TRANSPORTATION RESEARCH RECORD 1157

Comparative Study of Chemical Deicers

A. D. MCELROY, ROBERT R. BLACKBURN, JULES HAGYMASSY, AND HENRY W. KIRCHNER

The ice-penetration and ice-melting characteristics of seven volume. All deicers were evaluated over a range of selected commercially available chemical deicers that were tested at temperature and time intervals. This is because penetration is a temperatures ranging from 0°F to 25°F are examined in this measure of a deicer's ability to burrow through the ice and paper. The materials tested included four discrete deicing begin ice/pavement disbonding. The ice-melt volume is a mea­ chemicals and three blends: sodium chloride, calcium chloride, sure of the amount of ice that has been melted and, in conjunc­ potassium chloride, urea, sodium chloride with traces of car­ tion with penetration, is an indication of how much ice under­ boxymethylcellulose, a sodium chloride/potassium blend, and a sodium chloride/urea blend. The ice penetration tests were cutting has occurred. conducted using a Plexiglas™ apparatus consisting of small cavities. Water was frozen in the cavities and penetration TESTING METHODOLOGIES observed when pellets of deicer were placed on the exposed ice surface. The ice-melting tests were conducted using an appa­ At the time this program was initiated, there were no standard ratus consisting of a 9-in.-diameter Plexiglas™ dish containing a 1/s-in.-thick layer of ice. Deicers were placed on the ice methodologies and procedures for specifically testing a deicer's surface at a selected rate. Melt brine was collected, measured, penetration and ice-melting capabilities. Therefore, various and reintroduced periodically with a syringe. The extensive means for carrying out these tests were researched and evalu­ data base resulting from the tests was used to compare the ated. Several approaches were rejected because they lacked several classes of deicers with regard to their ability to melt reproducibility. The testing methodologies ultimately selected and penetrate ice as a function of time and temperature, to provided the type of results that were hypothesized and are establish lower temperature limits for deicer use, and to relate observed behavior to chemical and thermochemical properties fully reproducible. of deicers. An important consideration in the selection of these meth­ odologies was that the tests could be photographed for docu­ There are many manufacturers of chemical-based deicers. They mentation purposes without affecting the test results. The de­ are available for use in several market areas but generally icer particles were treated with a blue dye, Rhodamine B, so compete in the industrial/institutional/residential markets. The that particle penetration and the resultant brine would be visible objective of this research was to obtain valid data on the in photographs. It is believed that this dye had no significant performance of several chemical deicers. effect on the performance of the deicers. A study of the major products was conducted and it was All deicers were stored in predried, screw-cap bottles and determined that four discrete deicing chemicals and three kept inside a glove box until testing time. Special care was blends are primarily used. They are given to hygroscopic deicers in order to prevent them from absorbing moisture. • Sodium chloride, For temperature control, tests were conducted in a 42-in.­ • Calcium chloride, long x 30-in.-wide x 30-in.-high insulated box placed inside a • Potassium chloride, walk-in cold room. This arrangement prevented temperature • Urea, changes caused by the opening and closing of the room's • Sodium chloride with traces of carboxymethylcellulose, access door and body heat generated by researchers. The box • A sodium chloride/potassium chloride blend with 1 per­ was equipped with a hinged Plexiglas™ window that had two cent urea, and hand ports and was completely insulated on all sides. Hand • A sodium chloride/urea blend. ports were equipped with lab jacket sleeves through which the operator's arms were inserted for manipulation of the appara­ Information on these chemical deicers (manufacturer, name, and assay) is presented in the Appendix. Calcium magnesium tuses. Temperature inside the box was controlled by a ther­ acetate (CMA) was also reviewed, but it is not included in this mostat and a small fan which circulated cold air. The cold room research. The test results of this material are discussed in a was maintained at a temperature slightly lower than that of the separate paper in this Record. box. The two major concerns of deicer performance selected for testing were (a) the rate and extent of penetration of the deicers Penetration Test through a layer of ice and (b) the total ice-melting rate and The apparatus developed for the penetration tests consisted of an 11-in. x 2-in. Plexiglas™ plate, 3/s-in. thick in which 15 A. D. McElroy and R. R. Blackbum, Midwest Research Institute, 5 1 Kansas City, Mo. 64110. J. Hagymassy and H. W. Kirchner, The Dow holes were drilled at /s-in. intervals, each /s-in. in diameter Chemical Company, Midland, Mich. 48674. and 11/z in. deep (Figure 1). These holes were countersunk to 2 TRANSPORTATION RESEARCH RECORD 1157

