Amer, Omar

Rangaraju, Prasad

English

Clemson University: TigerPrints

Clemson UniversityTigerPrintsGraduate Research and Discovery Symposium(GRADS) Student Works4-2019Use of agglomerated geopolymer pellets as a partialreplacement for reactive aggregates to mitigateAlkali Silica Reaction (ASR)Omar AmerClemson UniversityPrasad RangarajuClemson UniversityFollow this and additional works at: https://tigerprints.clemson.edu/grads_symposiumPart of the Civil Engineering CommonsThis Poster is brought to you for free and open access by the Student Works at TigerPrints. It has been accepted for inclusion in Graduate Research andDiscovery Symposium (GRADS) by an authorized administrator of TigerPrints. For more information, please contact kokeefe@clemson.edu.Recommended CitationAmer, Omar and Rangaraju, Prasad, "Use of agglomerated geopolymer pellets as a partial replacement for reactive aggregates tomitigate Alkali Silica Reaction (ASR)" (2019). Graduate Research and Discovery Symposium (GRADS). 304.https://tigerprints.clemson.edu/grads_symposium/304An average of 375,000 tons of waste glass fibers islandfilled each year in the US [1].ASR = Alkalis in pore solution + reactive silica fromaggregate + moisture = expansive ASR gel that leadsto cracks in concrete.Previous research has shown ground glass fibers(GGF) to be an effective SCM to mitigate ASR [2,3].Nevertheless, using SCMs, in general, could delay thestrength development and setting time.Additionally, GGF has also been found to be very aneffective precursor for geopolymer concrete [4].Another research showed that the extent of ASRreaction was lower in geopolymer concrete than inPortland cement concrete [5].The investigated hypothesis here is: if a partiallygeopolymerized pellets were used in combination withreactive aggregate, there would be a competing reactionbetween ASR and geopolymerization processes, and thelatter most likely will dominate; which could lead to thereduction or the elimination of the ASR-related damages.The objective of this study is to evaluate theeffectiveness of using GGF-based geopolymer pellets(GGFGPs) as a partial replacement of highly reactiveaggregates to mitigate ASR.Ground Glass Fibers (GGF) from PPG Inc. (Shelby,NC) used as the precursor for geopolymerized pellets.Alkali activator solution: NaOH pellets were used toprepare an 8N solution.Crushed aggregate from Placitas gravel pit, NM andJobe sand were used as reactive aggregate.As for the test method, the accelerated mortar bar test(ASTM C1260) was followed to evaluate the ASRpotential of GGFGPs and the reactive aggregates,independently as well as in combination.Use of agglomerated geopolymer pellets as a partial replacement for reactive aggregates to mitigate Alkali Silica Reaction (ASR) Omar Amer and Prasad RangarajuGlenn Department of Civil Engineering, Clemson UniversityI would like to thank Dr. Prasad Rangaraju for his continuous support,valuable insights, and research guidance. I would also like to thank Thegraduate student government at Clemson University for this great opportunityto showcase this on-progress research.Omar Amer, oamer@g.Clemson.eduAbility of GGF to mitigate ASR when used as a SCM with Placitas Aggregate [1]The properties of the produced GGFGPs:Testing the reactivity of GGFGPs:The ASR performance of combinations of GGFGPs and reactive aggregate: Looking at Figure 4, it clearly shows the benefit ofusing GGF as pozzolan to partially replace cement interms of ASR mitigation. A replacement ratio of 20%or higher was sufficient to yield a 14-day expansionless than the 0.1% limit specified by ASTM C1260. Figure 5 shows how effective GGF is in producinggeopolymer that is activated only by NaOH solution. Reviewing table 1, the specific gravity and roddedUW of GGFGPs is about 30% less than the averagenatural normal-weight aggregate’s. Also, the producedGGFGPs have high absorption ratio which makes itnecessary to add the absorbed water when mortar isprepared. Figure 6 shows that although GGF is glass, which initself is very reactive, the performance of the producedpellets was acceptable in terms of ASR relatedexpansion. Investigating