Mix design and mechanical properties of geopolymer and alkali activated concrete: Review of the state-of-the-art and the development of a new unified approach

Xie, Tianyu; Visintin, Phillip; Zhao, Xinyu; Gravina, Rebecca

doi:10.1016/j.conbuildmat.2020.119380

Cited by 104 publications

(59 citation statements)

References 129 publications

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“…In Figure 18 a, an increase of resistivity with increasing Ksil content is shown: this behavior can be explained by the fact that for geopolymer formulations, in general, exists an optimum concentration of the activator to reach the best mechanical performances, which occur when the concentration of alkali activator ions (K + in our case) equals the concentration of Al 3+ ions of the aluminum–silicate network of the forming geopolymer [ 16 ]. The presence of K + excess leaves unreacted activator that eventually carbonates and can lead to a decrease in mechanical properties due to incomplete geopolymerization.…”

Section: Resultsmentioning

confidence: 99%

“…Geopolymers [ 13 ] are inorganic binders different from regular concretes since they do not form calcium silicate hydrates for strength but are based on the polycondensation of silica and alumina with high alkali content. They have attracted the attention of researchers from different engineering fields owing to their modular environmentally friendly preparation procedure (low temperature, no harmful gas emission) [ 14 ], feasibility to incorporate high volumes of wastes or metal particles to produce value-added building materials with excellent physical and mechanical properties [ 15 , 16 , 17 ]. As an example, the incorporation of fly ash into geopolymers has been demonstrated to improve thermal stability and mechanical properties, thus providing an experimental basis for the utilization of solid waste soda residues and recycling of waste concrete [ 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

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Novel Magnetic Inorganic Composites: Synthesis and Characterization

et al. 2021

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The addition of magnetic particles to inorganic matrices can produce new composites exhibiting intriguing properties for practical applications. It has been previously reported that the addition of magnetite to concrete improves its mechanical properties and durability in terms of water and chloride ions absorption. Here we describe the preparation of novel magnetic geopolymers based on two different matrices (G1 without inert aggregates and G2 with inert quartz aggregates) containing commercial SrFe12O19 particles with two weight concentrations, 6% and 11%. The composites’ characterization, including chemical, structural, morphological, and mechanical determinations together with magnetic and electrical measurements, was carried out. The magnetic study revealed that, on average, the SrFe12O19 magnetic particles can be relatively well dispersed in the inorganic matrix. A substantial increase in the composite samples’ remanent magnetization was obtained by embedding in the geopolymer SrFe12O19 anisotropic particles at a high concentration under the action of an external magnetic field during the solidification process. The new composites exhibit good mechanical properties (as compressive strength), higher than those reported for high weight concretes bearing a similar content of magnetite. The impedance measurements indicate that the electrical resistance is mainly controlled by the matrix’s chemical composition and can be used to evaluate the geopolymerization degree.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Novel Magnetic Inorganic Composites: Synthesis and Characterization

et al. 2021

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“…AAC concrete is a concrete produced from industry byproduct materials such as fly ash and slag. It has highly desirable characteristics such as high strength, excellent fire resistance, and acid resistance [3][4][5][6]. Most importantly, AAC is much more environmentally friendly than conventional concrete because of its zero cement consumption.…”

Section: Introductionmentioning

confidence: 99%

“…The mean value of the flexural strength as per this standard is determined by multiplying the characteristic value by 1.4. The relationship between the mean compressive strength and the characteristic strength is given by Equation (6) for a concrete grade in the range of 25 to 65 MPa.f ct,f = 0.6 f c(5)…”

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confidence: 99%

Mechanical Behavior and Frost-Resistance of Alkali-Activated Cement Concrete with Blended Binder at Ambient Curing Condition

et al. 2021

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Concrete is the most commonly used construction material because of its various advantages, such as versatility, familiarity, strength, and durability, and it will continue to be in demand far into the future. However, with today’s sensitivity to environmental protection, this material faces unprecedented challenges because of its high greenhouse gas emissions, mainly during cement production. This paper investigates one of the promising cement replacement materials, alkali-activated cement (AAC) concrete. Being produced mainly from byproduct materials and having a comparable structural performance to conventional concrete, AAC concrete can transform the construction industry. Mechanical properties such as compressive and flexural strength and the relationship between them are studied. Different source materials such as fly ash (FA), ground granulated blast furnace slag (GGBS), silica fume (SF), and Metakaolin (MK) are used. The effect of the source materials and the activator solutions on the concrete performance is studied. Furthermore, the freeze-thaw resistance of the concrete is studied. The study results showed that the behavior of AAC depends highly on the source material combinations and type used. The effect of the alkaline solution is also dependent on the source material used. Mixes with higher GGBS content showed the highest strength, while mixes with MK showed the highest flexural strength. The freeze-thaw test results showed that proper design of AAC concrete with lower water content is critical to achieving a good resistance.

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“…Low-calcium fly ash geopolymer concrete (FAGC) is regarded as an alternative to Portland cement concrete (PCC) [ 1 , 2 , 3 ] because of its low energy consumption and CO 2 emissions, early compressive strength under slightly elevated temperatures [ 4 ], superior durability in sulphates or acids [ 5 , 6 ], and excellent fire-resistance behavior [ 7 ]. The necessary heat curing of FAGC is considered to limit its application in precast industries only, but the limitation can be overcome by pre-heating of fly ash and alkaline solution [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Practical Prediction Models of Tensile Strength and Reinforcement-Concrete Bond Strength of Low-Calcium Fly Ash Geopolymer Concrete

et al. 2021

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There have been a few attempts to develop prediction models of splitting tensile strength and reinforcement-concrete bond strength of FAGC (low-calcium fly ash geopolymer concrete), however, no model can be used as a design equation. Therefore, this paper aimed to provide practical prediction models. Using 115 test results for splitting tensile strength and 147 test results for bond strength from experiments and previous literature, considering the effect of size and shape on strength and structural factors on bond strength, this paper developed and verified updated prediction models and the 90% prediction intervals by regression analysis. The models can be used as design equations and applied for estimating the cracking behaviors and calculating the design anchorage length of reinforced FAGC beams. The strength models of PCC (Portland cement concrete) overestimate the splitting tensile strength and reinforcement-concrete bond strength of FAGC, so PCC’s models are not recommended as the design equations.

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Mix design and mechanical properties of geopolymer and alkali activated concrete: Review of the state-of-the-art and the development of a new unified approach

Cited by 104 publications

References 129 publications

Novel Magnetic Inorganic Composites: Synthesis and Characterization

Novel Magnetic Inorganic Composites: Synthesis and Characterization

Mechanical Behavior and Frost-Resistance of Alkali-Activated Cement Concrete with Blended Binder at Ambient Curing Condition

Practical Prediction Models of Tensile Strength and Reinforcement-Concrete Bond Strength of Low-Calcium Fly Ash Geopolymer Concrete

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