of e~ch cavity. With an aluminum plate, the surface ice was melted but an excess of water was left. The apparatus was again placed in the freezer and allowed to equilibrate to tem­ perature for about 5 hr. Approximately 1 hr before test time, the surface ice was subjected to a final "ironing" with the aluminum plate. At this time excess water was removed and the surface of the ice was made flush with the Plexiglas™ surface. This final surface preparation near the time of the test start effectively sealed the ice/Plexiglas TM interface at the surface. With these precautions, no evidence of preferential melting was observed at the ice/ Plexiglas™ interface. Two particle sieve-sizes were used for each deicer: + 10 mesh and +8 mesh. Twenty to thirty calcium chloride pellets were weighed to determine the average weights for the two mesh sizes. These average weights were then used for all deicers. The weights were 11.5 to 14 mg for the+ 10 mesh material and 22 to 24 mg for the +8 mesh material. If necessary, the sieved, nonhygroscopic deicers were typically filed to achieve these weights. For the sodium chloride/potassium chloride blend, chemical analysis, physical separation, and weighing of the individual particles revealed its composition to be approximately 50:50 by weight. Therefore, particles used in testing this material con­ sisted of one particle of sodium chloride and one particle of potassium chloride, each weighing 6 to 7 mg for the + 10 mesh sample and 11 to 12 mg for the +8 mesh sample. The combined weight of these two materials was equal to the weight of one nonblended deicer. For the sodium chloride/carboxymethylcel­ FIGURE 1 Penetration apparatus. lulose mix, only trace amounts of the carboxymethylcellulose were found. Therefore, the particle primarily used in testing this material was sodium chloride taken directly from the produce an opening 6 mm in diameter and 3.5 mm deep, at the deicer as supplied from the manufacturer's package. point where the cone and the 1/s-in. hole meet. This configura­ One hour before testing, all deicers were brought to the cold tion provides a deicer particle the freedom of movement it room so the materials could reach equilibrium temperature to needs as it begins penetration (Figure 2). simulate actual winter conditions. To ensure that each deicer Degassed (by boiling), deionized water was partially cooled was placed on the penetration apparatus simultaneously, a and placed in the cavities with a syringe and needle, taking care Plexiglas™ caddy was constructed which measured 15 in. long to force out any air bubbles. The apparatus was placed over­ x 2 in. high x 1/2 in. wide. Small cups were drilled in the caddy night in the freezer compartment of a refrigerator. Because and the penetration apparatus was inverted over it so that the water expands when it freezes, a globule of ice formed on top cups and the cavities were aligned; then both pieces were inverted again so that the particles dropped on top of the ice columns. Forceps were used to center each particle over an ice­ filled cavity (Figure 3). The loaded penetration apparatus was 3.5mm immediately placed in position inside the cold box located in =-t the cold room and a timer was started. The penetration depth for each deicer was recorded as fol­ 10 lows. When penetration occurred uniformly and evenly in the 15 cavity, one depth was recorded [e.g., second cavity in Figure 3 20 (15 mm)]. When penetration deviated and tendrils appeared (due to pellet size, density, or shape; the thermodynamics of 25 ice/deicer interaction; or temperature), two depths were re­ 30 corded. The first represented the uniform depth, or the point at

35 which penetration continued to occur uniformly and evenly (Figure 3, fourth cavity, 7 mm). The second represented the '-0 ----'-- maximum depth, or the farthest point reached by a tendril j LI/Bin., 3.17mm ID (Figure 3, fourth cavity, 20 mm). These two numbers were FIGURE 2 Dimensions of added together and the result divided by 2 to obtain the average penetration apparatus. penetration depth (13.5 mm). McE/roy et al. 3

