Document J3yz2DB9oYZkErG82rmezZpmK

fUpnntM from AawcrLrtJau. EaNNO **r .un 1941 <TM*L 22. e* > )vml of 15* AsmocM s(y ol AyeaeVnarwl A. f--p*. & '% tv ':'^1 iit I i? *2 r rr 4 M -% I P- M r 51 if -p * V > i:' 'M Acid-Resistant Concrete Coatings:1 *" t - -. ., , By J^R* Spraul ' "ORK reported in this paper was undertaken to results : - . find suiroble coatings for use on concrete stave From the 91 dittorent coatings tested, the table includes silos to resist the disintegrating action of acids those found to resist-the acid flow test for more than 10 t; ncrured in ensilage Almost all the materials'used in this daj^s, and a few coatings now in genera! use, for compariv- iv were furnished by nationally known manufavrurers, ?bn. I believe that, unless the coating allows the: adhesion , : for the most part, are regularly offered for sale. This of Jjrof the id flo;. test w.U approx.- r r attempts to give a comparative picture of the value ta-h of these materials under the action of weak acid,\ -lt^avon. and water :icn. mate one yeac of actual use in a silo. Whether or not ensil age will adhere can be determined only by actual use. Some of the coatings tested were placed on silos last summer. These silos were inspected recently after one year ; ' experimental .... of use and notes on the result* of this inspection arc in : F.ach coating was subjected to two different tests. First, cluded in the following table: ;; b , -r ,i,i derated acid flow test' subjected the coating to acid a..:-.on and abrasion. The test of Miller, Rogers, and Man- son was altered by using a stronger (0.2 N) acetic acid, and the maximum period .of the test was reduced to ten days. ' ; .. ' ' ' " The accelerated acid flow test gives a comparative pic rt of the acid-resisting qualities of each coating. The vviduvtion of sand.-gravel, and cement loosened from the . 1 bar by brushing was taken as evidence of disinteu a'-.-'n. Although the loosened material obtained by the crushing wus dried and weighed, the table gives only the Coat*' la It msm- . bar IVscrips tlun amt ` coat of coating TAIHE OF RESULTS Deirrlptlon of coaltri* jrear* - Water - abstorptioo. Add How WelR^t test. Time R.vlucdi** todays of 2-incaate<t first eyi* cube in denceof v tap water diyhie- .. lor 21 hr. ^ration ... percent Uncoated concrete # . 1 ' " 6.2 WAXES 4All the waxes were applet! by me!?inje the wax, brushing It on the orwtcrcte. and drivtrx H In with a burner, leaving ni> a thin dim on the surface! . camber of days the coating withstood the test before cro- vo" appeared. b- V bb : b : - ; b, i bis test also brings out several other important "prop- c* ' of a coating. It must have good coverage or the, i -.rung will wear out thin parts of the coating and permit .'.egration to start. The coating must also form a good : ; d with the concrete to prevent peeling or pitting, both : : which permit disintegration to begin. 1b ........ The second test involved drying a 2-in cube of concrete,' - .tircly coated, in an electric oven at 75 to S3 C (degrees Parafnn i melting This -resting f*eeis point 49 C*. Cost. %rd cbeca* s*i;htly 2-3 cents t<r lb on a This v<uld t> If a silo sr-re u-me *>eer with H Ttfc/U- t-rch rVe?y . *r- ' Paraffin plusam*TO' cryAialllr.e pet*-iej:n hydrocarbon wax <mcUing' roir.t of iax. . . uMi*. VlEqusil parts. Cost of cents per 15 - \:V-.7 -b. ' T -* addiimn of the lather, .melts ng- point. - lees t.rtttle wax to the panrtin Improves the coat- tr.g. Stitt good after one year . .7 .7. ' 1 ntiera-Jc) for a period of 2a hr This temperature was ! because' ensilage .often-approaches it. The cubes were her: weighed, placed in beakers, and allowed to remain i.d.r tap w ater at room temperature for another 24 hr. .The cubes were removed, weighed again, and the percentage of absorption was calculated from the two weights. This ParafJin plus butyl methacrylate poly mer fused to gether. Cost of fMl y- tn*r. 75 cents per ih Greater than lO PR^fiin plus stearin S<'te peehng of the Creator pitvfc Cost of n.