Evans, Milton, Jr.

English

University of Kentucky

November 22, 1961 MEMORANDUM TO: FROM: J. A. Bitterman Director of Materials W. B. Drake Director of Research SUBJECT: Evaluation of Color Panels Cast from Various Cement Samples c. l. 3. We have used several methods in an effort to evaluate color differences in the 12 concrete panels that were cast in your laboratory. We have brush ed and etched the specimens and have made observations under natural and artificial light. Mr. Milton Evans, Jr., Head of our Concrete Section, has prepared a report on the evaluation. It appears that there is a significant difference in the lightest and darkest panels. Of course, there isyery little difference ·between the three lighhest blocks. I believe that by use of the tables and the accompanying photographs you can determine the range of differences encountered. We do not have available a scientific instrument that will assign actual color values. We think that a "Tri- Stimulus Colorimeter" might provide actual values for color classification. This equipment is rather expensive and we do not have information as to delivery time either. If you feel that the additional information is required, we will try to obtain this equipment. As you know, there are several items that influence the color of portland cement concrete. Mr. Evans has mentioned some of them. We have observed cements having considerably greater variations in color than those represented by the 12 panels. We are of the opinion that color differences of the concrete, particularly in structures, is significant. Consideration could be given to checking the color-match on cements when and if a change of material would be requested. We will keep the panels here for a reasonable time for any additional use that you might find necessary. WBD:dl Attach. : Evans' Memo. cc: A. 0. Neiser < • •  ,_,:'� • •  MEMORANDUM TO: FROM: SUBJECT: November 22, 1961 W. B. Drake Director of Research Milton Evans, Jr. m £, Research Engineer Associate Concrete Color Variations Ob served in Specimens made from 12 Type I Portland Cements c. l. 3. The twelve concrete specimens, provided by the Division of Materials, have been examined to determine color differences. A comparison has also been made among samples of dry cement and among neat cement plates. A copy of Mr. J. A. Bitterman's letter, dated October 17, 1961, which includes a list of sources of the cements, is attached. The 12- x 12- x 3-in. concrete specimens, as furnished, all appeared to be the same color due to the whitish laitance residue on both the formed and trowelled surfaces. In order to expose the true colors of the concretes, the following methods of surfaceprepa:�:ation were employed: 1. One-half of one 12- x 12-in. side was rubbed with a carborundum stone and scrubbed with a stiff­bristled brush, and the other half was left with a formed finish; 2. One-half of the other 12- x 12-in. side was etched with a 10% solution of muriatic acid and scrubbed with a stiff-bristled brush, and the other half left with a formed finish; 3. The bottom edge was scrubbed with a stiff-bristled brush. W. B. Drake - 2 - November 22, 1961 All of the surfaces were observed, wet and dry, under natural light (outdoors) and white £l\f'rescent light (indoors). YeHow, green, red, blue and ultra-violet lights were also used, but these' did not show any differences not observed under natural and flourescent lights. The etched surfaces were compared and rated, wet and dry, under both kinds of light. The rubbed surfaces were also compared and rated under these conditions. The surfaces which were scrubbed with a stiff-bristled brush were still so similar, because of the whitish laitance residue, that no comparison or rating was possible. It is felt that the truest colors were observed when the acid-etched, dry surfaces were compared under natural light. Further, it is believed that exposed structural concrete'would assume this kind of an appear­ance for the greater part of its life (the only difference being that the forces of weather would do the etching on a structure). Although the variation between the lightest specimen and the darkest specimen was very noticeable, it was difficult to rank the in­tervening specimens. Even though there was some variation in the rankings of the specimens (light to dark), depending upon the method used, the four lighter specimens usually showed up in the lighter one third, and the four darker specimens usually showed up in the darker one third. Table I shows the various rankings of the specimens. The dry cement powpers were observed under natural and artificial lights, and they were ranked according to color. Neat cement plates were made from each cement, and they were observed immediately after mixing {plastic condition), fifteen hours after mix­ing (hardened condition) and twenty-one hours after mixing {after oven-drying). In summarizing the color differences among the concrete and cement specimens, average ranks were found for each sample by allowing equal weight for,.ranking positions in each category -see Table II. Average ranking positions were computed by crediting one point for each first rank, two points for each second, three points for each third, etc,., and by summing the points thus obtained in each category for each sample. This was done to determine the degrees of difference between specimens. A mode, indicating the rank in which a specimen occurred most frequejltly, was also found, i.e. specimen No. 6 occurs most frequently as lightest, No. 12 occurs most frequently as ·second lighte.st, No, '10 occurs most frequently as darkest, etc. It can be. seen in Tabtes' I and II that the specimens were not ranked in exactly the same order i.n the