Deicer Next, the dishes were placed on edge in the temperature particles control box and allowed to equilibrate for a minimum of 2 hr. Placing the dishes on edge (a) assured that the dish and ice were exposed principally to the cold air and (b) permitted "'"'5 circulation of the air over and around the specimens causing 10 more rapid temperature equilibration. 15 The deicers to be used for the day's operation were also placed inside the temperature control box before testing and 20 allowed to equilibrate to simulate actual winter conditions. 2..5 Material was taken directly from samples submitted by the manufacturer. The deicer application rate used was 3 oz/yd2 (1,320 lb per lane mile). This rate created amounts of brine from each deicer that were both measurable and manageable at all test tempera­ tures and within the test time limitations. The application rate FIGURE 3 Representative also corresponded to recommendations from the deicer man­ penetration behavior. ufacturers for use as residential/commercial deicers. Samples for the ice-melting tests were taken from bulk Ice-Melting Rate and Volume Test samples of packaged commercial products. Accordingly, parti­ cle size distributions in these samples were representative of There were two primary considerations to the ice-melting test: distributions in package products. The deicer designated as the ability to (a) isolate and measure the brine at various time sodium chloride is commonly known as rock salt or halite. The intervals and (b) return that brine to the ice/deicer system so particle size distribution of this product conformed to ASTM that melting could continue and further measurements be made. Specification D632 for highway deicing sodium chloride (per­ The apparatus used in the ice-melting test consisted of two cent passing: 3/s in., 95 to 100; 4 mesh, 20 to 90; 8 mesh. 10 to pieces of PlexiglasTM, one 1/4 in. thick, one 1/2 in. thick, and both 60; 30 mesh, 0 to 10). The several products consisting chiefly 11 in. square. A hole 9 in. in diameter was cut through the of sodium chloride or potassium chloride (or both) generally 1/2-in.-thick piece. The two pieces were then glued together conformed to this specification, with the exception that most of under pressure, thereby producing a hole 9 in. in diameter and the materials passed a 4-mesh screen. Thus, these materials 1/2 in. deep (Figure 4). Ten dishes were constructed in this contained few of the larger particles commonly present in manner so that simultaneous testing could be carried out. sodium chloride, designated as halite or rock salt. Approx­ imately 90 percent of the calcium chloride particle passed a 6-mesh screen with the bulk of the material being distributed among +8-mesh, +10-mesh, and +12-mesh screens. Essentially all of the urea passed a 6-mesh screen, with the majority being held by 8-mesh and 10-mesh screens. To measure the amount of melt after a specified time period, each dish was tipped so that the brine fiowed to the perimeter of the dish. Using a syringe and needle, the brine was quickly withdrawn and measured. The amount was recorded, then re­ placed in the deicer holes using the same syringe and needle.

RESULTS Penetration Test To ensure accurate and consistent test results, a minimum of three runs were recorded for each time period and temperature level and the average of those results was recorded. After each test run, the cavities were thoroughly flushed and rinsed with FIGURE 4 Melting apparatus. distilled water before preparing the next test. Penetration tests for both + 10-mesh and +8-mesh sieve sizes For each test, the dishes were charged with 130 ml of were conducted at temperatures of 5°F, 15°F, 20°F, and 25°F. deionized water and placed overnight in a level freezer com­ Depths were recorded at 3, 5, 10, 15, 20, 30, 45, and 60 min. partment of a refrigerator. This volume of water corresponded Penetration test results with the +8-mesh-size material are to an ice thickness of 1/s in. Before each test, it was necessary to presented in Table 1 and Figures 5, 6, 7, and 8 as a function of smooth the ice surface. Therefore, a thick aluminum plate was time and temperature. (Note: For simplicity, 3- and 15-min data placed on the ice surface and rotated by hand for several and 3-, 5-, and 15-min data are omitted from Table I and seconds until the surface ice was melted. The dishes were then Figures 5-8, respectively.) The +8-mesh-size material is repre­ placed on a level surface inside the testing cold room until the sentative of the bulk material found within the tested deicers. melted water was refrozen. Consequently, + 10-mesh-size test results are not provided. TABLE 1 AVERAGE PENETRATION DEPTH MEASUREMENTS FOR CHEMICAL DEICERS TESTED AS A FUNCTION OF TIME AND TEMPERATURE

