NBSIR 78-1449

The Effects of Herbicides on

Masonry

James E. Fearn

Structures and Materials Division

Center for Building Technology

National Engineering Laboratory

National Bureau of Standards

Washington, D C. 20234

Final Report

May 1978

Sponsored by

The National Park Service

U.S. Department of the Interior

Washington, D.C.

NBSIR 78-1449

THE EFFECTS OF HERBICIDES ON

MASONRY

James E. Fearn

Structures and Materials Division

Center for Building Technology

National Engineering Laboratory

National Bureau of Standards

Washington, D C. 20234

Final Report

May 1978

Sponsored by

The National Park Service

U.S. Department of the Interior

Washington, D.C.

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Dr. Sidney Harman. Under Secretary

Jordan J. Baruch, Assistant Secretary for Science and Tachnoiogy

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

THE EFFECTS OF HERBICIDES ON MASONRY

James E. Fearn

Abstract

In preserving historic structures, the control of obnoxious vegetation is

a serious problem. To deal with this problem, a number of organic herbicides

have been developed by industry. The efficacy of herbicides in the control

of plant life has been studied to a great degree, but heretofore, very little

has been reported about the possible effects of these chemical plant killers

on the materials they are supposed to protect. In this work, an exhaustive

survey of pertinent literature was undertaken. Obtaining very little specific

information from literature, a correlation has been drawn between the effects

on masonry of materials similar in chemistry to herbicides and the effects

that would be expected from the herbicides themselves. Methods for checking

the validity of conclusions are suggested.

Key words: acidic, alkaline, degradation, herbicide, historic structures,

masonry

.
1. INTRODUCTION

1.1 BACKGROUND

The destructive effects of vegetation on artistic or historic structures

are a serious concern to those entrusted with their care. This is true

both in this country [1]^ and abroad [2-5]. Damage may be caused by such

simple plants as algae, fungi, lichens, and mosses, or by the more

sophisticated flora commonly referred to as weeds. The damage may result

from water retention by foliage, the weakening of mortar joints through

penetration and proliferation of roots [2], or through chemical attack

by certain secretions of the plant.

The usual method of combatting pernicious vegetation is by repeated cutting

and clearing but in areas of alternate bright sunlight and heavy rainfall,

where the growth rate of plants is particularly high, chemical control

may be competitive with the older methods. Unfortunately, uncertainty

about the effects of the chemicals on masonry makes difficult the assessment

of the risk of using herbicides while it is known that careful cutting

and clearing is safe and effective. The National Park Service is interested

in the use of herbicides to help in the difficult and costly task of

controlling vegetation in the immediate vicinity of a series of forts built

along the Gulf of Mexico. Because of the uncertainty of the long-term effect:

of herbicides on the masonry of these forts the National Park Service

asked the National Bureau of Standards to carry out the survey covered

in this report.

1 Numbers in brackets refer to the literature references listed at

the end of this paper.
1.2 OBJECTIVES AND SCOPE

1.2.1 Objectives

1. To survey and assess the state of knowledge regarding the effects of

herbicides on masonry structures and to present preliminary recommendations about the use of herbicides.

2. If deemed necessary in the light of the results to prepare a comprehensive research plan for evaluating the effects of herbicides on masonry

structures

.

1.2.2 Scope

While the study was begun to provide information concerning the effects

of commercially available herbicides on the masonry of the Gulf Coast forts,

general considerations of the effects of herbicides on masonry of all types

have been included in the hope that they will assist all who are faced

with the task of protecting artistic or historic masonry structures from

the destructive effects of vegetation.

This report is organized in such fashion that the range of masonry materials

is discussed first (Chapter 2), followed by a brief review of what is

known about the degradation of these materials or their constituents by

chemicals (Chapter 3). Next, the compositions and natures of the most

common types of herbicides are reviewed (Chapter 4), and the possible effects

of herbicides on masonry materials considered from the chemistry of these

materials (Chapter 5). In Chapter 6, preliminary criteria for selecting

herbicides for use on masonry are presented along with commentaries on

research which may be carried out in improving the technical bases for

the criteria and reducing them to their most conveniently useful form.

Finally, a summary of the report with recommendations concerning the

3
use of herbicides on artistic and historic masonry structures is given

in Chapter 7.