the pessimum ratio, results indicatedthat at 80% GGFGP content, the maximumexpansion was still less than 0.1%.Figure 8: Pessimum Ratio for GGFGP at 14 days HOWEVER, when GGFGPs tested in combinations with reactive aggregate, as figure 7 indicates, the effect on ASR expansion was a little lower than the dilution effect. The reason might have been that the pellets may have geopolymerized sufficiently that they may have not absorbed alkali from pore solution as readily.Hemmings, R. Process for Converting Waste Glass Fiber into Value-ddedProducts. DOE Report No. DE-FG36-03GO13015. Albacem, LLC, Peoria, Ill.,2005Rangaraju, P. R., et al. "Properties and Performance of Ground Glass Fiber as aPozzolan in Portland Cement Concrete." International Concrete SustainabilityConference, Washington, DC. 2016.Rashidian-Dezfouli, Hassan, Kaveh Afshinnia, and Prasada Rao Rangaraju."Efficiency of Ground Glass Fiber as a cementitious material, in mitigation ofalkali-silica reaction of glass aggregates in mortars and concrete." Journal ofBuilding Engineering 15 (2018): 171-180.Rashidian-Dezfouli, H., and P. R. Rangaraju. "Comparison of strength anddurability characteristics of a geopolymer produced from fly ash, ground glassfiber and glass powder." Materiales de Construcción 67.328 (2017): 136.Kupwade-Patil, Kunal, and Erez Allouche. "Effect of alkali silica reaction (ASR) ingeopolymer concrete." World of Coal Ash (WOCA) conference. 2011.The Reactivity of GGFGPs will be further  investigated by running ASTM C227.Microstructural analysis.Optimization of the GGFGPs quality.Further investigation of ASR performance for concrete by running ASTM C1293 or AASHTO TP110Preparation of GGFGPs:Disk Pelletizer was used. A few trials were run todetermine the appropriate settings to create the pellets.Disc rotation speed of 40 RPM and a 45◦ inclinationangle were used. After GGFGPs were made, they werecured at 60◦C for 48 hours.Test Reactivity of GGFGPsThe GGFGPs were crushed to meet the gradationrequirements of ASTM C1260, then the mortar bars wereprepared and tested for ASR.Test Potential for ASR for combinations ofreactive aggregate and GGFGPsGGFGP replacement levels of 25%, 50%, and 75% weretested with both NM crushed aggregate and Jobe sand.The amount of water absorbed by the GGFGPs wasadded for each mixture.• Prepare the GGFGPs PHASE 1• Test the reactivity of GGFGPs.PHASE 2• Test the ASR mitigation performance for the GGFGPs.PHASE 3Figure1: The ground glass fibers GGF [2] Figure 2: The GGFGPs0.810.430.04 0.0200.20.40.60.810 10 20 3014 Day Expansion, %GGF content (replacement ratio), %Figure 3: the Disc PelletizerSpecific Gravity 1.75Absorption Ratio,% 15%Rodded Unit weight, pcf 69.3Table 1: Physical Properties of GGFGPs0.080250.09100.10 7 14 21 28EXPANSION, %SOLUTION EXPOSURE TIME, DAYSFigure 6: Expansion due to ASR for GGFGPs as fine aggregateFigure 4: 14-day expansion when GGF introduced as pozzolanFigure 7: ASR test results for Combinations of reactive aggregate and GGFGPs00.020.040.060.080.10 50 100 150EXPANSION, %GGF-BASED GEOPOLYMER PELLETS CONTENT8,6749,5880200040006000800010000Compressive Strength, psi7-Day strength                          28-Day strengthFigure 5: Compressive strength for GGF-based geopolymer mortar• So far, the use of GGFGPs has not been provedto be effective to mitigate ASR. Unlike when theGGF was introduced as a SCM where ASR-related damages were extensively reduced at 20%replacement or higher.00.20.40.60.8100.20.40.60.810 50 100Expansion, %GGFGPs contentJobe SandPlacitasDilutionlineJobeDilutionLinePlacitasaggregateObjective of the studyResearch MethodologyIntroductionMaterials and MethodsExperimental ProgramResults and DiscussionTo-Date ConclusionFuture ScopeLiterature cited AcknowledgmentsResearch Hypotheses

Use of agglomerated geopolymer pellets as a partial replacement for reactive aggregates to mitigate Alkali Silica Reaction (ASR)

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Use of agglomerated geopolymer pellets as a partial replacement for reactive aggregates to mitigate Alkali Silica Reaction (ASR)

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