Sodium Chloride Sodium with Chloride/ Sodium Sodium Calcium Potassium Carboxymethyl- Potassium Chloride/ Time (min) Chloride Chloride Chloride Urea cellulose Chloride Urea 25°F 5 2.3 3.6 1.3 1.7 2.4 1.7 2.6 10 3.7 7.2 2.3 2.5 3.6 2.8 4.0 20 8.8 11.9 4.1 4.3 8.4 5.3 8.3 30 13.8 14.3 6.7 5.9 12.8 7.8 13.7 45 18.7 16.5 12.3 7.8 17.7 11.0 18.7 60 21.3 18.5 15.8 9.3 20.8 13.8 20.6 20°F 5 1.1 2.8 1.0 0.4 1.7 1.5 1.1 10 2.3 4.5 1.4 0.9 2.8 2.7 2.7 20 4.8 8.9 2.6 2.0 5.1 4.8 5.1 30 7.8 10.3 3.6 3.1 9.4 7.3 9.0 45 12.0 11 .8 5.2 4.5 14.2 8.8 15.7 60 14.0 13.1 7.1 6.1 16.5 10.7 17.6 l5°F 5 1.4 2.3 0.0 0.0 1.4 1.7 0.9 10 2.2 5.5 0.1 0.1 2.3 3.0 2.1 20 4.2 9.7 0.6 0.7 4.1 5.6 3.8 30 6.4 11.1 1.0 1.4 6.2 8.3 6.0 45 9.9 11.7 1.2 1.6 9.7 10.4 9.6 60 12.2 12.0 1.7 2.0 13.4 10.9 12.5 50F 5 0.9 1.1 0.0 0.0 0.7 0.3 0.8 10 1.7 2.1 0.0 0.0 1.4 0.8 1.4 20 2.2 4.8 0.0 0.0 2.1 1.9 2.5 30 3.1 6.9 0.0 0.0 2.8 3.0 3.1 45 3.8 8.1 0.0 0.0 3.6 4.7 4.0 60 4.7 8.5 0.0 0.0 4.5 7.0 4.9 NoTES: Penetration depth measurements in mm. Deicer particle sieve size: +8 mesh.

Sodiua Chloride Sodium Chloride/ Sodiu• sodiua Caloiua PotllaaJum with Potaaaiu• Chloride/ o:=...,....__;xw~~·_....~,.....~~~ l .... t ""' 11 r~ IL.._ J;ll rlli1lcm . tl£!! 60raln 60mln o.o 1- o. 011ua - O.Omm O,!I lOml!'! 0, 82aun 1,0 lOmln IDmln 1.35111111 l.41111n 1.5 lOmln l.7mm 2Dmln lOmin 20mln 2.0 20mln 2.0Bmm 1. 9nua 2.17mm 2.07mm 2Dmln 2 ,!5 lOmln 2.5lmm JOmln 2.Bmm lDmln ],0 l.Dlmm lDmln J,07mm l. llmm ] • !5 45mln 45min - l.6lmm 45min 4.0 1:e1mm 4.02mm 20mln 60min 4. !5 60min 4.45nun 45min 60min 4,Blmm 4.66min 4.!lmm 5.0 4,7mm 5.5 6.0 6.5 lOmin 60mln 1.0 6.92inm 6.96mm 7.5 45min e.o e.oomm a. !I 60mln 9.0 8,5lmm FIGURE 5 Average penetration depth (mm) at 5°F for No. 8 sieve size. McElroy el al. 5

Sodium Chloride Sodium Chloride/ Sodiu• Sodium Calcium Potaaoium with Potaeoiu• Chloride/ ~_..klu,i;u;;.i.~-_ldl~W!lft...___£hl ;.<.o.._.,r1•., ••nL-_ _,1.,,,ruiA ~ l'.J2Q ltlm.! tllili!!.l..llllil "'oo=-----"-C..._h"'ilg._.r. fl"'rl'A"----~Jr~·· IL___ lOmin lOmin o.o - 0,07mm - O. llmm - 20min 0.5 0.6nua - 20min 1,0 1- lOmin 0,73mm 1- l,Omm - JOmin l. 5 lOmln 45min - 1. 37.mm lOmin IOmln l,O 2.2nua l,2mm 45min - 2. OOm1n 60min - 1. 6mm - 2 . 27mm l.5 l. 7mm 60mln lOmin J,O 2.0mm - 3. Onuo J.5 _ 20rnln 20min 20mln 4.0 4,15nua 4.09mm J. 71mm 4.5 5.0 201nln lOmin 5,5 ·- 5, 6111m lOmln 5, 5m10 - 5. 961111• 6,0 lOmin JOmln - G,2lmm 6.5 6. l7mni 7.0 7.5 a.o lOmin '"-- 8,lmm a.5 9.0 45niin 45mln 9.5 45min 20min 9,7Jmm ,_ 9. 50mm 9.00mni 9,67mm 10.0 45111in 10.5 >-- 10.42mm ~omin - 60min 11.0 il. 05mm l0,9lnua 45min 11. 5 ll.67mm 12. 0 GOmln 60min ,_ 60min 12,0mm 12.5 12, 2 lm1n l2.4011un

ll. 5 liOniln \.l.4"-.. FIGURE 6 Average penetration depth (mm) at 15°F for No. 8 sieve size.