2. MASONRY MATERIALS

2.1 MASONRY UNITS

Masonry units are of many kinds, differing widely in appearance and

durability. They include many types of building stones (table 1) [14],

clay brick, clay tile, terra cotta, cinder block, concrete block, adobe,

etc. Clay brick, which was developed by potters prior to the building

of King Soloman's temple [6], during the tenth century before Christ, may

vary widely in durability and other aspects of performance because of differences in raw materials and manufacturing processes. This is true of

manufactured masonry units in general. Variation in building stones results

from differences in the natural processes by which they were formed. At

the time of the building of the Gulf Coast forts in the mid-nineteenth

century, the lack of consistency in the quality of brick was a major problem

[7]. It is therefore not judicious to consider modern clay brick an adequate

model for the brick used in constructing the forts. The ability of brick

and other clay products to resist weathering depends to a considerable

extent on their porosities, which vary widely depending on the specific

nature of the original clay and the method of fabrication [6] (see table 1).

An excellent book by McKee [17] traces beautifully the development of the

brick industry in America from 1610 to 1758. Norton [18] also deals with

such important aspects of brick fabrication as the construction of kilns

and critical temperatures needed in producing bricks of desired quality.

4
Table 1

Mineral Composition of Masonry Materials

Masonry

Material Porosity (%) Typical Mineral Composition Ref.

Granite 0.5-1.

5

Feldspars, quartz, hornblende,

mica

[14]

Gabbro 0.1-0.

2

Hornblende, feldspar, plagioclase,

mica

Basalt 0. 1-1.0 Hornblende, feldspars

Porphyry 0.5-1.

5

Feldspar, hornblende

Limestone 5.0-20.0 Calcite, clay minerals

Sandstone 5.0-25.0 Sand, quartz, feldspar, calcite

Dolomite 1. 0-5.0 Calcium carbonate, magnesium

carbonate

Travertine 5.0-20.0 Calcite, various other metallic

compounds

Shale 10.0-30.0 Mica, quartz, calcite, clay,

metalic oxides

Slate 0.1-0.

5

Mica, quartz, calcite

Marble 0. 5-2.0 Calcite, mica, quartz

Quartzite 0.1-0.

5

Quartz, mica, sand

Gneiss 0.5-1.

5

Feldspar, quartz, hornblende

Clay Brick 23.0-40.0 Clay or shale (largely aluminum

silicate)

[9]

Clay Tile 23.0-40.0 Clay or shale, silica, metallic

oxides

Terra Cotta 23.0-40.0 Clay, silica, metallic oxides

Hardened Portland

Cement 5.0-40.0 Hydrates of calcium silicate,

calcium aluminates, calcium

aluminof errite, calcium oxide,

calcium sulphates, water

5
Cinder Block 5.0-20.0 Hardened hydrated portland cement,

quartz, cinders

Concrete Block 1.0-10.0 Hardened portland cement, quartz

gravel

Lime Mortar 1.0-10.0 Calcium oxide, calcium hydroxide, [19]

calcium carbonate, quartz

Portland

Mortar

Cement

1.0-10.0 Calcium silicate hydrate, calcium

hydroxide, sand, water (occasionally

lime

)

Note: Porosities for cement products indicate only orders of magnitude.

6
2 . 2 MORTARS

Among others, Taylor [19], Brunauer and Copeland [8, 19] have dealt

exhaustively with the subject of portland cement and the various hydrates

produced when it combines with water. Portland cement and its various

modifications grew out of the discovery patented by John Aspdin [8], an

English bricklayer, in 1824. This material has largely replaced most of

the earlier cementitious materials used in mortars.

Earlier mortars based on lime (calcium oxide) have been used for more

than 5000 years, since they were used by the Egyptians in the construction

of the pyramids. Much later the Romans combined lime paste with volcanic

ash to produce mortar which they called hydraulic lime, since this mortar

when mixed with water give insoluble cementitious products. Mortars based

on lime were still in common use during the planning and early phases

of the construction of the Gulf Coast forts [7]. Combinations of slaked

lime and portland cement are still employed for some masonry purposes.

The chemical natures of constituents of hardened mortars and other masonry

materials which include the elements of hardened mortars are indicated

in table 1. Porosities given for these materials indicate only orders

of magnitude since in Portland cement mortars porosity varies widely with

the water-cement ratio and the age of the mix. Possible mechanisms of

interactions between these mortars and herbicides will be discussed in

the following chapter.

