Modeling and optimization of fly ash–slag-based geopolymer using response surface method and its application in soft soil stabilization

Chen, Keyu; Wu, Dazhi; Zhang, Zilong; Pan, Chonggen; Shen, Xiao‐Jun; Xia, Linling; Zang, Jiawei

doi:10.1016/j.conbuildmat.2021.125723

Cited by 68 publications

(19 citation statements)

References 53 publications

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“…However, compared to normally alkali-activated FA/ground granulated blast furnace slag (GGBFS)-based geopolymer, this compressive strength seems much lower. For example, Chen et al [ 70 ] optimized the alkali-activated FA/slag-based geopolymer by response surface method. The 3d and 28 d compressive strengths were 28.10 MPa and 54.69 MPa, respectively.…”

Section: Resultsmentioning

confidence: 99%

Utilization of Calcium Carbide Residue as Solid Alkali for Preparing Fly Ash-Based Geopolymers: Dependence of Compressive Strength and Microstructure on Calcium Carbide Residue, Water Content and Curing Temperature

Wang

Guo

et al. 2022

Materials

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Calcium carbide residue (CCR) is a solid waste resulting from acetylene gas production. In this study, CCR was used as an alkali activator to prepare fly ash (FA)-based geopolymers without any alkali supplementation. We studied the factors (FA/CCR ratio, curing temperature, and water/binder ratio) influencing the mechanical property of FA/CCR-based geopolymers. The compressive strength results showed that, by optimizing these three factors, the FA/CCR mixture has great potential for use as a cementitious material and geopolymer with a dense microstructure having a maximal compressive strength of 17.5 MPa. The geopolymers’ chemical structure, microstructure, and chemical composition were characterized and determined by a combination of techniques. All these results revealed that amorphous C-(A)-S-H (calcium (aluminate) silicate hydrate) gels mainly formed after geopolymerization resulting from the reaction of FA and CCR. In addition, some crystallines, such as ettringite and monosulfate, were also formed. Further, geopolymers prepared with a suitable FA/CCR ratio (1:1 or 1:2) possessed a compact microstructure because of their sufficient reactive SiO2 and Al2O3 and high-enough alkalinity, responsible for higher content of C-(A)-S-H formation and better mechanical property. Too high curing temperature or water content induced the formation of a loosely bound geopolymer matrix that strongly weakens its mechanical property.

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Section: Resultsmentioning

confidence: 99%

Utilization of Calcium Carbide Residue as Solid Alkali for Preparing Fly Ash-Based Geopolymers: Dependence of Compressive Strength and Microstructure on Calcium Carbide Residue, Water Content and Curing Temperature

Wang

Guo

et al. 2022

Materials

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“…In addition, the strength of II-1 is 1.36 times that of C-2. The results show that cement and geopolymer are used as the stabilizer for stabilizing soft soil, which has significantly improved the mechanical properties of the soil [38][39][40][41][42][43][44]48]. It is worth noting that the geopolymer has a better stabilizing effect on the riverside soft soil, which may be attributed to the pozzolanic reaction in the geopolymer soil [49].…”

Section: Effect Of the Type And Content Of Stabilizer On The Ucs Of S...mentioning

confidence: 91%

“…In this study, the soft-soil stabilizers used included P•O 42.5 cement (Hunan Southern Cement Group Co., Ltd., Changsha, China) and slag and fly ash-based geopolymer. S95-grade slag (Gongyi Longze Water Purification Material Co., Ltd., Zhengzhou, China) and F low-calcium fly ash (Gongyi Yuanheng Water Purification Material Factory, Zhengzhou, China) were used as raw materials of geopolymer, which conform to the Chinese standard GB/T 27690-2011 [43,44]. Figure 1 shows the appearance of cement, slag, and fly ash, and their specific surface areas are 342, 505, and 935 m 2 /kg, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The EDS analysis result of Figure 7c shows that the geopolymer gel (point c) is composed of hydrated calcium silicate (C-S-H) and sodium-based aluminosilicate (N-A-S-H). The N-A-S-H gel is mainly formed by the "dissolution-polymerization" reaction of active substances such as Si and Al in the alkali-fly ash system [44,50,52]. As shown in Figure 7d, the internal particles of the geopolymer soil sample at 28 d are fully bonded and consolidated to form a whole.…”

Section: Microstructure Characteristics Of Stabilized Soilmentioning

confidence: 99%

“…Arulrajah et al [38][39][40][41][42][43] found that the stabilizer content, geopolymer ingredients, component quantities, and curing age significantly affected the strength formation of the treated soil. Chen [44] evaluated the compressive strength of slag-fly ash-based geopolymer stabilized soil with different stabilizer content (8-14%), moisture content (30-60%), and curing age (0-28 d). The results show that the strength reaches the maximum value of 527.09 kPa when 14% geopolymer is added.…”

Section: Introductionmentioning

confidence: 99%

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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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Combined utilization of slag, fly ash, and polyacrylamide for sustainable saline soil improvement: a win-win strategy

Zhao,

Lu,

Zhang

et al. 2024

Bull Eng Geol Environ

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Modeling and optimization of fly ash–slag-based geopolymer using response surface method and its application in soft soil stabilization

Cited by 68 publications

References 53 publications

Utilization of Calcium Carbide Residue as Solid Alkali for Preparing Fly Ash-Based Geopolymers: Dependence of Compressive Strength and Microstructure on Calcium Carbide Residue, Water Content and Curing Temperature

Utilization of Calcium Carbide Residue as Solid Alkali for Preparing Fly Ash-Based Geopolymers: Dependence of Compressive Strength and Microstructure on Calcium Carbide Residue, Water Content and Curing Temperature

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

Combined utilization of slag, fly ash, and polyacrylamide for sustainable saline soil improvement: a win-win strategy

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