Properties of fresh and hardened fly ash/slag based geopolymer concrete: A review

Zhang, Peng; Gao, Zhen; Juan, Wang; Guo, Jinjun; Hu, Shaowei; Ling, Yifeng

doi:10.1016/j.jclepro.2020.122389

Cited by 336 publications

(99 citation statements)

References 111 publications

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“…Keep in mind that the alkalinity and the pH value of NaOH is much higher than water glass; their contributions on the activation and geopolymerization are different; and in turn the influence of setting time is somewhat distinguished. With regard to the mixing water, its impact manner and degree cannot seem to be explained with the dilution effect that is applicable to cement-based materials, even though the polycondensation of geopolymer produces water molecules [ 15 , 17 , 23 , 29 ].…”

Section: Resultsmentioning

confidence: 99%

“…They have been attracting more and more attention worldwide. Today the primary application of geopolymers in civil engineering is the development and production of building materials as a potential alternative to traditional materials with high energy consumption and pollution [ 15 , 16 , 17 , 18 ]. Geopolymers are expected to be green binding material and consume less energy.…”

Section: Introductionmentioning

confidence: 99%

“…Geopolymers/alkali-activated binders have attracted considerable attention as promising construction and repair materials since their discovery because of their superior properties. Moreover, less pollution was caused by geopolymer/alkali-activated concretes than conventional cement concretes [ 17 , 18 ]. However, further research is needed to identify the sustainability and low-carbon nature of geopolymers and related products [ 1 , 3 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

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Protective Geopolymer Coatings Containing Multi-Componential Precursors: Preparation and Basic Properties Characterization

et al. 2020

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This paper presents an experimental investigation on geopolymer coatings (GPC) in terms of surface protection of civil structures. The GPC mixtures were prepared with a quadruple precursor simultaneously containing fly ash (FA), ground granulated blast-furnace slag (GBFS), metakaolin (MK), and Portland cement (OPC). Setting time, compressive along with adhesive strength and permeability, were tested and interpreted from a perspective of potential applications. The preferred GPC with favorable setting time (not shorter than 120 min) and desirable compressive strength (not lower than 35 MPa) was selected from 85 mixture formulations. The results indicate that balancing strength and setting behavior is viable with the aid of the multi-componential precursor and the mixture design based on total molar ratios of key oxides or chemical elements. Adhesive strength of the optimized GPC mixtures was ranged from 1.5 to 3.4 MPa. The induced charge passed based on a rapid test of coated concrete specimens with the preferred GPC was 30% lower than that of the uncoated ones. Setting time of GPC was positively correlated with η[Si/(Na+Al)]. An abrupt increase of setting time occurred when the molar ratio was greater than 1.1. Compressive strength of GPC was positively affected by mass contents of ground granulated blast furnace slag, metakaolin and ordinary Portland cement, and was negatively affected by mass content of fly ash, respectively. Sustained seawater immersion impaired the strength of GPC to a negligible extent. Overall, GPC potentially serves a double purpose of satisfying the usage requirements and achieving a cleaner future.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Protective Geopolymer Coatings Containing Multi-Componential Precursors: Preparation and Basic Properties Characterization

et al. 2020

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“…Currently, many research centers conduct tests on the separate use of SF [ 13 , 14 , 15 , 16 ] and FA [ 17 , 18 , 19 , 20 ] for concrete and studies assessing the properties of composites for which the addition of both materials was used [ 21 , 22 , 23 , 24 ]. Innovative hybrid techniques are increasingly used based on the synergy of interconnected components.…”

Section: Introductionmentioning

confidence: 99%

Studies of Fracture Toughness in Concretes Containing Fly Ash and Silica Fume in the First 28 Days of Curing

