Thermoplastic Striping Compounds

Transcription

1 49 Thermoplatic Striping Compound C. J. KEE, Reearch Aitant, and FRED J. BENSON, Reearch Engineer, Texa Engineering Experiment Station SYNOPSIS IN 1949, the Texa Engineerlog Experiment Station inaugurated a reearch project to develop a compound for triping pavement which would produce tripe with longer ervice life than thoe now in general ue. The Road Reearch Laboratory in England during World War n developed a atifactory triping compound of a mixture of roin, mineral oil (a platicizerfor the roin), pigment, filler, and and. The mixture i heated to 135 C and placed, wlille hot, to a thickne of about 1/8 in. Stripe laid in Texa in accordance with the Britih formulation proved to be too oft, were ubject to rather evere dicoloration by the adheion of road dut and tire film to the urface of the tripe, and howed poor adheion to portland-cement concrete. But the reult were ufficiently encouraging to warrant a deciion to tudy modification of the Britih formulation. The triping compound produced by adding alkyd rein to the roin-platicizer mixture ha hown excellent characteritic. The tripe doe how dicoloration under traffic, and tudie are currently under way in an attempt to improve thi characteritic. The roin triping compound ha been rated for ervice life by laying tranvere tripe on aphaltic-concrete and portland-cement-concrete pavement. Gla bead have been incorporated in part of the tripe. Four of the roin-bae tripe have been in ervice for 12 to 14 month. Eight roinalkyd rein tripe have been in ervice for 6 to 8 month; and a large number of other have been in ervice for leer period of time. Reult to date indicate that the roin-bae tripe will have a ervice life of two to three time that of the comparative paint tripe. Ingredient in the roin-bae tripe are uch that the cot of the material compare favorably with the cot of paint. IN FEBRUARY 1949, the Texa Engi- and covering it with a layer of uniformly neering Experiment Station (a part of the graded aggregate. Texa A and College Sytem) Initiated When thi i contructed with limea reearch project to develop a emi- tone, a rather good white tripe i permanent center tripe for highway ue. produced. Thi type of tripe ha been Study of the triping problem in Texa and ued for a number of year by everal dicuion with engineer of the Texa highway department and ha proven to Highway Department indicated that a have a very long ervice life. The method highway tripe with a ervice life of 3 to of triping ha two diadvantage: the 6 year which could be placed at low cot night viibility of the tripe i quite poor wa the deirable goal. Invetigation of and no naturally yellow tone i available the literature and letter contact etab- for producing tripe in the tandard lihed the fact that many individual and yellow color. Therefore, it wa decided concern were working with paint tripe to attempt to color limetone yellow in in order to improve durability. It wa order to atify the econd ob'^jection to decided that the invetigation would be the ue of the builtiqi tripe. None of the directed primarily toward material other attempt to do thi wa ucceful. The than paint for triping. method which howed the mot promiing The firt poibility conidered for pro- reult wa thatof forming lead chromate, ducing a emipermanent tripe wa the an inoluble yellow pigment, in the pore builtup or urface-dreed type, produced of the limetone by a chemical reaction, by laying a binder layer of aphalt cement Good color wa produced, but thepenetra-

2 5 Figure 1. Laying roin tion into the tone wa not ufficient to give practical ervice life. The econd poibility invetigated wa the ue of hot-melt platic compound which would harden upon cooling and thereby produce a permanent line on the pavement urface. The Britih had developed uch a tripe by combining wood roin, platicizingoil, pigment, filler, and and. Thi mixture wa heated to 135 C, thoroughly tirred, and laid by creeding it on the pavement with a mall creed box having an adjutable gate. The thickne of the material a laid wa about 1/8 in. The Britih report indicated coniderable ucce with thi type of tripe. Their experience howed a ervice life of approximately two year and an initial cot of about twice that for paint tripe. Since thi wa the only ucceful hotmelt platic tripe which the tudy of the literature uncovered, the deciion wa made to begin the invetigation by tudying the Britih tripe. triping corr.pound. INTERI RECOENDATIONS COPOSITION LINE OF PLASTIC FOR T H E WHITE COPOUNDS' Gum roin 15 percent by weight ineral oil (vicoity 1/2 to 2 poie at 25 C) 5 percent by weight Titanium dioxide.. 1 to 5 percent by weight Extender (whiting, etc.).. 1 to 15percent by weight Aggregate (and)... 6 percent by weight On July 28, 195, a tripe.wa laid in accordance with thi pecification. It wa found to be too oft for the 'hot Texa ummer, ince the traffic rolled it out, and the adheion of road dut and tire film to the oft material oon changed the color to very nearly that of the pavement. 'Crown copyright reerved Publihed by permiion of the. Director of Road Reearch, Road Reearch Laboratory, HarmDndworth, iddleex, England.

