Bond strength of reinforcement in concrete

Recent.ly t.rie pr-emat-ur-e det.eriorat.ion 01 concret.est.ruct.ures subject.ed t.o cost.al, urban and indust.rialinvironment. in Egypt. has become a major problem. Theorganic co at.Ing-s al’e used t.o p r-o t.e c t, r-efru or-cf ng st.eelbars embedded in coricr-e t.e f r-orn coz-r-oesi on. An Impo r-t.arrt.corrsdde r-at.Iori in t.he use 01 coat.ed r-ef.nf’or-cf ng baI”s ist-he ellect. 01 t.Ire co.at.Ing mat.e r-Lalzs on t.he bond st.I”engt.hbet.ween r-e i nf’o r-cfrrg b ar-ss and coricr-e t.e , In t.hisinvest.i~at.ion, t.he e f’f e-c t, 01 t.hr-e-e t.ypes 01 Epoxyco.at.Ing mat-er-Labs (Epoxy 131, Sika Dur 31 and Sika Top108) and one t.ype 01 admixt.uI”e (Sika Lat.ex>, on t.he bondst.ren~th 01 coat.ed r-edrif’o r-cdrrg bars in corior-e t.e havebeen de t.e r-mrnd e-xpe-r-Imerrt.edly 101” plain b ar-zs of’ di.ame-t.e r-e13,16 and 19 mm, and delormed b.ar-s 01 di ame t.e.r-ss 13 and16 mm. The elle;t. 01 t.he t.hickness 01 co at.Irig m.at.e r-Laland t.he tncr-e.asse 01 SUI”lace r-oug hneese usin~ Epoxy 131 asa coat.Ing mat.e r-Lal , on bond st.I”engt.h 01 coat.ed b ar-specimens have been examined e-xpe r-tmerrt.akly. The bondstI”en~ths wer-e de t.e r-mi ne d using pull-out. t.est.. It. wasf’ound t.hat., cer-t.af.n t.ypes 01 co.at.rng mat.er-Labs such asEpoxy 131 and Sika DuI” 31, Impr-ove-d t.he bond st.rengt.hbetween st.eel and concret.e. Also, it. was lound t.h.at. t.hebond st.I”en~t.h 01 coat.ed b ar- specimens have higheI” valuest-han t-hat. of uncoat.ed b ar- specimens dur-Ing six morrt.hs ,