different categories, but they are ranked approximately the same. It can be W. B. Drake - 3 - November 22, 1961 seen too ( Table II) that there are recognizable color differences among the cements. For instance, the difference between cements Nos. 6 and 12 is not as great as the difference between Nos. 6 and 10. Photographs are attached to better define .. the various color differences discussed herein. It appears from these observations that a rubbed surface such as results on most of our structures is mostly white in appearance; and, even when different cements are in valved, the color is essentially the same. However, after weathering, this white surface is removed; and the true color of the concrete is then evident. At this time, a dif­ference in color would become pronounced. In any case, where more than one cement is to be considered ' for a single project, color comparisons should be made; and the con-cretes made from the cements selected for the work should be visually matched so as to avoid objectionable color differences. For instance, if the cements analyzed herein were being considered, those cements having nearly the same rank ( Table II) could be allowed a·s alternates; and the risk of getting objectionable contrasts in color would be mini­minized._ It is of equal importance, where color differences of concre,tes I are objectionable, to recognize that a change in the aggregates or even in the mix proportions can effect an appreciable change in the color of the resultant concrete. ME:dl Encs. Figs. 1 thru 4 Attach.: J. A. Bitterman's Memo to T. H. Baker dated 10-17-61, and list of cement brands and code numbers. October 17, 1961 Division of Materials MEllO TO 1 Mr, T, H, Baker Director of Construction SUBJECTs Cement Color Variations A series of tests were conducted in the Laboratory to determine the color variations. Twelve (12) different brands were used (names of brands are attached to this memo). Class "A" Concrete was used in order to make the comparison. The same source of sand and stone was used through-out, Same type of form. form oil and vibrator used by contractors was used in casting these specimens. Actually, color differences among the twelve (12) brands are very slight. All specimens are on display on roof of the Division of Materials Building. PJG/lw Attachment John A. Bitterman Director of Materials .-·> ... ,- .. --, !"··---·-..��· :-,:' C§MljNT MANps 1.I!W. tfAME Of CEM!jNJ BRANP LOCATION 1 Marquette Cement Manufacturing Co,, Cape Girardeau, Missouri 2 Marquette Cement Manufacturing co,, SUperior, Lawrence County, Ohio 3 Universal Atlas Cement Division Fairborn, Ohio 4 Southwestern Portland Cement Co., Fairborn, Ohio (MI. ami) ·5 Volunteer Portland Cement Co., Knoxville, Tennessee 6 Penn-Dixie Cement Corporation Richard City, Tennessee 7 Penn-Dixie Cement Corporation Kingsport, Tennessee 8 Alpha Portland Cement Co., Ironton, Ohio 9 Kosmos Portland Cement Co., Kosmosdale, Kentucky 10 Louisville Cement Co,, Speed, Indiana ll Lehigh Portland Cement Co., Mitchell, Indiana 12 Dundee Cement Co., Dundee, Michigan ' ! TABLE I Color Comparison of 12 Portland Cements Posi- Dry Cement Powder Neat Cement Plates Carborundum Rubbed Acid Etched tions: (2) (3) (4) (5) . Light-to- 1Natura1 2Artificial 1Natural Light 2Artificial Light 1Natural 2Artificial 1Natural Dark Light Light Plastic Hard- Plas.tic Hard- Oven" Light Light Light (l) ened ened Dry Wet Dry Wet Dry Wet 1 6 6 6 6 6 6 6 5 12 6 12 12 2 12 12 12 12 12 '5 12 6 3 5 7 6 3 11 7 5 8 5 12 8 12 5 12 5 5 4 7 5 8 5 8 8 *1 4 7 8 3 3 5 5 8 7 *l 7 *l 3 7 6 3 8 7 6 8 11 4 7 4 7 7 8 8 7 6 8 7 *1 3 3 3 3 3 4 3 4 4 4 ll 8 3 2 *1 4 *l 2 ll 2 *1 9 9 4 9 2 *1 ll 2 11 4 2 $l 9 *l *l 2 10 4 4 2 9 2 9 9 11 10 11 10 9 ll 9 9 9 11 9 11 10 9 2 2 11 *1 12 10 10 10 10 .10 10 X 10 11 10 2 10 � Specimen very rough in texture and difficult to classify. loutside in sunlight. 2Dark Room with only source of light coming from fluorescent (cool white) bulb. x-No. 5 Specimen omitted because of difference in tone (could not be classified because of olive rather than gray tones), a-Omitted from Analysis Table II. Dry 12 7 6 5 11 3 *l 8 4 9 2 10 2Artificial Light Wet Dry 6 12 5 7 12 6 8 5 3 11 7 3 4 *1 *1 8 9 4 11 9 2 2 10 10 TABLE II Color Comparison of 12 Portland Cements ' Position: Average Rank Average Rank Averaf;l:e Rank Light- .Including Columns Including Columns Including to- 2 t 3 � 4 & 5 3, 4 & 5 Column 2 Dark Rank Total Pts. Mode Rank Total Pts. Mode Rank Total Pts. 1 12 27 6 12 23 6 6 2 2 6 29 12 6 27 12, 5, & 7 12 4 3 5 43 5 5 34 5 7 7 4 7 61 8 7 54 8 5 &11 9. 5 8 73 7 8 62 7 5 &11 9 6 3 82 7 & 8 3 66 7 8 11 7 4 107 3 4 87 3 3 15 8 1 110 1 1 94 1 1 16 9 11 120 1 11 110 1 & 4 2 17 10 2 138 9 9 117 9 4 20 11 9 139 9 & 2 2 121 2 9 22 12 10 164 10 10 140 10 10 24 , .. ,_. Fig. 1. Specimens Arranged According to Average Rank. From Left to Right: !.. ight to Dark. Top areas are acid etched and dry. Fig. 2. Alternating Specimens. From Right to Left: Darkest, Lightest, Second Darkest, Second Lightest, Third Darkest, Third Lightest, etc. Most extreme contrast shown on right, descending to least contrast on left. Top Surfaces -- Acid Etched, Dry. ' (_ 10 Fig. 3. Lightest Specimen (ll) and Darkest Specimen (10). Top Surfaces are Acid Etched, Dry. /. (,.:'': t ,�·J z Fig. 4. Lightest Specimen (lZ) and Darkest Specimen (10). Acid Etched, Wet. ('\ \___) Top Surfaces are i� 

Concrete Color Variations observed in Specimens made from 12 Type 1 Portland Cements

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=2287&amp;context=ktc_researchreports

Concrete Color Variations observed in Specimens made from 12 Type 1 Portland Cements

Abstract

Similar works

Full text

Available Versions

University of Kentucky