3 51 TAHE 1 COPOSITION OF ROSIN-OIL SERVICE TT STRIP INGREDIENTS (Percent by Weight) Stripe ineral Ti tan mm Ch f oitie Calcium Concrete Number Roin Oil (TiCa) Whiting Yellow Chromate Sand (edium) B B B B SILICA (LITONE) R R R-3 2i ODIFICATIONS OF BRITISH COPOUNDS In order to produce a harder tripe, the amount of platicizing oil in the compound wa reduced. A number of oilroin combination were tried in the laboratory with the hardne of each compound being meaured with the tandard penetration ^paratu for aphalt and the brittlene being meaured by mean of a cold-bend tet The proper oil content wa elected a 2 to 8 percent of the weight of the roin-oil mixture, or an oil content of. 5 to 2 percent of the weight of the total mixture. Laboratory tet in which the TABLE APPLICATKS^ DATE ON ROSIN-OIL TT STRIP pigment, filler, and and were varied indicated agreement with the Britih interim pecification with regard to proper proportion of pigment filler and and. Yellow color wa produced quite uccefully by the ue of chrome yellow alone or with calcium chromate a pigment Four tet tripe uing the compoition elected a having deired hardne and brittlene characteritic on the bai of the laboratory work were laid in Augut and October of 195. Thee tet tripe were laid tranverely acro half of the roadway in order to get maximum traffic effect. The tripe were laid at the ame Stripe A P P L I C A T I N >ndition Number Color Date Temperature Tliick ne Time Protected When Opened F. in From Traffic to Traffic Anhalt Surface Area 1 min. B-2 8/15/ Hard-High Glo B-3 8/15/ Hard-Slight Tack B-4 1/13/ Hard-High Glo P-4 7/25/ Hard-Dry to Touch P-5 7/25/ Dry-Soft-Slight Concrete Surface Area Tack B-5 1/17/ Hard-High Glo P-8 8/1/ Soft-Slight Tack R-1 6/27/ Hard-Dry R-2 6/26/ Hard-Dry R-3 * 6/26/ Hard-Dry P-4 Chlorinated rubber traffic paint P-5 Pliolite traffic paint P-8 Pliolite traffic paint (Texa Highway Department Specification YP-3) Control paint tripe X-1. X-2, X-3, X-4 Table 9. Oncrete urface area 4 Yellow White

4 52 TABLE 3 ONTHLY HATING OF ROSIN-OIL TT STWP t-4 o m m a 4J tn hi V u h > ja ) ) e ) S 4J i V 1 V JQ B a 9 (Q w ja 4J o 9 u H t> 9 U) a. > u B e U) a. *i *i a> u o A) a ^ a a (B 9 9 U U < O z Q»-5 S -I O o < < * B-2 N S * N S B-3 S S S S * B-4 N N S S * N N S S * P-4 {W)C N N S S N S * P-5 C S S S S * S S S S Location Area 2 Pavement Sur face * Portland Cement Concrete B-5 N S S P-8 C S S Location: Area 4 'avement Sui face. Concrete R-1 5 N S R-2 1 N S R-3 N Noticeable cracking of film. RATINGS- Film lo in percent. Dicoloration- (N) none; () moderate; () moderately evere, (S) evere, () extremely evere (C) Control paint tripe Yellow White er Se

5 53 location a two paint tripe which had been laid the latter part of July 195. Gla ref lectorizing bead were applied to aportionof each tripe. The tripe were rated the firt of each month by viual examination on the bai of film lo and dicoloration. The percentage of expoed pavement within the area originally covered by the tripe wa etimated and recorded a film lo. The dicoloration of Figure 2. Stripe a laid in Bryan, Texa. Fioin tripe i at right and (Texa) tandard YF-7 paint tripe i at left. Figure 3. Stripe hown in Figure 2 after 5 month' ervice. Paint tripe wa repainted twice. TABLE 4 COPOSITION OF ROSIN-ALKYD RIN SERVICE TT STRIP Ingredient (Percent by Weight) Deig Roin Alkyd Plati- Lead Cobalt Titan Whit Silica Chrome Calcium Con Lime Ottawa Cruhed nation Rein cizing Drier Drier ium ing Hller Yellow Chro crete tone Sand Lime Oil (24%)* (6%)* (TiCa) (edium) mate Sand Sand tone ( ) BA-l Eft BAr BA it.'' B\ ' ;". BA BA BA ' 'i; 5 61 BA BA i- 7..,: K) 1 56 BV , BA a\ V * BA Percent metal baed on alkyd rein.