3. DEGRADATION OF MASONRY MATERIALS

The rate of attack of masonry materials of chemical agents depends on a

number of factors, among them the chemistry of the masonry material, the

7
chemistry of the attacking substance and the amount of surface exposed

to attack. With mortar this surface is determined to a large extent by

its porosity. Other factors being equal, the rate of attack varies directly

with porosity. For the masonry materials listed in table 1, the decreasing

order of resistance to chemical attack is roughly as follows: quartz,

feldspar, calcite, calcium silicate hydrate, calcium hydroxide. The principal

ingredients of mortar are sand, hydrated calcium silicates and calcium

hydroxide; because of its composition and its high porosity, mortar is

more vulnerable to chemical attack than most masonry units. Portland cement

mortar and its predecessor, lime mortar, are so stable at ambient temperatures

and in dry environments that samples of lime mortar known to be 4500 years

old are still in good condition [8]. Their solubility in water is low

but not negligible, and attack by strong alkali is a potential danger.

Ammonium compounds tend to be damaging to hardened port land cement and

lime products, as are materials which produce the sulfate ion. All acids

have a deleterious effect on concrete and mortar, the effect varying roughly

with the strength of the acid [9, 10, 11]. Fats and oils which may be

saponified in the presence of calcium hydroxide or which may undergo hydrolysis

or oxidation to produce acids will attack portland cement and lime mortars.

The presence of carbon dioxide or sulfur dioxide in substantially higher

quantities than are normal in air accelerates the decomposition of portland

cement and lime mortars [9, 10]. Kleinlogel [10] presents an extensive

list of substances and the effects of these substances on masonry materials.

The Structural Clay Products Institute, which has been succeeded by the

Brick Institute of America, published a Technical Note on the effects of

various materials on mortars which is less extensive than the book by

Kleinlogel but is more recent in its date of publication [9]. Masonry

8
units which contain large amounts of calcite, e.g., limestones, marble and

a number of sandstones, are subject to acid attack. Those containing largely

quartz or other forms of silica, e.g., granite, porphyry, and gneiss are

considerably less so. Fired clay brick is particularly resistant to attack

by chemicals. Unfired clay adobe and bricks are not usually subject to

chemical attack but over long periods of time are eroded by running water.

9
4. HERBICIDES

Kearney, Kaufman, et al. [12] have separated herbicides into eleven

categories for purposes of studying their degradative reactions. A list

of these categories with the basic structure for each follows.

a. Phenoxy alkanoic Acids

c. Substituted Ureas

10
d. Methyl Carbamates and Phenyl Carbamates

CHo — N — COOR

3

l H

e. Chlorinated Aliphatic Acida

CX

3

( CXY ) COOR where X = H,C1; Y = Cl.H; and n = 0, 1, 2, ...

f. Chloroacetamides

h. Amitrole2

2 The use of commercial designations is a convenience in identifying

particular chemicals; it does not imply endorsement of the material by

the National Bureau of Standards.

11
i Trifluralin and Related Compounds

j. Dlquat and Paraquat

Diquat

where = CFp SC^CH^, etc.

k. Benzoic Acid Herbicides

X

where R = COOH, CN, CONH, CSNH2> etc.

and X = Cl, OH, OCH

3

, NH2 , etc.

The Farm Chemicals Handbook [20] gives pertinent data on most commercial

members of all eleven of these categories. Given the commercial name, this

volume will present the chemical name and formula and other commercial

names, its chemical action and properties, toxicity, applications, formulations, combinations, limitations, etc.

12
5. DISCUSSION OF HERBICIDAL EFFECTS ON MASONRY

It must be understood that the formulas illustrated represent families of

compounds rather than specific materials. Also important is the fact that

many commercial herbicides are mixtures of members of two or more of these

categories. The commercial preparation Tordon (R) 101R is, for example,

a mixture of the triisopropanol amine salt of 2, 4 - dichlorophenoxy acetic

acid (category a) and the triisopropanol amine salt of 3, 5, 6 -

trichloropicolinic acid. Since the amine salts of these two carboxylic

acids are weakly alkaline in aqueous solution (pH more than 7), it is

unlikely that damage would occur to masonry if this material were used

to control vegetation but care must be taken to consider the degradation

products of these materials. Consider, for example, the oxidative decomposition of 2, 4 - dichlorophenoxy acetic acid under the influence of certain

microbes or through certain other methods of oxidaton.

_^

C0

2 + H2 0 + Cl".

As indicated, the phenoxyacetic acid (I) is converted to the hydroxy-phenoxy

acetic acid (II) which is further oxidized dichloro catechol (III) the 6, g'

dichloro-muconic acid (IV) and, finally, carbon dioxide, chloride ion and

water.

