The bond between geopolymer repair mortars and OPC concrete substrate: Strength and microscopic interactions

Wang, Yanshuai; Peng, Kai Di; Alrefaei, Yazan; Dai, Jian‐Guo

doi:10.1016/j.cemconcomp.2021.103991

Cited by 85 publications

(20 citation statements)

References 51 publications

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“…On the other hand, the average τ b of N50-0.1-L and N30-0.1-L using middle and low-strength concrete was greater than that of the counterpart GC specimen G50-0.1-L and G30-0.1-L. Such result is inconsistent with the existing study results 7,8 that the bar bond strength at GC is greater than that of PCC. This is because, unlike the pull-out test used in the existing studies, the bond performance of beam longitudinal bars at the beam-column joint under cyclic loading is affected by various factors.…”

Section: Strains Of Beam Longitudinal Barscontrasting

confidence: 74%

“…Compared with cementitious concrete, freshly mixed geopolymer concrete (GC) has less workability. 1,2 Hardened GC provides higher early strength, 3,4 greater durability 5,6 and bond performance, 7,8 but has less elastic modulus 9,10 and greater brittleness than PCC. 11,12 Producing geopolymer concrete (GC) reduces CO 2 emissions by 75-84%, compared to producing Portland cement concrete (PCC).…”

Section: Introductionmentioning

confidence: 99%

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Seismic performance of interior beam‐column joints using reinforced slag‐based geopolymer concrete

Mao

Hwang

et al. 2022

Earthq Engng Struct Dyn

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Although geopolymer concrete (GC) is recognized as a green and low‐carbon material, GC structural members, particularly beam‐column joints, have been rarely studied. In the present study, eight reinforced GC joints and three reinforced concrete (RC) interior beam‐column joints were tested under cyclic loading. The test parameters were the concrete type, joint shear demand‐to‐capacity ratio, and axial‐compression ratio. The structural performance, including the failure mode, crack development, cyclic behavior of reinforced GC beam‐column joints, was evaluated. The test results showed that the cyclic behavior and crack development of the reinforced GC beam‐column joints differed from those of RC beam‐column joints. The increase of axial compression ratio improved the seismic performance of reinforced GC beam‐column joints with the joint shear demand‐to‐capacity ratio of 0.96–1.01. When the joint shear demand‐to‐capacity ratio was 1.54–1.61, the increase of axial compression ratio (0.1–0.3) improved the seismic performance, while the axial compression ratio of 0.5 was unfavorable because of significant joint shear damage. The applicability of the control conditions in the current design codes to the reinforced GC joints was evaluated. The control conditions of ACI 318–19 were applicable to the seismic design of reinforced GC beam‐column joints. On the other hand, the control conditions of GB50010‐2010 were not applicable because of the overestimated upper limit value of the joint shear demand‐to‐capacity ratio and axial compression ratio.

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Section: Strains Of Beam Longitudinal Barscontrasting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Seismic performance of interior beam‐column joints using reinforced slag‐based geopolymer concrete

Mao

Hwang

et al. 2022

Earthq Engng Struct Dyn

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“…However, because of the significant differences between the chemical and mineralogical composition of low-Ca AAMs and conventional concretes, and because of the tendency of substantial shrinkage and associated cracking/spalling of high-Ca AAMs (alkali-activated slags) [46,47], a strong and durable bond cannot be assumed a priori. Knowledge in this regard is only beginning to accumulate [48][49][50][51]; thus, additional studies, particularly considering the long-term behaviour of the bond, are required.…”

Section: Additional Propertiesmentioning

confidence: 99%

Acid resistance of alkali-activated materials: recent advances and research needs

Gluth¹,

Grengg²,

Ukrainczyk³

et al. 2022

RILEM Tech Lett

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Cementitious materials are frequently applied in environments in which they are exposed to acid attack, e.g., in sewer systems, biogas plants, and agricultural/food-related industries. Alkali-activated materials (AAMs) have repeatedly been shown to exhibit a remarkably high resistance against attack by organic and inorganic acids and, thus, are promising candidates for the construction and the repair of acid-exposed structures. However, the reaction mechanisms and processes affecting the acid resistance of AAMs have just recently begun to be understood in more detail. The present contribution synthesises these advances and outlines potentially fruitful avenues of research. The interaction between AAMs and acids proceeds in a multistep process wherein different aspects of deterioration extend to different depths, complicating the overall determination of acid resistance. Partly due to this indistinct definition of the ‘depth of corrosion’, the effects of the composition of AAMs on their acid resistance cannot be unambiguously identified to date. Important parallels exist between the deterioration of low-Ca AAMs and the weathering/corrosion of minerals and glasses (dissolution-reprecipitation mechanism). Additional research requirements relate to the deterioration mechanism of high-Ca AAMs; how the character of the corroded layer influences the rate of deterioration; the effects of shrinkage and the bond between AAMs and substrates.

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“…Moradi et al [23] defined metakaolin as a cementitious material derived by heating kaolin at 500-600 • C. On the other hand, fly ash is a waste product of the coal-fired power generation industry that can harm the environment when not disposed of correctly [24]. Wang et al [25] mentioned that fly ash is used in the construction industry as an admixture that strengthens and enhances the durability of concretes.…”

Section: Precursorsmentioning

confidence: 99%

Geopolymers as Sustainable Material for Strengthening and Restoring Unreinforced Masonry Structures: A Review

et al. 2021

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Unreinforced masonry (URM) structures are vulnerable to earthquakes; thus, materials and techniques for their strengthening and restoration should be developed. However, the materials used in some of the existing retrofitting technologies for URM and the waste produced at its end-of-life are unsustainable. The production of ordinary Portland cement (OPC) worldwide has enormously contributed to the global carbon footprint, resulting in persistent environmental problems. Replacing OPC with geopolymers, which are more sustainable and environmentally friendly, presents a potential solution to these problems. Geopolymers can replace the OPC component in engineering cementitious composites (ECC), recommended to strengthen and restore URM structures. In the present paper, the state-of-the-art knowledge development on applying geopolymers in URM structures is discussed. The discussion is focused on geopolymers and their components, material characterization, geopolymers as a strengthening and restoration material, and fiber-reinforced geopolymers and their application to URM structures. Based on this review, it was found that the mechanical properties of geopolymers are on par with that of OPC; however, there are few studies on the mentioned applications of geopolymers. The characterization of geopolymers’ mechanical and physical properties as a restoration material for URM structures is still limited. Therefore, other properties such as chemical interaction with the substrate, workability, thixotropic behavior, and aesthetic features of geopolymers need to be investigated for its wide application. The application method of geopolymer-based ECC as a strengthening material for a URM structure is by grouting injection. It is also worth recommending that other application techniques such as deep repointing, jacketing, and cement-plastering be explored.

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The bond between geopolymer repair mortars and OPC concrete substrate: Strength and microscopic interactions

Cited by 85 publications

References 51 publications

Seismic performance of interior beam‐column joints using reinforced slag‐based geopolymer concrete

Seismic performance of interior beam‐column joints using reinforced slag‐based geopolymer concrete

Acid resistance of alkali-activated materials: recent advances and research needs

Geopolymers as Sustainable Material for Strengthening and Restoring Unreinforced Masonry Structures: A Review

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