6 54 TABLE 5 APPLICATION DATA ON BOSIN-ALKYD RIN TT STHIP Location: Area 4 Pavement Surface Portland cement concrete Stripe No. Color Date Temp. F. Thickne in. Time Protected from Traffic mi n. Condition When Opened to Trafflr BA-5 (V) 6/27/ Hard-Dry BA-7 6/27/ Hard-Dry BA-1 6/18/ Hard-Dry BA- 13 7/1/ Hard-Dry BA-14 7/1/ Hard-Dry X-l(C) 6/19/ Dry X-2(C) 6/19/ Dry X-3(C) 6/19/ Dry X-4(C) 6/19/ Dry BA-15 7/17/ BA-17 7/26/Sl Slight Tack BA- 18 7/24/ No Tack BA-19 7/24/ Hard No Tack X-1 Texa Highway Department YP-7 (Alkyd) X-2 Texa Highway Department YP-7 (Alkyd) X-3 Texa Highway Department YP-3 (Pliolite) X-4 Texa Highway Department YP-3 (Pliolite) Location TABLE 6 APPLICATION DATA ON ROSIN-ALKYD RIN TT STPIP Area 1 and 3 Pavement Surface Area 1 Aphaltic Concrete Area 3 Portland Cement Concrete Stripe Color Date Temp. Tliickne Time Protected Condi tion No. F. in. from Traffic When Opened min. to Traffic P-16 P-17 BA-1 BA-2 BA-3 PA-4 EA-8 BA-11 3/22/51 3/22/51 4/27/51 5/5/51 5/5/51 5/1/51 6/28/51 7/6/ None Dry to Touch Dry to Touch Hard Surface Soft Soft Hard Surface Hard Surface Slightly Soft P-16 Commercial traffic paint, beaded P-17 Commercial traffic paint, beaded the paint tripe wa rated by comparing the color of the tet tripe with that of a ample of the triping material placed on a block of imilar pavement material. Dicoloration wa rated from "none" to "extremely evere" (indicating a color very nearly that of the pavement urface). Colored photographic print, which were taken at the time of each rating, clearly record the extent of film lo and dicoloration. Black and white print record film lo but do not indicate dicoloration. Table 1,2, and 3, how the compoition, application data, and monthly rating of the roin tripe and paint tripe ued for comparion. In everal intance, the tripe how an improvement in the dicoloration rating. Thi improvement i due to the wahing action of rainfall and the chalking action of the pigment.

7 55 ROSIN-OIL STRIP AND CONTROL PAINT STRIP Aphalt Surface - Area I B-2 (Roin-Oil Stripe). Thi tripe gave an excellent appearance for a few month. The dicoloration by the adheion of road dut and tire film wa at time o evere that the tripe had a color very nearly that of the pavement urface. Crack appeared in January and became evere during the ice torm in February, during which a low temperature of 5 F wa recorded. Even though thee crack extended completely through the tripe to the pavement, no film lo ha been oberved, and after 14 month of ervice, the tripe i till effective. B-3 (Roin-Oil Stripe). Thi ofter tripe ha hown intenive dicoloration from the beginning but wahe clean during rain to a color very nearly that of the original color. After 14 month of ervice, it how no ign of cracking or noticeable wear. B-4 (Roin-Oil Stripe). Thi yellow tripe contained a harder binder than tripe B-2. Cracking wa more evere, and thee crack widened to the extent that a film lo of 1 percent had occurred after approximately 12 month. Dicoloration ha not been a evere a for tripe B-2. TABLE 7 ONTHLY RATING OF ROSIN-ALKYD RIN lt STRIP Area 1 Aphaltic Concrete Pavement April (1951 ) ay June July Augut September October October 15 P-16C * S P-17C 1 5 1' S BA-1 S S S * S S S BA-2 («) S S S S S * S BA-3 S * S BA-4 * S S S BA-8 N S BA-11 b S 4 percent lo of bead Rating: Film lo (percent) Dicoloration (N) none, () moderate, () moderately evere, () extremely evere. (C) control paint tripe. yellow. white. (S)

