Bonding Properties between Fly Ash/Slag-Based Engineering Geopolymer Composites and Concrete

Wang, B. L.; Feng, Hu; Huang, Hao; Guo, Aofei; Zheng, Yiming; Wang, Yan

doi:10.3390/ma16124232

Cited by 6 publications

(3 citation statements)

References 39 publications

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“…The results indicate that replacing cement with 50% GGBS increases the degree of crystallinity from 28 to 90 days, while the degree of crystallinity decreases for the standard mortar, on the degree of reaction of the binder [79]. For the MII/360 slag mortar with a higher specific surface at the age of 28 days, it approaches that of the standard mortar.…”

Section: X-ray Diffractionmentioning

confidence: 89%

Potential Role of GGBS and ACBFS Blast Furnace Slag at 90 Days for Application in Rigid Concrete Pavements

Nicula,

Manea,

Simedru

et al. 2023

Materials

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Incorporating blast furnace slag into the composition of paving concrete can be one of the cost-effective ways to completely eliminate by-products from the pig iron production process (approximately 70% granulated slag and 30% air-cooled slag). The possibility to reintroduce blast furnace slag back into the life cycle will provide significant support to current environmental concerns and the clearance of tailings landfills. Especially in recent years, granulated and ground blast furnace slag (GGBS) as a substitute for cement and air-cooled blast furnace slag (ACBFS) aggregates as a substitute for natural aggregates in the composition of concretes have been studied by many researchers. But concrete compositions with large amounts of incorporated blast furnace slag affect the mechanical and durability properties through the interaction between the slag, cement and water depending on the curing times. This study focuses on identifying the optimal proportions of GGBS as a supplementary cementitious material (SCM) and ACBFS aggregates as a substitute to natural sand such that the performance at 90 days of curing the concrete is similar to that of the control concrete. In addition, to minimize the costs associated with grinding GGBS, the hydration activity index (HAI) of the GGBS, the surface morphology, and the mineral components were analyzed via X-ray diffraction, scanning electron microscopy (SEM), energy dispersive spectrometry (EDX), and nuclear magnetic resonance relaxometry (NMR). The flexural strength, the basic mechanical property of road concretes, increased from 28 to 90 days by 20.72% and 20.26% for the slag concrete but by 18.58% for the reference concrete. The composite with 15% GGBS and 25% ACBFS achieved results similar to the reference concrete at 90 days; therefore, they are considered optimal percentages to replace cement and natural sand in ecological pavement concretes. The HAI of the slag powder with a specific surface area equivalent to that of Portland cement fell into strength class 80 at the age of 28 days, but at the age of 90 days, the strength class was 100. The results of this research present three important benefits: the first is the protection of the environment through the recycling of two steel industry wastes that complies with European circular economy regulations, and the second is linked to the consequent savings in the disposal costs associated with wastefully occupied warehouses and the savings in slag grinding.

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Section: X-ray Diffractionmentioning

confidence: 89%

Potential Role of GGBS and ACBFS Blast Furnace Slag at 90 Days for Application in Rigid Concrete Pavements

Nicula,

Manea,

Simedru

et al. 2023

Materials

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“…Changes in interface roughness can significantly affect the interfacial bond strength, mainly due to increased interfacial shear friction and mechanical interlocking between different concrete layers [45]. Wang et al [46] found that, when using EGC to reinforce existing concrete, increasing the ductility of EGC does not result in higher interfacial bond strength, whereas improving the interfacial roughness effectively enhances the interfacial bonding performance. Under shear conditions, sufficient interface roughness can change the location of failure in a component (from the bond interface to either the reinforcement layer or the existing concrete layer) [43].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Bond Performance at the Interface between Engineered Geopolymer Composites and Existing Concrete

