\\,

USE OF POLYMERS IN HIGHWAY CONCRETE

MECHANICAL PROPERTIES OF POLYMER CONCRETE:

A LITERATURE REVIEW

By

H. C. Mehta

·. This work has been carried out as part of the project "Use of Polymers in Highway Concrete" sponsored by National Coun~il of Highway Re­search program.

DEPARTMENT OF CIVIL ENGINEERING

Fritz Engineering Laboratory Lehigh University

Bethlehem, Pennsylvania

March 1973

Fritz Engineering Laboratory Report No. 390.2

TABLE OF CONTENTS

ABSTRACT

1 o INTRODUCTION

2 o REVIEW OF TESTS AND RESULTS

2ol Polymer Impregnated Concrete (PIC) 2o2 Fiber Reinforced Polymer Impregnated Concrete

3o DISCUSSION

4 o CONCLUSIONS AND RECOMMENDATIONS

5o ACKNOWLEDGMENTS ,;·.

6 o TABLES AND FIGURES

7 o REFERENCES

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1

3

3

6

7

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ABSTRACT

Extensive studies conducted by Brookhaven National Laboratory

(BNL) and the Bureau of Reclamation (USER), and confirmed by studies

at Lehigh and other institutions, demonstrate remarkable 3 to 4-fold

improvements in the physical and mechanical properties of concrete by

impregnation with a low viscosity liquid monomer such as methyl metha­

crylate followed by in situ polymerization. Little work so far done

in impregnating fiber reinforced concrete with polymer shows the

tremendous potential of the new material in much better strength,

flexibility, toughness, impermeability and corrosion resistant properties.

However, the general opinion of researchers in this field is that at

present the ultimate strength of polymer impregnated materials has not

been reached due to obvious lack of co.mplete understanding of the

interrelations between concrete porosity and polymers.

In this report an attempt has been made to review concisely

the mechanical properties of polymer Lmpregnated materials from the

literature available to date.

390.2 -1

1. INTRODUCTION

A wide range of concrete polymer composites are under investi-

gation at present. Concrete has been used in one form or another since

Roman times. However, some of the major deficiencies of the concrete .

presently used are lack of sealing qualities, strength and wearing

ability and susceptibility to cracking and spalling. To overcome these

deficiencies, the old technology of concrete is combined with the new

technology of polymers to produce an unique material. Extensive studies·

conducted by the Brookhaven National Laboratory (BNL) and the United

States Bureau of Reclamation (USBR), and confirmed by studies at Lehigh

and other institutions all over the world, demonstrate remarkable 3 to

4-fold improvements in the physical and mechanical properties of concrete

by impregnation with a low viscosity iiquid monomer followed by in situ

polymerization.

2. REVIEW OF TESTS AND RESULTS

2.1 Polymer Impregnated Concrete

Much information on the structural and durability properties

of PIC has been accumulated over the past four years in the United

St t (1,2,3,4) a es. Typical reproducible improvements are summarized in

Table I(S) and comparison of strength due to different polymers in

Table II(3) and strength and cost benefit index with other types of

·concrete are shown in Table III~ 7 ) Much of the information presented

has appeared in BNL annual reports and in research articles which have

been appearing more and more fr~quently in scientific and engineering

( 1 2 3 4) journals. ' ' '

---------f"'r.!!

390.2 -2

In general all the composite systems showed significant

improvement in strength and durability. The Methyl Methacrylate (MMA)

and Methyl Methacrylate-Trimethylolpropane Trimethacrylate (MMA-TMPTMA)

impregnated concretes have given the best results (Table II, Figs. 5, 6,

7). Also the improvement in strength appears to be a function of polymer

loading. Improvement in durability appears to be mainly a function of

the polymer loading and the degree of success in sealing the surface

of the concrete. A number of preparation variables were investigated

including concrete composition, drying temperature, curing time, and

the age of the test. The age of concrete at impregnation or its

initial strength does not appear to sig~ificantly affect the final

( 1 2 3) strength. ' '

A series of ten different concrete mixes was produced to

investigate the effect of concrete mix design on the compressive

strength and polymer loading of PIC~4) The controls averaged between

4,220 and 7,280 psi in compression while the PIC specimens exhibited

essentially the same strength, 21 ksi ± 1.8 ksi. This work is currently

being expanded to include a wide range of mix variables to optimize

produce quality and process technology.