-ating near top of than 10 pitch. # cenl9 per lt silo . 51 .2l water absorption test, while contributing less to the estimatiwn of the .value of a coating than the acid flow test, is a giod measure of porosity. It was hoped that this test would g;ve j method o! predicting whether a coating would permit ctiMlage to stick to the silo wall, but in field tests, which dtscrihcd iar-.:. r.i general rule has been determined. , / All the concrete bars and cubes used in this investigawere made by the "dry tamped", method. The propor- ParafT.n plus stearin pltrh 43: U Greater ` 2.T than 19. ASPHALT COAXINGS 'Turn coats applied In between coats; e Grade A liquid as I n^itag# sticks and phalt paint. Co*?, takes ot? .some of id.cents per gat me coating all cases, Greater than 10 with 24 hr. 2.J ., 7 Heavy-duty W.i k* Excellent asphalt co.Vi^g , Cost. $2.IU per gul . ; Greater than 10 S.T :'n of. the ingredients by weight when dry Were; gravel. ' * i. coarse sand, 2.42: fine sand, 1.00; cement, 1.52. i. gugh water was then added to give a water-cement ratio > VI gal per sack of cement. These proportions make 'even staves, 12y 2 m w ide and weighing about 79 lb each; per sack of cement. The concrete was cured in a steam UUnBKH E \SF. PAINTS ft ;. . An ' paint with A fuht*cf derlviivea n ust. and cvmafning ?aphltc. Two *.nats were spjdlfd -vi*ft 4 fir between cf*ta Cost, >3.8ft per kaI Kxcellent. .' -. ' '. . ` .. ;. ; .. Greater . than 10 ft 3 - --- - chamber at about 75 C for 24 hr and then given a 7-days -curing in air at room temperature. . 9 Latex . water etr.ul- Ion. ApoUel tn same manner as no. a . .. ' ' ' Greafer thu.ito 3.7 A'-MJrd tt-lipTiH-w for pnbltra'.lort in Acsurcvn ft%L EsotNcsaiNG. t* i-.a'erial .uhnuh^ tVihe <;7 the graduate sch.>Oi of Ua.*?r*liy in ptrfl'i! fvdf.ilmerit of in* requirements for the r*h. D d'- ..r--e Author: fies*-r:h felio-v in University t Indiana D. G\ - Ri-tf-T*. .C V.. ar.d :.?*n.on. P. V/. Laboratory tf'ti ! c.r<T*te and r^.o"tarj expos'd to weait acid*. Ag?i Kngr. 23.1L <No* >mber 19391.. ' . . ' ... - - .. - . ., ' J` ' 1<> A rutf^-er-base paint Two i-oV.s were ap- . pMrd with 24 hr he- . ten C5>at. Vlrrt . coat thinned with . 13 per cent nyl.-l , CmU U-39 per gal . DSW 325653 Grester , than 10 39 v : v. -- , * *t 1 1 * *- * *%* *' - (V ^ ' STLCOPCB4075695 12 :i .v p ii i -.{* J- 7 r"* ^.'r* _ .% ''jv-"- ,, ;* -, '5 N-^ C?t y ,, r K **`-^'#v> S' -* -d?-' v:-..'. -c-is- * r-v Si.1 -Vvfc' c-o- 'Ay; W -a.X .g;.'- ^-^A-:Vrr ^.iVTAAvV- : - S*-J-XT "x '.Vv . :: ||> -.i.v* HC3IN VARN13UES 11 . :. . 80f of cumaroa* resin, 11 cu cm ot fish vtt. and 40 K of xylol. Stirred until nom^seneaua. One coat Previous experience ha* shown that this coating reps's dUJfttcsrati^n for 2*3 yr 12 Same a* No. H, ex* -cp: that l g of 125 ti dccr..i>.!s* . cnuljrmdia4-- a\*tl. (a the xylol bcfo.e tr.:x!n* with Uttf rrjj'i and fist 0<). One .*at OTfstff > then 10 368612 13 A pher.d modified Ensilage stick* c*.v-(!i-lr*; >;*< a.kyd Joints of slaves api.lt* d a* a ,Vi per ci^jVa-^-ttrvri la Tin-'.' * r.il *- ntTpiK* Nfc. V -v. vl.t iu 0j*j:U piT-V' . . ' 0*v5V C: *-*.- Cvs*. of - aik i s-duUoa. 13U .! i-r'tt -:'>' Greater thanXO x> - -4.fi . ^ 4.7 JitSCELLANEOUa sz A coat t&r derlvi* live coatlnR. On tcoldi coat applied. Coat, SO. 75 per sal ` 23 24 Stearin pitch. This coating was applied In the same man ner as the waxes Equal parts of stearin pitch art* stearic acid fused together ar.d applied by the usual wax meibod AS.v.a.vvbV.H;--'- - A" 5. v Greater than 10 : XT Greater than 10 7-7 Greater than 10 3.3 AV RESULTS OF OTHER TESTS 1 A series of coatings made up of one-half p>md ot a resin and two pounds of 125 centipoisc chlotinatol rub ber dissolved in one gallon of xylolwere placed on m|(.. O:*o -X-; ,*! a o/ruoi of a p*!y- se> frn- *'*14 . '-'a* a primer. tCost.- 4i> C'-nta per *<*1* .fallowed in-4 hr hy a r**t o' a regiUar pul>.