Li,

Tan,

Ouyang

et al. 2024

Buildings

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Engineered geopolymer composite (EGC) exhibits ultra-high toughness, excellent crack control capability, and superior durability, making it highly promising for applications in bridge connecting slabs, wet joints of prefabricated components, and concrete structure reinforcement. However, the bond performance and failure mechanisms at the interface between EGC and existing concrete remain unclear. To elucidate the bond performance of EGC to existing concrete, direct shear tests were conducted on 15 sets of EGC–existing concrete bond specimens. This study explored the effects of existing concrete strength, interface roughness, and EGC strength on the bond performance and mechanisms. Additionally, a direct shear bond mechanical model was established to predict the interface bond strength. The results indicate that, with comparable compressive strength, the preparation of EGC can reduce the total carbon emissions by up to 127% compared to ECC. The failure mode of EGC-existing concrete bond specimens was mainly adhesive failure (except for specimen C30-III-G95), which can be categorized into serrated interfacial failure and alternating crack paths. The change in interface roughness was the primary factor leading to the transition between failure paths. The changes in interface roughness and EGC strength significantly influenced the bond performance. Under their combined effect, the interface bond strength of specimen C50-III-G95 increased by 345% compared to C50-I-G45. In contrast, the improvement in existing concrete strength had a relatively smaller effect on the increase in interface bond strength. Based on the experimental results and the bonding mechanism under direct shear stress, a direct shear bond mechanical model correlating existing concrete strength, interface roughness, and EGC strength was established. The model predictions showed good consistency with the experimental results. This study provides theoretical support and experimental data for the engineering application of EGC.

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“…The sample life and processing temperature are also significant factors that can affect the mechanical properties of geopolymers. However, other factors will be practical only if the activator concentration is sufficient to advance the geopolymerization process [39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Effect of Acid and Thermo-Mechanical Attacks on Compressive Strength of Geopolymer Mortar with Different Eco-Friendly Materials

Teshnizi,

Karimiazar,

Baldovino

2023

Sustainability

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This research examined how changing the ratios of certain substances affected the strength and durability of a specific type of building material when exposed to acid and heat. This study used various combinations of zeolite, metakaolin, slag, and Portland cement as primary materials. It also used different amounts of potassium hydroxide (KOH) to make the geopolymer mortar. The concentrations of KOH used were 8 M, 12 M, 14 M, and 16 M. The cement-based material had the highest water absorption. A total of 240 tests were conducted, including 20 samples for each mix design tested at curing times of 7, 14, 21, 28, and 90 days. The results showed that the samples made with slag base material and 8 M mixing design had the highest average compressive strength at 28 and 90 days in the acidic environment test, and the zeolite and metakaolin base material samples had the highest corrosion and weight loss, possibly due to their high specific surface and aluminosilicate origin. The samples made with slag-based material had better resistance and the highest average compressive strength in the 300 °C and 500 °C thermo-mechanical tests. The lowest average compressive strength in the thermal and mechanical stress test was related to the samples made with a metakaolin base material. The tests performed on the samples made with slag base material had better compressive strength than the three other base materials in the acid and heat tests. The zeolite-based mortar lost the most weight under 30% acidic sulfuric water. The findings suggest that changes in the molar ratios of alkaline activators can significantly affect the durability properties and strength of geopolymer mortar, and the slag-based material with an 8 M mixing design had the best performance; also, SEM analysis verified this mechanism.

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Bonding Properties between Fly Ash/Slag-Based Engineering Geopolymer Composites and Concrete

Cited by 6 publications

References 39 publications

Potential Role of GGBS and ACBFS Blast Furnace Slag at 90 Days for Application in Rigid Concrete Pavements

Potential Role of GGBS and ACBFS Blast Furnace Slag at 90 Days for Application in Rigid Concrete Pavements

Experimental Investigation of the Bond Performance at the Interface between Engineered Geopolymer Composites and Existing Concrete

Effect of Acid and Thermo-Mechanical Attacks on Compressive Strength of Geopolymer Mortar with Different Eco-Friendly Materials

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