Examination of these data reveals the following: penetrate more rapidly in the early stages (up to 30 min) of penetration events. • At all test temperatures, calcium chloride deicer penetrates Evaluation of the penetration data in terms of effectiveness to substantially greater depths than do the remaining deicers, at under field-use conditions leads to the conclusion that the 10, 20, and 30 min. calcium chloride deicers should be substantially more effective • At 15°F, 20°F, and 25°F, penetration depths achieved by in promoting disbondment of ice from pavement materials. For calcium chloride and sodium-chloride-based deicers are ap­ example, undercutting of a 1/s-in.-thick layer of ice should proximately the same after 45 and 60 min. commence in the following time intervals for the various de­ • At 5°F, penetration by calcium chloride deicer is substan­ icers, considering only +8-mesh-size particles. tially greater than that by the other deicers at all time intervals. • Potassium chloride and urea penetrate little (1.7 to 2.0 Time Interval (min) Temper- mm) at 15°F and, as expected, do not penetrate ice at 5°F. ature (°F) CaC12 NaCl KCl Urea There is a significant difference between the penetration be­ 25 5 10 15 15 havior of calcium chloride and the other deicers, which is not 20 6-7 15 30 30 15 7-8 17-18 >60 >60 indicated by the penetration data. The calcium chloride deicer 5 15 30 - No penetration - tends strongly to melt all the ice above the penetration front. The other deicers tend strongly to produce slender melt ten­ Ice-Melting Rate and Volume Test drils, and thus only partially melt the ice above the penetration front. This difference is consistent with the exothermic heat of Tests were conducted at temperatures of 0°F, 5°F, 10°F, 15°F, dissolution of calcium chloride in water and the slighty endo­ 20°F, and 25°F. The melt volume at each temperature was thermic heat of dissolution of the other deicer in water. This measured at 10, 15, 20, 25, 30, 45, and 60 min. These results fundamental difference in thermochemistry is likewise be­ are presented in Table 2 and Figures 9-13. (Note: For sim­ lieved to be the primary reason that calcium chloride deicers plicity, 15- and 25-min data and 0°F and 10°F data are 6 TRANSPORTATION RESEARCH RECORD 1157

&odlu• Chlorld• &odlu• Chlorld•/ &odlu• &odlu• Calolu• PotaHIU• with Poto .. tu• Chloride/ --'______CIJI ddR-...klll c 111,_J;lll d""---'l'"l~ullR1llll ti ~lsi1llul1111~1 odll"------"raa.__ _

o.o _ IO•tn 0.9- l. 0 I0111ln 1.u- .. , 201aln a.o IO•ln - 2.0in.m 2, llmia IOaln IOaln J.5 01dn - 2.67- 2.61- .u- lO•ln IO•ln LO l,07- 2.Bl- J.5 JO~ln l.6 .... t.0 45•ln I Om In t . 5 20•ln -4.5,.. 20•ln 4.ll- 4.5- 5•ln 20•ln 5.0 - ·.2... s .oa .... s.oa- 5.5 60ooln 1.0 6.01- Ooln 7.0'·' .01- 7.5 1.0 45•1n 1.5 1.u.... 9.0 60aln 10.0'·' 10. 1.... 10.5 11.0 11.s 45mln n.o - 11.97- 13.5 60•ln u.o 11. oe .... U.5 60cdn u.o 11.0.... 451.111• lt.5 14. 11 .... 15.0 15.5 45raln 15. 61111n u.o 60111ln 16.5 16. 45..,, 17.0 6011ln 17.' ll.5it1M 11.0 FIGURE 7 Average penetration depth (mm) at 20°F for No. 8 sieve size.