8 56 TABLE 8 ONTHLY RATING OF ROSIN-ALKYD RIN TT STRIP Area 3 Poitland- Cemen t -Concrete Pavement P-16C P-17C April ay June July Augut September October October 15 (1951) S S S BA-1 BA-2 BA-3 BA-4 BA-8 N * BA-11 'Indicate approximately 4 percent of bead aborbed into tripe. Rating: Film lo (percent) Dicoloration: (N) none, () moderate; () moderately evere, (S) evere, ()Extremely evere. (C) &>ntrol paint tripe. Yellow. White. *» * N S S S S 5 S P-4 (Paint Stripe). Film lo became noticeable over mooth urface of protruding aggregate after only one month of ervice. The color of the tripe wa good except in the area where reflectorizing bead were applied. Film crack were oberved in the pring of The effective life of the tripe wa conidered to be 7 month. P-5 (Paint Stripe). Dicoloration wa evere and film lo over protruding aggregate wa noticeable at the time of the firt rating. Film crack were oberved in the pring of The effective life of the tripe wa conidered to be 1 month. Concrete Surface - Area 2 B-5 (Roin-Oil Stripe). Lo of adheion and reulting film lo wa rapid. Failure of the tripe began during the firt freezing weather in December and wa complete in January. The tripe did not dicolor a everely a the ame compoition on the aphalt urface. P-8 (Paint Stripe). Dicoloration wa evere from the beginning, epecially in the beaded portion of the tripe. Film lo in mall evenly ditributed pot wa noticeable at the time of the firt rating. The effective life of the tripe wa conidered to be 4 month.

9 57 R-I (Roin-Oil Strjpe). After only a light amount of rainfall, air bubble or bliter appeared over the urface of the tripe. Thee bubble were initially ironed out by traffic with only mall urface deformation. During the cooler weather of September and October, thee bliter were broken by traffic. Thi reulted in a pitted urface on the tripe. Small area of the tripe have lot adheion to the pavement and have flaked off. R-2 (Roin-Oil Stripe). The ame general pattern of blitering ha been oberved a for R-I above. Small area of the tripe have flaked. R-3 (Roin-Oil Stripe). Thi ofter tripe ha hown ome blitering and reulting bliter hole, but blitering ha not been a evere a for tripe R-1 and R-2. The initial work with the roin tripe indicated the following three major difficultie in it ue: (1) The Roin-oil tripe had poor adheion to concrete. (2) The proper balance between hardne and brittlene in the triping compound wa difficult to achieve; oft tripe were deformed and dicolored by traffic, wherea hard tripe were too brittle and cracked everely in cold weather. (3) The tripe howed exceive dicoloration due to the adheion of road dut and tire film. The experimental work performed in the period from September 195 to the preent time ha been primarily directed toward producing a roin tripe which would overcome the difficultie indicated. Tet were firt conducted with twelve chemical and oil platicizer to replace the mineral oil. The reult, baed on the performance of the tripe under traffic, indicate that chlorinated paraffin and chlorinated diphenyl oil are better platicizer than mineral oil. Attempt were made to incorporate both natural and ynthetic rubber in the roinoil compound. Natural rubber wa incorporated in the form of finely ground rubber crumb. Examination of laboratory ample containing thee crumb howed the mall rubber particle to be evenly divided throughout the mix, indicating that the rubber did not often ufficiently to blend with the binder material. A uniform blend wa obtained with ynthetic rubber, but the reulting compound were ticky and hard to pread. The urface of the pread material did not hardenproperly after the material had cooled. The incorporation of alkyd rein in the roin triping compound wa found to materially improve adheion, hardne, and flexibility of the tripe. Thi modification of the Britih compoition ha hown the mot promie, and an extenive tudy of the roin-alkyd rein compound wa tarted in February of ROSIN-ALKYD RIN STRIPING COPOUND Laboratory tet on binder compound containing alkyd rein indicated that atifactory hardne and brittlene wa obtained by the incorporation of from 1 to 16 percent alkyd rein and noplaticizer with roin, or with 1 percent alkyd rein and from 1 to 4 percent of oil platicizer. Seven roin-alkyd rein compound containing no platicizing oil have been laid a tet tripe on variou treet of the A and College of Texa campu. Thee tripe are deignated BA-1 through BA-5, 1, and BA-15. A number of tripe have alo been laid which contain roin-alkyd rein-oilplaticizer binder. Of thee, five have been in ervice long enough to be reported at thi time. Thee tripe are numbered BA-7, 8, II, 13, and 14. A cobalt-metal drier wa added to the roin-alkyd rein triping compound in order to harden the urface of the tripe and thu prevent dicoloration due to the adheion of foreign matter. Three of thee tripe have been in ervice almot three month. They are tripe BA- 17, 18, and 19. The compoition of the roin-alkyd rein, roin-alkyd rein-oil, and roinalkyd rein-oil-drier tripe i hown in Table 4. Roin-alkyd rein ervice tet tripe were applied to the pavement in three location. The application data and monthly rating of thee tripe and the paint control tripe ued with them are hown in Table 5, 6, 7, 8, and 9.