13
Although with Tordon (R) 101R the amine may completely neutralize the acetic

acid group of the original molecule, considerable acidity may develop as

the ring portion of the molecules changes gradually to form muconic acid.

When total decomposition occurs, carbon dioxide and chloride ion are produced

both of which are damaging to cementitious materials when the quantity

is sufficiently large and water is present [10, 16]. The present level

of understanding does not include the rates of the reactions outlined above.

It is therefore, impossible to determine the maximum concentration of

corrosive elements at any given time after masonry has been exposed to

this herbicide. A generalization may be from Kearney's report [12] and

from classical organic chemistry that oxidation of herbicides, as of organic

substances in general, generally produces materials of greater acidity than

the original material. Hydrolyses catalyzed by enzymes also increase acidity.

Fats or oils are saponified, through a metathetical reaction in which the

acid component of the fat or oil attacks the calcium of the cementitious

material. One may thus conclude, in the absence of specific information

to the contrary, that any acid that is water soluble, even though only

slightly so, or any material which may oxidize or hydrolyze to produce

acid, must be regarded as a possible threat to the masonry. One must

consider also the possible corrosive effect of either acid or alkaline

solutions of herbicides on any metallic substance intimately associated

with the masonry.

6. LITERATURE SURVEY AND PRELIMINARY CRITERIA FOR EVALUATING HERBICIDES

6 . 1 LITERATURE SURVEY OF EFFECTS OF HERBICIDES ON MASONRY

An intense computer search through all pertinent data bases (see table

2) revealed two papers by Russian investigator, S.A. Fairushina. Perusal

14
of these papers disclosed that the first dealt with efforts to control

the spiny caper, a plant with a very complex root system that is quite

destructive of mortar joints. A great many herbicides that readily destroyed

the foliage of this plant had little effect on the root system, thus producing

little permanent benefit, since it was the root system that damaged the

masonry. The second paper had to do with the control of certain flowering

plants (Phonerogamae Anthophta) which were destroying the clay brick and

plaster brick roofs of architectural monuments in Middle Asia. Both papers

dealt with the efficacy of the herbicides; neither mentioned the effect

of herbicide on the deteriorating masonry. In both cases, the damage being

done by the herb would have made very difficult, if not impossible, any

quantitative study of damage done specifically by the herbicide. The only

work known to have been done on the effects of herbicides on masonry was

accomplished at the Mississippi Test Facility of the National Park Service

at Bay St. Louis, Mississippi by Fenn, et al. [13], Fenn and his co-workers

soaked pieces of brick and mortar taken from a deteriorated section of

Fort Pickens, Louisiana for one week in 50% aqueous solutions of the

isopropylamine salt of N- (phosphonomethyl) glycine (Roundup) and in a

50% aqueous solution of a mixture of 10.2% 4-amino-3, 5, 6-trichloropicolinic

acid (trisopropanol amine salt) and 39.6% 2.4-dichlorophenoxy acetic acid

(trisopropanol amine salt). This mixture is marketed as Tordon R. The

soaked pieces of brick and mortar were dried, then compared with non-soaked

samples for resistance to cracking, crumbling, and abrasion. After this

experiment, the solutions used for soaking were tested for herbicidal

activity. Results are shown in table 3. Fenn and his associates found

no change in the masonry samples as a result of the soaking and no change

in the herbicidal activity of Roundup due to contact with the masonry.

15
Table 2 . Data Banks

1. Engineering Index

2. Biological Abstracts

3. Chemical Abstracts Chem. Con. 76-86

4. Chemical Abstracts Chem. 707 72-75

Table 3. Germination of brome and radish seeds in

water, herbicide solution and herbicide

leacheate from brick and mortar.

Treatment Seed Germination

Brome Radish

Total .Germinated (%) Total Germinated (%)

Water 30 21 70 30 22 77

Roundup (1:9 solution) 20 0 0 30 0 0

Tordon 101

(1:9 solution) 20 14 70 20 10 50

Roundup (brick leacheate) 60 0 0 60 0 0

Tordon 101

(brick leacheate) 60 1 1.7 60 45 75

16
However they found an appreciable diminution in the activity of Tordon.

Since the Roundup did not change in activity discernibly in one week of

soaking, it is reasonable to assume that it did not decompose, producing

acid decomposition products which might have attacked the masonry. Tordon,

however, did show considerable diminution of herbicidal strength indicating

that the phenoxy-acetic acid may have decomposed in the manner discussed

in Section 5. If so, it is quite possible that the decomposition products

may have caused changes in the masonry samples that were too slight to

be detected by the procedures used. The findings of Fenn et al. are valuable,

but a week is not a sufficient period for such a test and their technique

for detecting changes in the masonry was unlikely to have been sufficiently

sensitive

.

