

Concrete with Partial Substitution of Waste Glass and Recycled Concrete Aggregate

et al. 2022

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The current practice of concrete is thought to be unsuitable because it consumes large amounts of cement, sand, and aggregate, which causes depletion of natural resources. In this study, a step towards sustainable concrete was made by utilizing recycled concrete aggregate (RCA) as a coarse aggregate. However, researchers show that RCA causes a decrease in the performance of concrete due to porous nature. In this study, waste glass (WG) was used as a filler material that filled the voids between RCA to offset its negative impact on concrete performance. The substitution ratio of WG was 10, 20, or 30% by weight of cement, and RCA was 20, 40, and 60% by weight of coarse aggregate. The slump cone test was used to assess the fresh property, while compressive, split tensile, and punching strength were used to assess the mechanical performance. Test results indicated that the workability of concrete decreased with substitution of WG and RCA while mechanical performance improved up to a certain limit and then decreased due to lack of workability. Furthermore, a statical tool response surface methodology was used to predict various strength properties and optimization of RCA and WG.

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“…Geopolymer is a new type of cementitious material with a three-dimensional network structure prepared from natural or artificial silicon-alumina materials as raw materials through polymerization such as strong alkali action and lattice reconstruction [9,10]. In recent years, scholars from various countries have devoted themselves to the use of low-cost industrial and agricultural solid wastes in the preparation of geopolymers, which can effectively reduce cement consumption [11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Unconfined Compression Strength and Microstructure Characteristics of Slag and Fly Ash-Based Geopolymer Stabilized Riverside Soft Soil

Luo

Zhao

et al. 2022

Polymers

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To solve the issues of insufficient early strength of cement stabilized soil and high resource cost, high reduction cost, and high environmental cost induced by the application of cement, the slag and fly ash-based geopolymer was adopted as the stabilizer to treat riverside soft soil. This study mainly investigated the effects of stabilizer content, slag-to-fly ash ratio, and alkaline activator content on the strength of geopolymer stabilized soils with different curing ages. Unconfined compressive strength (UCS), scanning electron microscope (SEM), and X-ray energy spectrum analysis (EDS) tests were carried out. The results show that the stabilizer content, slag–fly ash ratio, and alkaline activator content have a decisive influence on the UCS of geopolymer-stabilized soil. The mix-proportions scheme of geopolymer stabilized riverside soft soil, with a geopolymer content of 15%, a slag–fly ash ratio of 80:20, and an alkaline activator content of 30%, is considered optimum. It is proven by SEM that the uniformly distributed gelatinous products formed in the geopolymer-stabilized soil bind the soil particles tightly. Moreover, the EDS analysis confirms that the gelatinous products are mainly composed of C-S-H gel and sodium-based aluminosilicate (N-A-S-H).

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The Effects of Nanosilica on Mechanical Properties and Fracture Toughness of Geopolymer Cement

Cited by 45 publications

References 50 publications

Sodium Silicate from Rice Husk Ash and Their Effects as Geopolymer Cement

Sodium Silicate from Rice Husk Ash and Their Effects as Geopolymer Cement

Concrete with Partial Substitution of Waste Glass and Recycled Concrete Aggregate

Experimental Investigation of Unconfined Compression Strength and Microstructure Characteristics of Slag and Fly Ash-Based Geopolymer Stabilized Riverside Soft Soil

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