Golewski

Gil

2021

Materials

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This paper presents the results of the fracture toughness of concretes containing two mineral additives. During the tests, the method of loading the specimens according to Mode I fracture was used. The research included an evaluation of mechanical parameters of concrete containing noncondensed silica fume (SF) in an amount of 10% and siliceous fly ash (FA) in the following amounts: 0%, 10% and 20%. The experiments were carried out on mature specimens, i.e., after 28 days of curing and specimens at an early age, i.e., after 3 and 7 days of curing. In the course of experiments, the effect of adding SF to the value of the critical stress intensity factor—KIcS in FA concretes in different periods of curing were evaluated. In addition, the basic strength parameters of concrete composites, i.e., compressive strength—fcm and splitting tensile strength—fctm, were measured. A novelty in the presented research is the evaluation of the fracture toughness of concretes with two mineral additives, assessed at an early age. During the tests, the structures of all composites and the nature of macroscopic crack propagation were also assessed. A modern and useful digital image correlation (DIC) technique was used to assess macroscopic cracks. Based on the conducted research, it was found the application of SF to FA concretes contributes to a significant increase in the fracture toughness of these materials at an early age. Moreover, on the basis of the obtained test results, it was found that the values of the critical stress intensity factor of analyzed concretes were convergent qualitatively with their strength parameters. It also has been demonstrated that in the first 28 days of concrete curing, the preferred solution is to replace cement with SF in the amount of 10% or to use a cement binder substitution with a combination of additives in proportions 10% SF + 10% FA. On the other hand, the composition of mineral additives in proportions 10% SF + 20% FA has a negative effect on the fracture mechanics parameters of concretes at an early age. Based on the analysis of the results of microstructural tests and the evaluation of the propagation of macroscopic cracks, it was established that along with the substitution of the cement binder with the combination of mineral additives, the composition of the cement matrix in these composites changes, which implies a different, i.e., quasi-plastic, behavior in the process of damage and destruction of the material.

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“…Alkali-activated fly ash (fly ash-based geopolymer) is considered as an environmentally favourable alternative to Portland cement for the lower amount of CO 2 emission, massive waste recycling and lower cost [ 12 , 13 , 14 , 15 , 16 ]. Furthermore, a geopolymer has advantages of high strength, and excellent resistance to fire, acid and sulphate attack [ 13 , 17 , 18 ], which makes it attractive in this application. A case study conducted by Sandanayake et al [ 19 ] showed that a fly ash-based geopolymer gave a reduction of 3.63–41.57% for the CO 2 emission, and 23.80–30.25% reduction for production cost.…”

Section: Introductionmentioning

confidence: 99%

Setting and Hardening Behaviour of Alkali-Activated Landfilled Fly Ash–Slag Binder at Room Temperature

et al. 2020

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A geopolymer is normally considered an environmentally friendly binder due to the utilisation of industrial wastes. This study focusses on the potential of geopolymer preparation at room temperature from landfilled fly ash (LFA) which has been discharged to the land for more than three years. To accelerate the reaction process, 20–30 wt.% LFA was replaced by ground-granulated blast-furnace slag (GGBS). The effect of water glass modulus, Na2O content, water-to-solid ratio, and GGBS content on the setting time and strength development of the binder was discussed. Results showed that to activate LFA, the optimal value of the sodium silicate modulus for alkaline solution was 1.4–1.6 with a Na2O content of 10%, and the water-to-solid ratio was 0.4. In addition, the setting time of the binder reduced with increasing content of GGBS replacement, and the compressive strength increased due to the coexistence of C-(A)-S-H and zeolite-like phases. The maximum compressive strength of the binder was 29.2 MPa after 56 days of curing. The relatively low strength was likely due to the absence of the Q4 unit with a three-dimensional structure.

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Properties of fresh and hardened fly ash/slag based geopolymer concrete: A review

Cited by 336 publications

References 111 publications

Protective Geopolymer Coatings Containing Multi-Componential Precursors: Preparation and Basic Properties Characterization

Protective Geopolymer Coatings Containing Multi-Componential Precursors: Preparation and Basic Properties Characterization

Studies of Fracture Toughness in Concretes Containing Fly Ash and Silica Fume in the First 28 Days of Curing

Setting and Hardening Behaviour of Alkali-Activated Landfilled Fly Ash–Slag Binder at Room Temperature

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