6.2 CRITERIA FOR EVALUATING HERBICIDES

The following are proposed as basic criteria when herbicides must be selected

for use on historic structure.

1. The herbicide, when properly applied, should destroy the objectionable

plant life.

2. It should not be destructive to masonry or other building components.

3. It should not be destructive of the ecology.

4. It should create a hostile environment for reinfestation by the undesirable

vegetation.

5. It should be such that its application would not constitute an extreme

hazard to personnel.

6. Its cost should not be exorbitant.

17
Criteria 1, 2, 3, 4, and 5 concern matters related to plant life and

biological effects. Criterion 2, which relates to the subject of this

report may be expanded as follows:

a. The herbicide and its decomposition products should not cause

defacement or discoloration of the masonry or mortar.

b. It should not reduce the tensile or compressive strength or the

impact resistance of the masonry, or in any other way, affect its

integrity adversely.

Methods are known for testing for compliance with both divisions of criterion

number 4 and for testing for compliance with all of the six criteria listed

above

.

6.3 OUTLINE OF EXPERIMENTAL PROGRAM FOR STUDYING THE EFFECTS OF HERBICIDES

ON MASONRY

For the purpose of selecting desirable herbicides to be used in controlling

obnoxious vegetation in the vicinity of masonry which is of historic or

artistic importance, a screening program is required. An approach to such

a program is suggested in the following paragraph.

Small samples of mortar, concrete, adobe or other masonry material whose

stability to herbicides is of interest would be prepared and aged for a

reasonable period of time. Three or more samples of each form of masonry

to be tested would be exposed to candidate herbicides under conditions

which duplicate as nearly as possible the conditions ordinarily observed

in the field use of herbicides. Similar samples would be tested under

more severe conditions. Additional samples of masonry would be prepared,

aged in the same manner but protected from contact with any herbicides.

18
Microscopic examinations would be made of all samples at regular intervals.

After each examination, the exposure to herbicides would be repeated until

clearly detectable changes in the masonry samples were observed or until

it was determined that no significant change in the masonry sample was

occurring. If appreciable changes in any sample occurred early in the

course of these experiments, this phenomenon would be studied more thoroughly.

Color changes, reflectance, pH measurements or other sensitive tests, would

be carried out in efforts to monitor very slight changes very early. The

nature of the finding would determine the type of report that would be

written to cover this work. Ths approach is infinitely flexible and would

be easily modified if conditions or exigencies required such alteration.

7. CONCLUSIONS AND RECOMMENDATIONS

The literature contains very little concerning the effects of herbicides

on masonry. The National Park Service has made a beginning in this area.

Efforts to control undesirable flora could involve continual use of large

amounts of chemicals of various natures. The effects of these chemicals

upon masonry must be studied in the absence of the vegetation that they

are produced to control if variation in the masonry is to be concomitant.

Under actual working conditions, it would be impossible to attribute a

given destructive effect specifically to the herb or to the herbicide if

both were present. Enough is known about the chemistry of herbicides and

their decomposition products to predict that they may have similar effects

on the elements of masonry as those demonstrated by related chemicals

used for other purposes. In the decomposition reactions, the absence of

kinetic data makes impossible the computation of the concentration of

decomposition products at any given point; therefore, the effects of these

19
decomposition products must be established by practical experiments if these

effects are to be known with certainty. Such experiments would involve

exposing the masonry sample to the herbicide in the manner that it would

be exposed in actual use for a substantial period (see 6.3). These exposed

samples along with controls would then be examined microscopically or by

other sensitive techniques which could detect very small changes. From such

small changes one may predict with some accuracy, changes which would take

place over years, decades or perhaps centuries. This general approach would

satisfy the test needs concerning criterion 2 in Chapter 6. Only herbicides

meeting the minimum requirements of the other 5 criteria need be tested.

8. ACKNOWLEDGEMENTS

This work has been supported by the National Park Service. The author

appreciates the assistance provided by Mr. John Garner, Historical Architect,

of the Southeast Region of the National Park Service.

The author gratefully acknowledges also the advice and assistance of all

his colleagues in the Materials and Composites Section of the National

Bureau of Standards, especially that of Drs. James R. Clifton, Gerald A. Sleater

and Geoffrey Frohnsdorff. The enthusiastic and extremely competent assistance

of Miss Elsie Cerutti of the NBS Library Staff was highly significant in

the preparation of this work. Her assistance is greatly appreciated.