The impregnation of high pressure steam cured concrete with

MMA has produced PIC specimens with the highest compressive strengths

of up to 27,000 psi. Similar improvements in tensile strength and

modulus of elasticity are obtained •

-~ .. ~....-~--------·---.,-----~ . ··--·--·- --·-----------·--·---~-~---·------- __ ....\...._ ___ . - .. ,.,..........,

390.2 -3

2.2 Fiber Reinforced Polymer Impregnated Concrete

Little research has been done in this field. The combination

of two structural systems PIC and wire or fiber reinforced concrete

result in the most desirable material. Both materials tend to compensate

for the disadvantages when mixed together. Some interesting results

have recently been published on PIC fiber reinforced mortars. These

results show that for a mortar with 2% by volumn of 3/4" by 0.015"

diameter steel fibers, an increase by about 5 times ·in maximum load

and deflection for the steel fiber reinforced mortar over the plain

mortar. When polymer is added to the fiber reinforcement, another factor

of 5 results, and the failure mode chan~es. Now the steel fibers them-

selves break, so that the presence of the polymer permits the full

utilization of the strength of the steel. Failure is no longer sudden,

as in PIC mortar; the material behaves in a plastic manner, and can

absorb 50 times as much energy at failure as the polymer filled mortar

(F . 8) R k . N h . . 1 . ( 14' 15) 1g. • ecent war 1n orway s ows s1m1 ar 1mprovements.

3. DISCUSSION

1. Perhaps the most dramatic demonstration that a fundamental change-

in the nature of concrete after polymer impregnation takes place is

to observe a PIC specimen fail in compression .(Fig. 1)~ 1 ' 2 ' 3 , 12 ) The

normal concrete on failure exhibits a few cracks but essentially re-.

mains in one piece. However, PIC completely shatters on fracture.

What is most significant about the fracture is that the cracks pass

through, not around the large aggregates (Fig. 2). This suggests that

-- --- --·--- -------·----------------------------. --------------- --~

390.2 -4

the role of the polymer must be, at least in part, to significantly

strengthen the bond between mortar and aggregate.

2. Further evidence of the change in the nature of PIC is the stress

strain relationship (Figs. 3, 4)~lS) The normal concrete shows typical

non-linear stress-strain behavior from nearly the start of loading, at

fracture, the stress-strain curve is nearly horizontal. The PIC sample

behaves much differently. The stress-strain curve is linear until 75%

of the fracture load and at fracture there is relatively little devia-

tion from linearity. PIC thus behaves essentially elastically which will

have an Lmportant bearing on design criteria. The linearity of the stress

strain curve supports the suggestion tha~ part of the role of polymer is

to Lmprove mortar-aggregate bond.

3. Probably the most critical single factor affecting the compressive

strength of PIC is the degree that the pores of the concrete are filled

. (11) (F~gs. 5, 6, 7). There is a very strong dependence of strength on

polymer loading for any PIC system, the maximum strength is obtained

with the maxLmum polymer loading. The effects of increasing polymer

content on the stress strain curve are:

(i) to increase the linear portion of the stress-strain curve,

(ii) to increase the strain at failure,

(iii) to increase the strain energy stored by the specimen.

These results confirm observations noted by Auskens and Horn(9) using

specimens in compression and by Flagsman et al(S) for the load deforma-.

tion curve in flexure (Fig. 8).

390.2

4. The greater the initial strength of concrete, the greater the PIC

strength, although the relative increase is greater for weaker con­

cretes~J,ll)

-5

5. The polymer acts as if it were an equivalent volume of cement paste.

The ability of the monomer to penetrate the microstructure of the con­

crete would therefore appear to be vitally important in producing a

composite of minimum porosity. The properties of the polymer in the

micropores could thus control the properties of the concrete polymer.

The effect of the polymer on the microstructure may then account for

the synergism in compressive strength and elastic modulus obtained

through polymer impregnation~ll)

6. The properties of concrete-polymer materials are primarily controlled

by the particular polymer used~ll) However, out of all polymers, MMA

and MMA+lO% TMPTMA produce the highest compressive strengths (Figs. 5, 6, 7).

The origin of all these polymer differences is not apparent. A number

of possible mechanisms may be advanced to explain the role of the

polymer in changing the properties of concrete. The extent of the

changes may be determined by the ability of the polymer:

(i) to act as a continuous, randomly oriented, reinforcing net

work;

(ii) to increase the bond between the aggregate and the cement

paste;

(iii) to repair microcracking in the cement paste;

(iv) to absorb energy during deformation of the composite system;

(v) to penetrate and reinforce the micropores of the cement paste;

(vi) · to bond with the hydrated or unhydrated cement.