omitted from Table 2. Likewise, 15- and 25-min data and 10°F dissolution of deicer pellets indicate that all calcium chloride data are omitted from Figures 9-13.) pellets dissolve completely in the early stages of melting tests Examination of the results of the ice-melting tests indicates and that larger sodium chloride pellets are only partially dis­ that the trends and comparative differences of the data gener­ solved at lower temperatures-5°F in particular. ally parallel those exhibited by the penetration data, as enumer­ ated below: CONCLUSIONS • Calcium chloride deicer melts substantially more ice than sodium chloride deicers after 10 to 45 min at 15°F, 20°F, and Penetration Test 25°F. At 10 min the ratio of melt volumes is of the order of 2: 1. At 45 min the ratio of melt volumes is of the order of 1.3: 1. • Calcium chloride deicers initially penetrate ice at all tem­ • At 5°F, calcium chloride deicer melts three to five times peratures, at a rate approximately twice the rates exhibited by the quantity of ice melted by sodium chloride deicers at 10 to other deicers. 45 min, and more than twice the quantity of ice melted by • Sodium chloride deicers penetrate ice at a lower rate sodium chloride deicers at 60 min. • Urea and potassium chloride are inferior to sodium chlo­ initially than does calcium chloride; perform similarly to cal­ ride and calcium chloride at all temperatures and times and cium chloride over a 45- to 60-min period at 15°F to 25°F; and melt little ice at 15°F and none at 5°F. are substantially inferior to calcium chloride at 5°F. • At 60 min calcium chloride is modestly superior to sodium • Urea and potassium chloride are substantially less active chloride at 25°F, and is increasingly superior to sodium chlo­ than sodium chloride and calcium chloride, and they become ride as the temperature is lowered. Visual observations of the essentially nonpenetrating at 15°F and lower temperatures. McE/roy el al. 7

Dodlu• Chloride Sadlu• Chloride/ Sodlua Sodlua C•lolua l'ota••IU• with Pata•alua Chloride/ ____-"-- _ _....1111: dt__.J;J1l d.lltL.....J:bl tld'----11 D~UbllXH tl1tlnUuto11a___i:11 11d.d11.o _ ___, ll:U4- o.o 1.0 1. s 2.0 101dn lOcoln 2. 25 .... 3.5 - l. Sm.11 l.O ],5 lOmin c.o 20!01 n 10,.ln c. oe,.,. 4,25111111 - 4.011111

5,0'·' 2Droln '• - 5.ll- 5,5 lu11ln 6,0 5,92 ... lO•ln '·' I Dia In 6.67 ... 7.0 1.17- 7.5 45,... 10.in 1.0 1. aim 1.11.... 20mln 8. ll1A111 lO•ln '·'t,O I.Bl-

10.0'·' 10.5

11.0 45•ln 11.5 ll.o- u.o 45•ln U.5 l2,l5an

ll.O ll. 5 10-oaln ll, 75- lO•ln 60•ln ll.ll- u.o - H.ll- u.s u.o 15,5 60;oln u.o 15. 75.,. 16.5 17.0 17,5 11.0 11.5 u.o 30.5 60• 1n 60•ln - 20. sa- H,0 - 20.01-

FIGURE 8 Average penetration depth (mm) at 25°F for No. 8 sieve size.

• From the standpoint of undercutting and ice disbondment, ice penetration/undercutting in the early stages (30 min or less) the order of preference is CaCl2 > NaCl > KCl and urea. of ice melting. • Sharp-edged crystal deicers, such as sodium chloride, tend • Potassium chloride and urea are indicated to be substan­ to behave differently than spherical deicers. Spherical deicers tially less effective as expected from theoretical considerations. tend to produce a uniform penetration front; crystal deicers Both are essentially inert at the lower end of the range of penetrate with a nonurtiform melting front with tendrils. temperatures tested in this program. • Deicer blends tested were equal to or less effective than Ice-Melting Rate and Volume Test the sodium chloride at all test temperatures. • Rapid melting of ice/snow in the first 15 min after deicer • At all temperatures and in equal lengths of time, calcium application is critical in determining deicer usefulness. chloride outperformed the other chemical deicers in melt-vol­ ume products. • The performance differences in melt volume increased between calcium chloride and the other deicers as temperature decreased. SUMMARY

Penetration and Ice Melting In summary, calcium chloride appeared to be more effective than the other deicers in terms of ice penetration and melt • Calcium chloride deicers are substantially superior to volume, particularly at lower temperatures and in shorter other deicers, from the standpoint of ice-melting volumes and lengths of time. TABLE 2 AVERAGE MELT VOLUME MEASUREMENTS FOR CHEMICAL DEICERS TESTED AS A FUNCTION OF TIME AND TEMPERATURE

