Calcium-free geopolymer as a stabilizer for sulfate-rich soils

Zhang, Mo; Zhao, Mengxuan; Zhang, Guoping; Nowak, Peter; Coen, Adam; Tao, Mingjiang

doi:10.1016/j.clay.2015.02.029

Cited by 101 publications

(39 citation statements)

References 36 publications

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“…The trends of the variation of Young's modulus with Si/Al and Na/Al ratios are similar to those of UCS. The sustainably synthesized geopolymers from this study have adequate strength to be utilized as a sustainable road base material [43] and in soil stabilization [18]. The influence of L/S ratios on the UCS was studied using FA:RM ratio of 8:2 with L/S ranging from 0.35 to 0.6 w/w and the strength results are presented in Figure 7.…”

Section: Parametric Influences On Mechanical Propertiesmentioning

confidence: 99%

“…From Figure 5d, it is noted that even at 28 days of curing, the strength shows an upward trend without reaching a plateau indicating that complete curing has not been achieved, and hence, a prolonged curing beyond 28 days would further improve the strength and stiffness. This gradual strength development could be due to the presence of lime in the mixture (i.e., 3.9, 5.3, and 6.7% for FA4, FA6, and FA8, respectively), thereby requiring prolonged curing [18]. Figure 6 shows the influence of initial Si/Al and Na/Al ratios in the final strength of the activated end products.…”

Section: Parametric Influences On Mechanical Propertiesmentioning

confidence: 99%

“…Aluminosilicate gels form geopolymers and nanocrystalline zeolites which have comparable strength properties, making them a potential replacement for ordinary Portland cement [7]. They have been synthesized using aluminosilicates and an alkali activator solution such as Na 2 SiO 3 , NaOH, and environmental engineering, such as in cement [11,12], foamed panels [13], heavy metal immobilization [14], masonry units [15,16], paving blocks [17], and soil stabilization [18]. Several studies have been conducted by synthesizing these, using different precursors such as metakaolin [11,12,[19][20][21] and industrial byproducts such as coal fly ash [22][23][24], coal gangue [25,26], slags [22], municipal solid waste incinerator fly ash [27], recycled asphalt pavement [28], red mud [21,24,29], rice husk ash [6,11], waste glass [16], and water treatment sludge [15].…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Properties of Geopolymers Synthesized from Fly Ash and Red Mud under Ambient Conditions

Koshy

Dondrob

et al. 2019

Crystals

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Aluminosilicate gels form geopolymers and nanocrystalline zeolites which have comparable strength properties, making them a potential replacement for ordinary Portland cement. The study explores the use of two untreated industrial wastes, Class-F fly ash and red mud, for synthesizing geopolymeric material at ambient synthesis conditions. The high alkalinity present in the red mud was exploited for the dissolution of silica in the fly ash and red mud. The mechanical, mineralogical, microstructural, and pore characteristics were analyzed and the contributions of curing period, Si/Al, Na/Al, and liquid-to-solid (L/S) ratios on the compressive strength of the end products were also investigated. The alkalinity of the system due to the red mud was adequate for the dissolution of raw fly ash and the subsequent formation of aluminosilicate gels. The strength of the end product was directly proportional to the initial Si/Al ratio and the specimens with highest fly ash content exhibited highest compressive strength values after 28 days of curing. Furthermore, fly ash contributed to the formation and distribution of interstitial and capillary pores in the aluminosilicate matrix. The lowest L/S ratio of the initial mix resulted in the end product with the highest unconfined compressive strength.

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Section: Parametric Influences On Mechanical Propertiesmentioning

confidence: 99%

Section: Parametric Influences On Mechanical Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mechanical Properties of Geopolymers Synthesized from Fly Ash and Red Mud under Ambient Conditions

Koshy

Dondrob

et al. 2019

Crystals

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“…Most available research and industrial applications on geopolymers are limited to steamed or dry heat-cured concrete [12], whereas for ground improvement, elevated heat is not practically possible. Therefore, soil stabilization by geopolymers has only been investigated at ambient temperature [2], [13], [14]. In fact, low temperature maintains slow rate of geopolymerisation and strength gain in stabilized soils.…”

Section: Introductionmentioning

confidence: 99%

Stabilisation of Clay with Fly-Ash Geopolymer Incorporating GGBFS

Abdullah¹,

Shahin²,

Sarker³

2017

World Congress on Civil, Structural, and Environmental Engineering

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-Low water/binder ratio and higher activator content can help to accelerate the setting and strength development of fly-ash geopolymers cured at ambient condition. This study aims to achieve clay stabilization with fly-ash based geopolymer incorporating ground granulated blast-furnace slag (GGBFS), to enhance soil strength performance at ambient temperature. Laboratory experiments were performed on clay samples stabilized with both slag and fly-ash geopolymer and ordinary Portland cement (OPC), including the soil plasticity, compaction and unconfined compressive strength. The investigation was expanded to include un-activated fly-ash/slag clay samples used as control mixtures. The results indicated that introducing GGBFS to class (F) fly-ash based geopolymer assists, when synthesised in certain concentrations, in achieving a setting time and compressive strength comparable to OPC stabilised clay.

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“…The chemical compositions of the fly-ash and slag used are given in Table 2. The alkaline activator used in the current study to synthesize the geopolymer was prepared from Grade (D) sodium silicate and sodium hydroxide, both in solution form, as recommended by several researchers [e.g., 7,8,18,[19][20][21][22]. The sodium silicate solution was supplied by PQ Australia and contains the following mass ratios: Na2O = 14.7% and SiO2/Na2O = 2.…”

Section: Methodsmentioning

confidence: 99%

Strength Characteristics of Clay Stabilized with Fly-ash Based Geopolymer Incorporating Granulated Slag

Abdullah¹,

Shahin²

2019

World Congress on Civil, Structural, and Environmental Engineering

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The use of traditional binders (e.g., lime or cement) in soil stabilization faces many obstacles of environmental nature, and geopolymers have been recently become an attractive alternative binder that may overpasses such obstacles. However, the literature lacks detailed information in relation to the geo-mechanical characteristics of geopolymer-stabilized soils and this paper fills in part of this gap. The paper presents an evaluation of the stress-strain behavior of two natural clays of different mineralogy treated with fly-ash based geopolymer. Laboratory experiments were performed including the Unconfined Compressive Strength (UCS) tests and Consolidated Undrained (CU) triaxial tests under different confining pressures. The results indicate that the addition of geopolymer increases the strength and stiffness of clay, which contributes to higher uniaxial and triaxial peak stresses. The confining pressure was found to have a considerable influence on the stress-strain behavior and excess pore-water pressure obtained from the CU tests. The results also demonstrate that clay mineralogy is an important factor that affects the stress-strain performance of geopolymer-treated clay.

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Calcium-free geopolymer as a stabilizer for sulfate-rich soils

Cited by 101 publications

References 36 publications

Mechanical Properties of Geopolymers Synthesized from Fly Ash and Red Mud under Ambient Conditions

Mechanical Properties of Geopolymers Synthesized from Fly Ash and Red Mud under Ambient Conditions

Stabilisation of Clay with Fly-Ash Geopolymer Incorporating GGBFS

Strength Characteristics of Clay Stabilized with Fly-ash Based Geopolymer Incorporating Granulated Slag

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