--------------·---- ------ ~

390.2 -6

The repair of microcracking at the aggregate-cement interface is taken

to be included in mechanism (ii) above. Auskern has suggested the second

explanation probably forms the dominant mechanism~G,lJ) Flagsman et al

attributed the increase in strength of glass and steel fiber reinforced

mortars to improved filament to matrix bonding due to polymer impregnatio~~)

4. CONCLUSIONS AND RECOMMENDATIONS

The researchers generally agree that the work to date has

indicated that remarkable improvements in the structural and durability

properties of concrete can be obtained by monomer impregnation and in

situ polymerization by either radiation-or thermal catalytic means.

However, it is quite likely that at present the ultimate strength for

PIC has not been reached. One reason for this is that a complete under-

standing of the interrelations between concrete, porosity, and polymer

has not been achieved. Hence, the following recommendations are generally

made for the future program:

1. Investigation should be made to obtain a better understanding of

the major factors controlling the physical and mechanical properties

of concrete-polymer materials. Important parameters include the effect

of variation of concrete composition, aggregate type and size, method

of curing and polymer loading.

2. Experiments should be performed to determine the effects produced

by the addition of additives to monomer prior to impregnation. · Additives

to be tested should include fire retardants, wetting agents, coupling

agents, plasticizers, and thixotropic materials.

390.2 -7

3. Further work should be done.on evaluating polymer concrete (PC) and

polymer cement concrete (PCC) and on the use of both radiation and thermal

catalytic techniques of polymerization. In addition comprehensive strength

data should be obtained on all concrete-polymer systems to yield data on

maximum and minimun strength curves for a given monomer.

4. Fundamental studies on the basic nature of concrete-polymer materials

should be continued to determine areas for further improvement.

5. Investigations should be continued to develop reliable methods for

the quality control of concrete-polymer products.

6. Design code requirements and preliminary process and product designs

should be formulated using data for prototype and full-scale units to

obtain systems for yielding optimum product quality and process tech­

nology at minimum cost.

/

5. ACKNOWLEDGMENTS

This study is part of a research project on "Use of Polymers

in Highway Concrete" which is being conducted at Fritz Laboratory, Depart­

ment of Civil Engineering, Lehigh University. The project is sponsored

by National Council of Highway Research Program. Dr. J. A. Manson is the

principal investigator and Dr. W. F. Chen is co-investigator. Dr. D. A.

VanHorn is Chairman of the department and Dr. L. S. Beedle is Director of

Fritz Engineering Laboratory.

Thanks are due to Dr. W. F. Chen, Dr. J. A. Manson and all other

personnel connected with this project for their help in finding the avail­

able published literature and updating the literature file.

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390.2

TABLE I(5)

CONCRETE POLYMER MATERIALS--S~fi1ARY OF PROPERTIES OF METHYL-METHACRYLATE IMPREGNATED CONCRETE1

PROPERTY CONTROL TREATED

Compressive strength, psi 5,267 20,255

Modulus of elasticity, 106 psi 3.5 6.3

Tensile strength, psi 416 1,627

Modulus of rupture, psi 739 2,637

Flexural modulus of elasticity, 106 psi 4.3 6.2

Abrasion, in. 0.0497 0.0163 (g) 14 4

Cre·ep for 800 psi load after 90 days, 106 in./in. -95* +34

Hardness impact (111'1 hammer) 32.0 ·55.3

DIFFER-ENCE

PERCEN'f3

285

80

291

256

44

-67 -71

Negative creep

73

1Dried concrete specimens containing 4.6 to 6.7 weight percent PMMA

2 =radiation-control (lOO). Difference percent control

*Control creep data are for 30 days in test.

- • ..

390.2

TABLE II (3) · ........ :.._--:, ..... -_ .. ::. ::.. ,_ ._ .... .;-· ......

·-

CONCRETE COMPRESSIVE STRENGTH WITH DIFFERENT POLYMERS

POLYMER WT. LOADING 1 i. COMPRESSIVE STRENGTH 2 PSI . .

RANGE THERMAL CURE RADIATION CURE

MMA 4.2-6. 7 18,200 20,300

Styrene 4.2-6.0 8,800. 14,100

MMA + 10% TMPTMA* 5.5-7.6 19,000 21,600

Acrylonitrile 3.2-6.0 10,750 14,410

Ch1orostyrene 4. 9-6.9 14,400 16,100

*1MPT}~ = Trimethylolpropane trimethacrylate

. 390.2 .... --..;10

I.

