Alkali-Activated Mortars Modified by Epoxy-Carbon Fiber Composites Wastes

Andrea Saccani,Stefania Manzi,Grazia Totaro,Isabella Lancellotti

doi:10.3390/app11136110

Andrea Saccani, Stefania Manzi + Show 2 more

Open Access

https://doi.org/10.3390/app11136110

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Abstract

Short chopped fibers coated by epoxy resin of different length (5 to 10 mm length) were added at low volume content (about 4.6% on the composite) to alkali-activated fly ash or metakaolin mortars. These uncured scraps derive from the production of carbon fiber-reinforced polymer composites and they are not presently recycled, despite their outstanding mechanical properties. The workability, microstructure, porosity, and physical and mechanical properties (mainly flexural strength) of the derived materials were investigated. Superior flexural strength and increased toughness were obtained. An acid treatment of the scraps further improved the mechanical properties of the mortars by changing the chemical structure of the surface, thus increasing the interaction with the inorganic phase. These results foster the use of these wastes to improve the performance of low carbon footprint building materials such as alkali-activated composites in the building industry.

Highlights

Epoxy resins reinforced by carbon fibers have outstanding mechanical properties and, because of their low density, high values of specific strength and modulus
The effect of untreated scraps of different length on the properties of mortars formulated with metakaolin or fly ashes activated by alkaline solutions was investigated
The effect is larger in fly ash ma aatmdedrdudiimaitFtiFlioisoigngfntuouhtrrteraeeenfnn4dl4dysissnshtahtoomosowrhwree)esdts,dautdtuhkchuceeaeeeotwwhtlhtiaeanoetateeammtrrhmaoaeaboutbseudnsornotiriftraopfpofletstifraioeoba(nannbsbostffooroocbrrurhbeatdaeal1dllrwla0owoc%affttateehttmrrhee.iresTa.itnxihTinvciehvmseeeesfoustefiteffmgifcgeattahctfiettoseedirdlspasmlrsaragaemreemcgtrpuaepilrkrnelseiasnflos.o.yrflTslTiayhn.hseNaheaswnmowhdaaamrsts1eteatem9e--%armkaabxli rtdieairlfisfaetlhrseatnnhcainensminwemteareketaaodkleaintoelmicntaetmderaiftaoelrsri(atahlbseo(audbtiof1fu0e%tr1em0n%taxwmimaasuxtmiemlfueomnr gmftoehrt,amokareotfaloiknraaothnliden1tar9ne%datm1e9da%xaimmnduaxmui-ntreated fmworuaflsmyteafsos.hr )f,ldyuaestho),thdeudeiftfoertehnet dchifafrearcetnetricshtiacrsaocftethriestpicrsecoufrstohres.pNreocurermsoarrsk. aNbloe rdeimffearreknacbelse wdeifrfeerdeentceecstewdefroer dtheetedcitfefderfeonrttwheasdteiffleernegntth,woarsftoerlethnegtthre,aotredfoarntdheutnrteraetaetdedanwdasutnestr.eated wastes

Summary

Introduction

Epoxy resins reinforced by carbon fibers have outstanding mechanical properties and, because of their low density, high values of specific strength and modulus. As a result, they are applied in many sectors, such as the automotive, aeronautical, and nautical industries. The added amount of waste (about 4.6 vol% of the mortars) was derived from previous studies [13], which proved how this amount provided the best conditions to obtain good mechanical properties in similar materials. Sci. 2021, 11, 6110 vol% of the mortars) was derived from previous studies [13], which proved how this amount provided the best conditions to obtain good mechanical properties in similar matgtwmtheoareaitiilesamdclnhaspc.oehprmMtoeotmvisoocseriaidecbtlaoihlstleverspeeomfiarrlb,evtem-aeeatrrnemtsehns–aiemtlttdmoewapceitamrohnsixetxpnmyorionforitcetvtehasterolienatpshcdsrcteieuirso-arsftnpirorboseslev.uawreItnsnma–dtshmteihnenpaigtesterrotpcifhfaxooestrxihemnfiy,etbetershedercreasrsticaoa,ntpibiimossnuunvwtorseor.fasonIsttunhilgpyneatedthctroeiihfnsomeagrcmmpoatisodhecesieda,fslyitftbthiotrbleheeeiaenramtsviom,meeubasettnuoneis-ftrt osnulryfatcoemofotdhiefyepthoexyoulateyresr.urface of the epoxy layer.

Mixing Procedures and Compositions

Pull-Out Test

Results

Conclusions