Sulfate Resistance of Recycled Aggregate Concrete with GGBS and Fly Ash-Based Geopolymer

Xie, Jianhe; Zhao, Jianbai; Wang, Junjie; Wang, Chonghao; Huang, Peiyan; Fang, Chi

doi:10.3390/ma12081247

Cited by 82 publications

(36 citation statements)

References 62 publications

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“…For example, Somna et al (39) found better results for 100% RCA concrete than for control concrete when 50% of bagasse ash was used as partial replacement of cement. Similar results regarding the benefit of using supplementary cementitious materials (SCM) in RAC are reported in several other studies (40)(41)(42)(43)(44)(45). All these results are explained by the reduction in the porosity that SCMs provide to the RAC matrix.…”

Section: Introductionsupporting

confidence: 87%

Long-term sulfate attack on recycled aggregate concrete immersed in sodium sulfate solution for 10 years

et al. 2020

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The effect of recycled concrete aggregate (RCA) on concrete performance against external sulfate attack (ESA) is not yet fully known. In this paper, recycled aggregate concretes (RAC) with 0, 50, 75 and 100% of RCA contents were evaluated after 10 years of exposure immersed in 50g/l sodium sulfate solution. Sulfate ingress profiles were obtained by wet chemical analyses and FRX. Also, the mineralogy of the ingress profile was evaluated by thermogravimetric analyses. Finally, microcracking development in samples was evaluated by optical fluorescent microscopy image analysis. Although RAC showed a slight increase in sulfate ingress, due to its higher porosity (about 30% higher SO3 content near the surface for 50% or higher replacement ratio than control concrete), a dense new matrix still allows a good performance of RAC to external sulfate attack with even 100% RCA content.

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Section: Introductionsupporting

confidence: 87%

Long-term sulfate attack on recycled aggregate concrete immersed in sodium sulfate solution for 10 years

et al. 2020

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“…The increase in the carbonation depth observed in samples containing RCA could be attributed to the higher permeability of RCA due to the presence of old mortar adhering to the NA and the old interfacial transition zone (ITZ) [ 105 ]. The geopolymer RCA, with a higher content of granulated blast furnace slag, had a lower mass loss and a higher residual compressive strength after the sulfate exposure [ 106 ]. The results indicate a direct influence between the percentage of aggregate used in the GC mixes and the level of corrosion that all the specimens present in both the control medium and the aggressive medium.…”

Section: Resultsmentioning

confidence: 99%

Corrosion Behavior of Steel-Reinforced Green Concrete Containing Recycled Coarse Aggregate Additions in Sulfate Media

et al. 2020

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Novel green concrete (GC) admixtures containing 50% and 100% recycled coarse aggregate (RCA) were manufactured according to the ACI 211.1 standard. The GC samples were reinforced with AISI 1080 carbon steel and AISI 304 stainless steel. Concrete samples were exposed to 3.5 wt.% Na2SO4 and control (DI-water) solutions. Electrochemical testing was assessed by corrosion potential (Ecorr) according to the ASTM C-876-15 standard and a linear polarization resistance (LPR) technique following ASTM G59-14. The compressive strength of the fully substituted GC decreased 51.5% compared to the control sample. Improved corrosion behavior was found for the specimens reinforced with AISI 304 SS; the corrosion current density (icorr) values of the fully substituted GC were found to be 0.01894 µA/cm2 after Day 364, a value associated with negligible corrosion. The 50% RCA specimen shows good corrosion behavior as well as a reduction in environmental impact. Although having lower mechanical properties, a less dense concrete matrix and high permeability, RCA green concrete presents an improved corrosion behavior thus being a promising approach to the higher pollutant conventional aggregates.

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“…Geopolymers are a representative example of an admixture that may be used as an AAM. Xie et al [11] experimentally verified that GGBFS-and FA-based geopolymers can provide the excellent sulfuric acid resistance of recycled concrete. AAMs, however, are not yet used in the field due to their fast setting time, large shrinkage, and high unit price.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Optimum CaO Content Range for High Volume FA Based Concrete Considering Durability Properties

Lee

Choi

et al. 2020

Applied Sciences

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There have been many studies on the effect of durability and compressive strength on the increase of the mixing rate of admixtures. However, there is no research that can provide a guide on the optimal mixture proportions for maintaining compressive strength and secure durability properties when using local materials. Therefore, the purpose of this article is to assess the durability and engineering performances of concrete based on local fly ash (FA), as well as to derive the optimum CaO content scope for ensuring durability. The results of this study were compared with the results of the previous study of high-volume ground-granulated blast-furnace slag (GGBFS) concrete. To achieve this, tests were carried out by increasing the admixture mixing rate in 10% increments from 0% to 70%. The unit water was set at 175 kg/m3 and the amount of binder was set at 330 kg/m3. It was found that the overall compressive strength of the hardened concrete decreased when the admixture mixing rate increased. In addition, the compressive strength of specimens tended to improve as all the CaO contents of the admixture types increased. When the durability properties were examined, it was found that the relative dynamic elasticity modulus and carbonation depth decreased, and the chloride penetration depth increased as the CaO content increased for both GGBFS and FA. The weight loss rate, however, remained similar. Based on the results of this study, the optimal CaO content that achieved satisfactory engineering and durability properties was found to be between 39% and 48% for FA. The results of this study will be able to offer guidelines for the mixture rates of FA when mixing durable concrete for use in the field. Additionally, these results are expected to be utilized as a basis for determining instructions relating to chemical composition in order to develop binders with improved durability.

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Sulfate Resistance of Recycled Aggregate Concrete with GGBS and Fly Ash-Based Geopolymer

Cited by 82 publications

References 62 publications

Long-term sulfate attack on recycled aggregate concrete immersed in sodium sulfate solution for 10 years

Long-term sulfate attack on recycled aggregate concrete immersed in sodium sulfate solution for 10 years

Corrosion Behavior of Steel-Reinforced Green Concrete Containing Recycled Coarse Aggregate Additions in Sulfate Media

Assessment of Optimum CaO Content Range for High Volume FA Based Concrete Considering Durability Properties

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