Petrographic method to semi-quantify the content of particles with reactive components and residual mortar in ASR-affected fine recycled concrete aggregates

Locati, Francisco; Zega, Claudio Javier; Santos, Gabriela Coelho Dos; Marfil, Silvina Andrea; Falcone, Darío Daniel

doi:10.1016/j.cemconcomp.2021.104003

Cited by 9 publications

(6 citation statements)

References 45 publications

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“…Shehata et al [2] and Johnson and Shehata [27] reported limited data on the use of the test with RCA with sizes ≥ 5 mm and found a good correlation with concrete prisms for samples with and without SCM. Besides mortar and concrete tests, a petrographic procedure was used to identify the reactivity of fine RCA, and the results were confirmed using the AMBT [9].…”

Section: Introductionmentioning

confidence: 94%

“…The original aggregate used in the demolished structure has a major impact on the RCA usability, and different precautions may need to be taken. For instance, an RCA produced from a structure that has suffered alkali-silica reaction (ASR) may continue to cause expansion if used in a new structure without preventive measures [1][2][3][4][5][6][7][8][9]. In reality, more than one deterioration mechanism is likely co-occurring.…”

Section: Introductionmentioning

confidence: 99%

“…RCA produced from concrete suffering ASR was found to cause significant expansion when used as aggregate in lab-prepared concrete prisms [1][2][3][4][5][6][7][8][9]. The expansion of concrete prisms with a natural reactive limestone (Spratt) from Ottawa, Ontario, was slightly lower than new concrete prisms made with RCA containing the same reactive aggregate [2].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A study into the alkali-silica reactivity of recycled concrete aggregates and the role of the extent of damage in the source structures: Evaluation, accelerated testing, and preventive measures

Piersanti

Shehata

2022

Cement and Concrete Composites

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A study into the alkali-silica reactivity of recycled concrete aggregates and the role of the extent of damage in the source structures: Evaluation, accelerated testing, and preventive measures

Piersanti

Shehata

2022

Cement and Concrete Composites

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“…Finally, potential ASR could be assessed using petrographic analysis using SEMs. ASR detection by petrography provides accurate detection of ASR [32,33], however, it is laborious, expensive, and destructive. Also, petrography testing is conducted in limited labs across the United States.…”

Section: Literature Reviewmentioning

confidence: 99%

Improving Concrete Infrastructure Projects Conditions by Mitigating Alkali-Silica Reactivity of Fine Aggregates

Akhnoukh¹

2023

Preprint

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Alkali-silica reactivity (ASR) is one of multiple reactions responsible for premature loss in concrete infrastructure service life. ASR is a deleterious reaction initiated when highly reactive silicious content of aggregates reacts with alkali hydroxides content within portland cement in the presence of moisture. ASR results in the formation of expansive, white-colored gel-like material which results in internal stresses within hardened concrete. ASR induced stresses result in concrete cracking, spalling, and increased reinforcement steel corrosion rates. The main objective of this research is to improve the conditions of concrete infrastructure projects conditions by mitigating ASR damaging effect. The expansion of accelerated mortar bars poured using fine aggregates collected from different sources is measured versus time to evaluate aggregate’s reactivity. Different percentages of supplementary cementitious materials (SCMs) including class c fly ash, micro-silica, were used in remixing mortar bars to evaluate the efficiency of different types of SCMs in mitigating mortar bar expansion. Research findings showed that SCMs can mitigate ASR, thus, decrease the mortar bar expansion. The efficiency of SCMs in ASR mitigation is highly dependent on the incorporated SCM percentage and particle fineness. Silica fume, having the least particle size, displayed higher rates of ASR mitigation followed by fly ash, respectively. The outcomes of this research will assist design engineers in avoiding future losses due to ASR cracking in concrete infrastructure projects, and reduce the excessive need to maintenance, repair, and replacement activities.

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“…FRCA is generally considered a very low-quality material due to its high amount of RM, resulting in low specific gravity, high porosity and absorption, the latter of which corresponds to the increased water demand of the FRCA concrete. Some studies were performed to quantify the RM of FRCA [22][23][24]; however, the quantification of the RCP is more relevant as FRCA may be composed of only RM, which makes the results obtained on those studies somewhat inconsistent [25,26]. De Andrade et al [18] used a discrete PPM approach, the so-called Compressible Packing Model (CPM) developed by De Larrard [27], to proportion recycled concrete mixtures made of 100% FRCA and found that better control over the properties of the material might be achieved despite the FRCA features; however, the RCP in the FRCA was quantified in this study only for comparative purposes.…”

Section: Background 21 Multi-phase Nature Of Recycled Concrete Aggreg...mentioning

confidence: 99%

Freezing and Thawing Resistance of Fine Recycled Concrete Aggregate (FRCA) Mixtures Designed with Distinct Techniques

et al. 2022

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The pressure to use sustainable materials and adopt practices reducing the carbon footprint of the construction industry has risen. Such materials include recycled concrete aggregates (RCA) made from waste concrete. However, concrete made with RCA often presents poor fresh and hardened properties along with a decrease in its durability performance, especially when using its fine fraction (i.e., FRCA). Most studies involving FRCA use direct replacement methods (DRM) to proportion concrete although other techniques are available such as the Equivalent Volume (EV) and Particle Packing Models (PPMs); yet their impact on the durability performance, especially its performance against freezing and thawing (F/T), remains unknown. This work, therefore, appraises the F/T resistance of FRCA mixtures proportioned through various mix proportioning techniques (i.e., DRM, EV and PPMs), produced with distinct crushing processes (i.e., crusher’s fines vs. finely ground). The results show that the mix design technique has a significant influence on the FRCA mixture’s F/T resistance where PPM-proportioned mixtures demonstrate the best overall performance, exceeding the specified requirements while DRM-proportioned mixtures failed F/T resistance requirements. Moreover, the crushing process plays an important role in the recycled mixtures’ cracking behavior under F/T cycles, where less processing leads to fewer cracks while remaining the most sustainable option overall.

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Petrographic method to semi-quantify the content of particles with reactive components and residual mortar in ASR-affected fine recycled concrete aggregates

Cited by 9 publications

References 45 publications

A study into the alkali-silica reactivity of recycled concrete aggregates and the role of the extent of damage in the source structures: Evaluation, accelerated testing, and preventive measures

A study into the alkali-silica reactivity of recycled concrete aggregates and the role of the extent of damage in the source structures: Evaluation, accelerated testing, and preventive measures

Improving Concrete Infrastructure Projects Conditions by Mitigating Alkali-Silica Reactivity of Fine Aggregates

Freezing and Thawing Resistance of Fine Recycled Concrete Aggregate (FRCA) Mixtures Designed with Distinct Techniques

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