- > r*-nt rrt;n , . - Greater than 10 4.3 last summer out not tested in the laboratory. The rt.vi used were cumarone, a liquid phenolformatdehvJc. an . vinsol. After one year's ser\-ice these coatings appear to l> in excellent condition. 2 Other waxes such as cetyl acetamide, camauba, ,crc . As*. ieTt Case pnial Good chlori nated rubhrr. T`* - /. cI'm* a;;>lied * fir^r coat ihi:o*1 - c***a .-bpwi.o . Ihliiiirr; Cost .S-t u* i*er :*!; th;r,:ier. s :> ikt1 K'.ii ,A vir.yliie ' iui-qaer. -The ilrr coal thin* 'ned v. on t'* p" r cent ' vr. & spr.-iai thinner. 'Tut- arc ?: J ufithin* hed coat v.aa ap-' plied offer 2* ` Cost -*t` lacd-*?- f3.fa t-T t*al; fan- r*.7i 0. l' J vr gat IT &< *; of a ' d;j*l;vn' r*--,n. 1*V <U if!'. Of lj- f-ClNi oil. Ill tc of 12> < entlpkiiii; .-Is! r:---Sr<t mhhvr d-n"j*'Cl *n A0 ^ c: !>.-; v* me .(mV *i -ro-n. . *27 icrttf per 1h . IS SO *: of n irri*c.ie * r*s.n . i'K IS vu "i 'i tU 'K . - c:' dir>ji\Al in Ux ` if roat er** *ff^rr.-.aiifni .''.lt`'=s',." .j Greater . than 10 *7 Greater than 10 .'Greater than 10 0.7 Greater than 10 ine, and ozokerite did not give results as satistactnry . those for the waxes reporred in the accompanying table. Ir> the laboratory, beeswax and candeli.'la wax gave resultc simr lar to paraffin. 3 The drying oils -- soy bean, linseed, cottonseed i tung, and perilla - gave- little protection to the concrett The addition of lead and cobalt naphthenate driers to thoi!s irtetcased their Tcsrsrance slightly-. "Ilie oill cspt-i iall, tung oil, did give extra resistance as primer coatings for . resin varnish. H The addition of flee dust, bentonite, infusoria! earth animal charcoal, sulfur, wood charcoal, and basic, calcium lignin sulfonate to the cumar varnish (No. 11) did. no: increase the resistance. . 5 Natural resins, such, as amberol, paranol, and estcgum, made into a varnish with linseed oil and xylol vver not as satisfactory as the average synthetic resin; Yv Stearin pitch was successfully dissolved in a r.uud* of coal tar solvents and drying oils, but these solutions fain as coatings, because they possessed a brittleness that madthem flake oil easilv when the concrete was brushed. CONC.LUStONS *,i *: r-J ri-*h;i* ' cr>l;ut*. ; ,i.rr is in tp *' ' -- -I od ' - *i. m n *f . x.vi-d *iiio t<*al fos* r.i r- > i:i. T7 Grenier than 10 T The most important. consideration with waxes i .their....ease of application. Failures among the waxes ar< mostly due to high melting point; ami ditkcuhv in jpp!-. ing the wax Infore it solidifies. Rapid solidification lead to brittleness and peeling, permitting disintegration to st ir: fvr-* rtfkyd >!xcejlent r r7 . * '. .* .rit-:;i-d niM i-r l<*r ulA in t: r.f the t- t 1 UTTC dw^.lvv.t . 4d X .f .<w1 \ v 1 k- r c i *- vJf .* .i*J. .1 tif . Ji, (Irirr Trr: c Greater tUuniu H-r*- .1>* *tj m ji:.-.rhc> s, _ *- .* 4tl thr 1 V.-C* > ; -. f i (' err li.'.i.; i X- (* si of T-. ^ 12 rtiis. f*er iu -v *i ru,-.`-l cr 1-f lu : : 1!>! a'iivd f. n i 11 a i? e sticks ' t .N . .-!. : < ;** | il'ti sr.-urn he J tnl* -I . I'frlocrn Ihr . i^t i = : - N* -11 r*..? . !-..! -i ld i.a** ',.i ;>r Greater Than l 0.2 4.7 4* Good results were obtained" with-a- mixture of p.ir.uea a: a softer, less brittle wax such as the microcrystdlthe pttre - k-itin by-drov atbons. 2 Asphalt coatings in general arc very resistant rweak acids, but they often cause ensilage to adhere 5 Most rubber-base paints have high acid resist an. The difficulty encountered in their use is the mainten.m-. of a good l>ond between coating and concrete. 4 A .chemically roi-tant resin varnish 'cwvuinir., rlilorinated rubber usually gave good results. Tl-.e resu - penetrates the Concrete and forms a good bond, while tin chlorinated rubber at-the same time gives roughness am: ; extra resistance- to the coating. Tlt v-r.fh r`-i"-rtcd in lh>.s pi[>#r crrivt| or. % IrdtHn-i.l'Ttivrfwv:. tr.l.T 4 x.riinu j h\ th Cj.ivrvta* jsilo (*ot i |mn, r( *:t.li*m1 Ittl:4t:A, ur.l H.;idnr utjhej t.a lh*ni,, Ur Hrc -i.* rt f*r Mi v<- <i ertlnn t. rjinttr'mn W:tti Ut< :u<l>. kVil DSW 325654 STLCOPCB4075696