1- TABLE I II ( 7) CLASSIFICATION OF CONCRETE-POLYMER MATERIALS

Polymer Loading Compressive Strength Benefit

wt% Density Strength Weight Cost PMMA lbs/fe lbs/in. 2 Ratio Durability Index

1. Conventional Concrete Control 0.0 150 5,000 33 Poor 1.0

2. Surface Coat-ing (SC) Paint or Overlay 0.0 150 5,000 33 Limited 1.1

3. ·coating in Depth (CID) 1.0 150 6,000 40 Good 1.3

.. t' 4. Polymer Cement Concrete (PCC) Premix 35.0 130 7,500 58 Fair 0.4

5. Polymer Im- . pregnated Con- .. crete (PIC)

Standard Aggregate

a. Undried-Dipped 2.0 153 10,000 49 Fair . 1.4 b. Dried-Evac.-

Filled 6.0 159 20,000 126 Very Good 2.0 c. Hi-Silica

Steam Cured 8.0 159 "38,000 240 Very Good 3.0

Light,.;eight Aggregate r

a. Struct. Lt. Wt. Caner. 15.0 130 25,000 193 Very Good 2.5

b. Insul. Lt. Wt. Caner. 65.0 60

i: 5,000 84 Very Good 2.5

6. Polymer Concrete (PC) Cement less 6.0 150 20,000 133 Excellent 4.0

... ·

' 390.2 !::..U~.

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TABLE IV(8) MECHANICAL. PROPERTIES OF FIBER- AND POLYMER-REINFORCED MORTARS(l5)

Ultimate Increase Toughness Compressive Flexural In Strength

Fibers Polymer Strength. Strength (vol%) (wt%) (k~f/ cm2

) (%) (kg-em) (kgf/cm2)

Plain 0 0 12 100 0.06 109

Plain (Hoist-Cured) 0 0 40 330 371

Polymer-Impregnated 0 7.4 61 510 1.05 413

Glass-Fiber-Reinforced 2.0 0 54 450 2. 72 39

Glass-Fiber + Polymer-Reinforced 2.0 10.7 136 1130 3.16 513

Ste~l-Fiber-Reinforced 2.0 0 54 450 2.09 100

Steel-Fiber + Polymer-Reinforced 2.0 9.1 "338 2820 61.50 894

/"

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390.2

Fig. 1 Fracture of Normal Concrete (Left) and Polymer Impregnated Concrete (Right)

-12

390.2

i )

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Fig. 2 A Section Through 3x 6 Inch Cylinder of Polymer Impregna t ed Concrete

J

18

16

14

~12 0 )(

·-10 f/)

a. -C/) (/) w a:: 1-CI)

2

0

' . ·.;

,

P.l. C. P MMA Loading 5.4°/o

E = 5 .. 5 X I 0 6 psi

2000 4000 . .

COMPRESSIVE STRAIN (,uin/in)

•

. Fig. 3 Comparison of Compressive Stress-Strain Relationship for Normal and ~olymer Impregnated Concrete

-14

-·-f/) 0.. 0 0 0 -en en w a:: l­en

20

0

Fig. 4

.; .

· ..

,.

,

CP4AI5E 1/ . 6 I

E1_4=6.58-7.25xl0 I . I

! I I · 6 .

. 5-8

E= 6.49x 10 psi

r.

9-12 Cycles . . 6 Eg-12= 6. 49-6.52 xl 0

6 E5-8 = 6.64-6.72 X I 0

4000

STRAIN (,u.in./in.).

.) : I

. ~

Stress-Strain Relationship for Polj~er Impregnated Concrete After Cycling

-15

20

-(/)

g16 0 0 -:c ..... (!) 12 z w 0:: ..... C/)

w 8 > C/) C/) w 0:: a.. ~ 4 0 u

0

• • -16

,

r 1 I

..