Sodium Chloride Sodium with Chloride/ Sodium Sodium Calcium Potassium Carboxymethyl- Potassium Chloride/ Time (min) Chloride Chloride Chloride Urea cellulose Chloride Urea 25°F 10 6.1 13.8 3.8 4.9 5.3 5.0 6.5 20 13.0 21.4 9.3 6.4 12.7 10.3 13.6 30 19.5 25.3 13.8 8.9 20.1 16.0 2~ . 5 45 24.8 28.9 18.6 11.1 25.2 21.3 26.9 60 29.0 31.3 21.9 12.9 29.6 25.4 30.2 20°F 10 3.0 8.4 1.6 3.6 4.1 5.7 5.7 20 7.8 15.7 3.2 4.8 9.1 8.8 9.9 30 12.3 18.8 6.1 6.0 14.0 12.4 14.8 45 15.8 20.8 8.5 6.6 17.9 16.2 19.5 60 20.2 22.7 11.2 7.2 21.5 18.3 21.8 15°F 10 2.3 5.2 0.4 1.1 2.1 1.8 2.4 20 5.2 11.2 1.0 2.0 4.3 4.7 5.8 30 8.2 14.3 1.4 2.6 7.8 7.6 9.3 45 10.3 15.3 1.9 2.9 10.3 9.7 12.6 60 12.2 16.3 2.4 3.2 12.8 11.8 14.7 5op 10 1.0 4.1 0.0 0.0 0.8 0.5 0.7 20 1.5 8.7 0.0 0.0 1.3 1.2 1.8 30 2.6 10.5 0.0 0.0 2.1 1.8 2.9 45 3.8 11.3 0.0 0.0 3.6 2.4 3.8 60 5.2 12.1 0.0 0.0 4.8 3.2 5.2 NOTES: Melt volume measurements in mi. 2 Deicer application rate: 3 oz/yd •

So

4.0 6Qoli n ,_ ). 7inL 4.5

2Dni.n 6.5 6.lSmL 7.0

7.5

8.0

8.5 lDnin 9. 0 9.llmL

9.5 45min 6Dnin 9.9mL 10;0 lO. l5mL 2 FIGURE 9 Average melt volume (ml) at 0°F (application rate, 3 oz/yd ). Sodlu• Chloride Sodiua Chloride/ Sodium Calolu• Potaeelua vlth Potaaaiua Chloride/ U[§ _J1.._...... _...,i,1il.4..i&lil--'<14-"-i\id~ b 1.,,n...... rl....._ .. n __ -'tl~._r...,•~ e h UnlQ.11,._e __~C h o O 60mln ,_ 60m1n IOmln lOmln o.o 0. OmL 0. OmL 0. 4 5mL o. 6 7mr. lOmln 20mln 1.0 l,OmL l. 2JmL 2Dmin 1.5 20mln lOmln 1. 77mL l. SJmL l.BmL 2.0 45mln lOmln lOmln 2.5 2. l7mL 2.07mL 2.6lmL GOmln J,0 45mln l.2mL 45mln J.5 45m1n J. 57mL J.BJmL l,BmL lOmin 4,0 4.lmL 6Dmin 4,8lmL 60min 5.171nL !5.0 6Dm1n S. 2JmL !!.!!

2Dmln 8.5 - 0. 67onL 9.0 9 .!! 10.0 lOmin 10.5 l0,5mL 11.0 45m1n 11. J2mL 11.5 J.2. 0 _ 60mln u.!5 12. lJmL 2 FIGURE 10 Average melt volume (ml) at 5°F (application rate, 3 o7lyd ).

Bodlu• Chloride Bodiu• Chloride/ Sodlu• 8odlu• Calolu• PotHaiu• vlth PotHalu• Chloride/ _...._,,...--__..,.....-¥ ~. ~WJ•J~d1.110 __..i.Vrµi11-_..i...11t .llil.au •iJc11\111lQ1,.p__ __.c ... 111Ql'.1.!1._ ____u.._