10 58 TABLE 9 OHLY RATING OF ROSIN-ALKYD RIN TT SIRIP Arpa 4 Portland-Cement-Concrete Pavement July 1951 Augu t Sep tember October October 15 Remark on final rating BA-5 5 Bliter hole N S - BA S S S BA S BA-13 No bliter S BA-14 S X-1 Black X-2 2 X-3 1 X-4 S BA BA-17 PI ain Some Bliter S BA-18 EA Bliter Hole S Some Flaking Greenih color RATINGS Film Lo (Percent) Dicoloration (N) none, () moderate, () moderately evere, () extremely evere. Yellow White (S) ROSIN-ALKYD RIN STRIP AND CONTROL PAINT STRIP At the time of thi report, the oldet of the rom-alkyd rein tripe have been in ervice for only 5 V2 month. The weather during thi period of time ha been generally hot, and there ha been only a mall amount of rainfall. All of the roin-alkyd rein and roinalkyd rein-platicizing oil tripe have hown good adheion to both portlandcement-concrete and aphaltic-concrete pavement. Thee tripe have all been ubject to dicoloration by the adheion of road dut and tire film. Dicoloration of thee tripe ha been about the ame a for the roinoil tripe dicued earlier. The incorporation of metallic drier ha only lightly reduced dicoloration. In the ue of paint tripe for com-

11 59 parion with roin triping compound, the following point have been oberved: (1) Failure of paint tripe film ha occurred becaue of lo of bond or adheion to the pavement. (2) Dicoloration of paint tripe in ome cae ha been very nearly a evere a for the roin compound tripe. (3) Dicoloration of the portion of each paint tripe beaded with gla ref lectorizing bead ha been more evere than for unbeaded ection; thi dicoloration ha materially reduced day viibility of the tripe. Several paint tripe, not reported in thi paper, have been beaded in alternate 6-in. ection. Thi method of bead application greatly improve day viibility without materially reducing night viibility. CONCLUSIONS Although ome of the triping compound reported in thi paper have been ervice teted for a relatively brief period of time, the following general concluion appear to be jutified: 1. Yellow and white tripe compounded according to the pecification for the Britih "Platic White Line,"modified by the reduction of oil content, have hown good ervice life on aphalt pavement. Comparion with tandard paint tripe indicate a relative ervice life of more than 3 time that of the paint tripe. The undeirable characteritic of thi material are (1) poor adheion to concrete pavement and (2) dicoloration by the adheion of foreign matter. 2. The incorporation of alkyd rein in the roin compound materially improved adheion of the triping material to portland-cement concrete but did not materially reduce dicoloration. The roin triping compound modified by the addition of alkyd rein ha very definite poibilitie a a triping material. The hort drying time of from 5 to 1 min. i a definite advantage in it ue. ACKNOWLEDGENT Content of thi paper are baed on Project No. 192 (Development of Semipermanent Center Stripe for Highway Ue) of the Texa Engineering E^eriment Station. Under thi project, adheive material and dye were invetigated with repect to their luminoity, reitance to abraion, and weather reitant qualitie. By permiion, ome data of the Road Reearch Laboratory, Harmondworth, iddleex, England are ued and dicued in thi paper. Appreciation i expreed to the many companie and individual who generouly gave information and material for the e;q)eriment. Special mention i due the following peron: Dr. A. R. Lee, Road Reearch Laboratory, Harmondworth, iddleex, England; Lawrence Ortolani, aterial and Tet Engineer, Texa Highway Department; arhall Brown, Reearch Engineer, Texa Highway Department; K. K. oore, Paint Engmeer, Texa Highway Department; Harry A. Sandberg, Aphalt Engineer, Texa Highway Department; C. W. Chaffin, Semor Chemical Engineer, Texa Highway Department; R. E. Workman, Chemical Diviion, Goodyear Tire and Rubber Co; and J. F. O'Neill, Chemical Product Diviion, Goodyear Tire and Rubber Co.