20
References

1. Richardson, B.A., Control of Biological Growths, Stone Industries,

Volume 8, No. 2, March-April, 1975.

2. Fairushina, S.A., Capparis Spinosa L.A., A Destructive Agent of

Architectural Monuments in Uzbekistan, Uzbekistii Biologicheskii

,

No. 5, 1974 (Russ).

3. Fairushina, S.A., The Application of Herbicides in the Control

of Destructive Plants on Architectural Monuments, Dokl. Adad, Nauk,

UZSSR, 2, 60-61, 1975 (Russ).

4. Pochon, T. and Tchon, Y. , Role of Microorganisms in the Alteration

of Paris Monuments, C. Prud. Acad., S.C., 223 p . 695, 1946.

5. Hyvert, Giselle, the Bas-reliefs of Boro Budur, Materials and Factors

Responsible for Degradation Program of Conservation, Studies in

Conservation, Vol. 18, pp. 135-155.

6. Plummer, Harry C., Brick and Tile Engineering, Structural Clay

Products Institute, 1750 Old Meadow Road, McClean, VA, 1964, pp.2-3.

7. Garner, John, Private Communication

8. Brunauer, S. and Copeland, L.E., The Chemistry of Concrete,

Scientific American, Vol. 20, No. 4, pp . 81-92, April, 1964.

9. Chemical Resistant Clay, Masonry, Technical Note on Brick and Tile

Construction, Structural Clay Products Institute, 1750 Old Meadow

Road, McClean, VA 22101, 32 August 1968.

10.

Kleinlogel, A., Influences on Concrete (Translated from the German

"Einflusse auf Beton by J.S. Margeuroth) Frederick Ungar Publishing

Co.

,

New York, 1941.

21
11. Soderstrum, William K. , Cleaning Clay Masonry, A Status Report on

the Investigation of Effective Methods of Removing Various Stains

from Clay, Masonry, Structural Clay Products Research Foundation,

Geneva, IL, 1964.

12. Kearney, P.C. and Kaufman, D.D., Degradation of Herbicides, Marcel

Dekker, Inc., New York, 1969, pp . IX-XI

.

13. Fenn, D., Anderson, W. , Burge R. and Rickett, R. Private Communication

14. Winkler, Erhard, Stone: Properties, Durability in Man's Environment,

Springer Verlag, New York, (1973), pp. 1-29.

15. Ibid, p. 93.

16. Ibid, pp. 90-91.

17. McKee, Harley J., Masonry: Stone, Brick, Mortar and Plaster,

National Trust for Historic Preservation and Columbia University,

1973, pp 41-59.

18. Norton, J. H. , Elements of Ceramics, Addison-Wesley Press, Inc.,

Cambridge, Massachusetts 1952.

19. Taylor, H.F.W., The Chemistry of Cements, Vols. 1 & 2, Academic

Press, London and New York, 1964 pp . 168-229, 268-370.

20. Farm Chemicals Handbook 1977, Meister Publishing Company, 37841

Euclid Avenue, Willoughby, Ohio 44094 216-942-2000.

22
MBS-l lA (REV. 7-73)

U.S. DEPT. OF COMM. BI3LI0GRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 78-1449

2. Gov’t Accession

No.

3. Recipient’s Accession No.

4. TITLE AND SUBTITLE

The Effects of Herbicides on Masonry

5. Publication Date May 1978

6. Performing Organization Code

7. AUTHOR(S)

James Feam

8 . Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No.

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

The National Park Service

U.S. Department of the Interior

Washington, D.C.

13. Type of Report & Period Covered

14. Sponsoring Agency Code

IS. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less (actual summary of most significant in formation. If document includes a significant

bibliography or literature survey, mention it here.) In preserving historic structures, the control of obnoxious vegetation is a serious

problem. To deal with this problem, a number of organic herbicides have been

developed by industry. The efficacy of herbicides in the control of plant life has

been studied to a great degree; but heretofore, very little has been reported about

the possible effects of these chemical plant killers on the materials they are designed to protect. In this work, an exhaustive survey of pertinent literature has

been undertaken. Obtaining very little specific information from literature, a correlation has been drawn between the effects of masonry of materials similar in

chemistry to herbicides and the effects that would be expected from the herbicides

themselves. Methods for checking the validity of conclusions are suggested.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons)

Herbicide*, masonry; historic structures*, degradation', acidic, alkaline

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