o.o 1011ln 0.4•L lO•ln 1.0 2011ln - .OlmL l.OlmL lO•ln IOaln 1.5 lOml n l. Blm.L lOn1l11 201al11 2.4211L a.o l011ln 1. 4mL .O• L 2.08mL 2,25•L 45gln l 011ln 2.5 l,9mL - 2. 6lmL l.O 60ooln Smln 2. l7mL .. 9JmL l .11 Oraln 4.0 • llmL 20odn 4. llmL 2011ln 4.5 2011ln 4, '7• L 5.0 5, l 711L 10Gln 20mln 5.2lmL 5.5 5. 7511L "",...., 7.0 JOmln loaln 7.5 l.6l11L 7,58mL IO•ln a.o • l 711L 1.5 JOmln 9.0 9.llmL 45mln 9.5 9,6711L 10.0 S11ln 45mln 10. ll111L 10.!I l0.25NL 2Dmln u.o 11.lBmL 60mln 11. !I ll. l7mL · 01dn u.o 45mln u.s l2. l7'"L 601.tn 12. SUmL 12,DlmL u.o ll.5 u.o l01dn 60roln u.' 14. 25mL - l4.67mL l!I. 0 45mln 15.5 15. 251aL 60mln u.o l6. ll1>L U.!I 2 FIGURE 11 Average melt volume (ml) at 15°F (application rate, 3 o7lyd ). Sodium Chloride/ Sodium eodiu1t Caloiu111 Potaeeiu111 Potaeeium Chloride/ ----'~.--~hl 2r ll h »•.....,"------"

Bodlu• Chloride Bodlua Chlorld8' Pot•••lua vlth Potaaalu• ,-1iu'--->c.,.1o'"l"'••u11'•'tt___ll ~dul•~ atJ tit,allilloao C!U dll~---"' o.o l. 0 2.0 l.O 4.0 - aoaaln l,81 ..L - 10.. ln o.o 4. 07o11. I0111ln l011ln I Om In ~.O&QL 5, lll8L 6.0 6,0810L lOniln 10 .. 1n - G,491nl, 1 .0 6, tl1ML 1.0 _ 1011.ln •. o lO•ln U, 92mL lOmln 10.0 - ~.lloaL H•ln ID. ll"L ll. 0 11. loaL u.o - 20mln 20mln GOraln - L2,9l1nL U,6h1L n.o 12.91•L ,zo ... t n ,___ lOmln tOillln ! l. 5 5,.1, u.o ll. ll11L - I l.llmL u.o u.o lOmln 16,0IAL 17.0 u.o _ 1s .. 1n 8, 6,.L u.o 1Dmiln .l011ln 20. o 19.011L 20.0710L 31.0 45,.ln 21, ]J,.L ai.o 3],Q J4,0 bo111n 35.0 -~5.l l•Li - 45•1n 6D•ln 2~.lllOL 25, 41aL 36.0 H.O aa.o 60mln ,_ 45aln 601dn a.o 29,0IOL 2i,92m~ 29,5DaL G01ai n l0,0 - 10. llh•L 6Dmln l l. 0 - JI, 2111L H.O 2 FIGURE 13 Average melt volume (ml) at 25°F (application rate, 3 oz/yd ). McElroy el al. 11

APPENDIX Sodium Chloride with Carboxymethylcellulose Manufacturer: Morgro Chemical Company Sodium Chloride Trade Name: Ice-Fighter Plus™ Assay: 99 to 100 percent sodium chloride Manufacturer: Morton-Thiokol, Inc. with traces of Trade Name: Halite Safe-T-Salt™ carboxymethylcellulose Assay: 99 percent sodium chloride Sodium Chloride/Potassium Chloride Calcium Chloride Manufacturer: Koos, Inc. Manufacturer: The Dow Chemical Company Trade Name: Safe Step™ Ice Melter Trade Name: PELADOWTM calcium chloride Assay: 44 percent sodium chloride, 54 pellets percent potassium chloride, 1 Assay: 90.8 percent calcium chloride percent urea by assay; physical separation of particles: 51.5 Potassium Chloride percent potassium chloride, 48.5 Manufacturer: Howard Johnson Enterprises, Inc. percent sodium chloride Trade Name: Zero Ice™ Melting Crystals Assay: 99 percent potassium chloride Sodium Chloride/Urea Manufacturer: Chemop harm Urea Trade Name: Superior Sno-N-Ice™ Melter Distributor: Lange Stegmann Assay: 92.5 percent chloride, 5.3 percent Principal Fertilizer grade urea, spherical urea by assay; physical separation Ingredient: particles of particles: 93 to 94 percent so­ Assay: 100 percent urea dium chloride, 6 to 7 percent urea