/1 -I I

I

,'--Styrene-Radiation MMA- Radiation 1·

.J r, MMA+5°/o Peroxide

at 167° F. /.

~~~ A -

~:7' "'£ . . . .. ·~~ /,..- "' Styrene-2% Peroxide ,j:Y A ~ at 167° F. . ,, ..,.,. .

·'

~"' ~ ----- ., .. n.::::ae:-::--_...-- , A

-;

'4 6 POLYMER LOADING (wt. 0/o)

II

· Fig. 5 Compressive· Strength as a Function of Polymer Filling

. ;;

..

... :·_.

-17

, ·.,:· .. ~

16 MMA-Radiation -U) oo a. 0 I

N r I 0 0 - I

:r: I

..... 12 0 /,..__ MMA+5°/o Peroxide (!) 0 I at 168° F. z /

~ w a: ..... Styrene Radiation (/)

w 8 -' (/)

:z w Styrene- 2°/o Peroxide t-

4

•

0 2 4 6

POLYMER LOADING (wt 0/o)

Fig. 6 Tensile Strength of Polymer Impregnated. Concrete as a Function of Polymer Filling •

. . ' .. •

,

. 3.2 -·-(/)

0. r() 0 -

•

0 2 4 s· POLYMER LOADING (wt. 0/o}

Fig. 7 Flexural Strength of Polymer Impregnated C6ncrete as a F~nction of Polymer Filling

-18

! .

.:'

. ~. . . ·.

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RELATIVE MAXIMUM LOAD

10 0

80

...

,

60

Polymer Impregnated · VSteel Fiber Reinforced

40

2.0

Mortar

40

; :

Impregnated Mortar

Plain Steel Fiber Reinforced

/

60 8 0 . 100 120

RELATIVE MIDSPAN DEFLECTION

Fig. 8 Load-Deflection Curve for Different Composites

..

-19

... ·.~ r'l

390.2 .-20

7 • REFERENCES

1. Steinberg, M., et al CONCRETE-POLYMER MATERIALS, First Topical Report, BNL 50134 (T-509) and USBR General Report No. 41, December 1968.

2. Steinberg, M., et al CONCRETE-POLYMER MATERIALS, Second Topical Report, USBR REC-OCE-70-1 and BNL 50218 (T-506), December 1969.

3. Dikeou, J. T., et al CONCRETE-POLYMER MATERIALS, Third Topical Report, USBR

. REC-ERC-71-6 and BNL 50275 (T-602), January 1971.

4. Kukacka, L. E. and DePuy, A. W. CONCRETE-POLYMER MATERIALS, Fourth Topical Report, Bur. Reclam. Rep. REC-ERC-72-10, and BNL Rep. BNL 50328, Jan. 1972, Bureau of Reclamation, Denver, and Brookhaven National Laboratory, New York, p. 100, 54 65 tables, 36 ref.

5. Auskern, A. THE STRENGTH OF CONCRETE-POLYMER SYSTEMS, BNL 12890, Sept­ember 1968.

6. Auskern, A. THE COMPRESSIVE STRENGTH OF POLYMER IMPREGNATED LIGHTWEIGHT CONCRETE, BNL 14595, March 1970.

·7. Steinberg, M. CONCRETE-POLYMER COMPOSITE MATERIALS DEVELOPMENT, informal report, Department of Applied Science, February 1972.

8. Flagsman, F., Kahn, D. S., Phillips, J. C. POLYMER IMPREGNATED FIBER-REINFORCED MORTARS, J. Amer. Ceram. Soc., 54 (129-130) 1971.

9. Auskern, A., and Horn, W. SOME PROPERTIES OF POLYMER IMPREGNATED CEMENTS AND CONCRETES, J. Amer. Cerm. Soc., 54 (282-285), 1971.

10. Gebauer, J. and Coughlin, R. W. PREPARATION, PROPERTIES AND CORROSION RESISTANCE OF COMPOSITES OF CEMENT MORTAR AND ORGANIC POLYMERS, Cement and Concrete Research, Vol. 1, pp. 187-210, 1971.

11. Manning, D. G. and Hope, B. B. THE EFFECT OF POROSITY ON THE COMPRESSIVE STRENGTH AND ELASTIC MODULUS OF POLYMER IMPREGNATED CONCRETE, Cement and Concrete Research, Vol. 1, pp. 631-644, 1971 •

... . ·- --·- ·-·--------------~·---.---------~-

390.2 -21

12. Auskern, A. . A REVIEW OF PROPERTIES OF POLYMER IMPREGNATED CONCRETE, report prepared for the proceedings of the conference, New Materials in Concrete Constructions, University of Illinois, Chicago, December 1971.

13. Auskern, A. Informal report, BNL 13493R-3, BNL, Upton, New York, 1970.

14. Mattisson, L. G.

15.

BETONG-POLYMER-FEBERKOMPOSITER, progress report, August 1971, STU-Report 70-68th/U582, Technical University of Lund (in Swedish).

Mattisson, L. G. BETONG-POLYMER-FIBERCOMPOSITER, progress report 70-684/ 4587, Feb. 1972 and 72-201/Ul36, August 1972, Technical University of Lund (in Swedish).