CONCRETE COMPRESSIVE STRENGTH, SHRINKAGE AND

BOND STRENGTH AS AFFECTED BY ADDITION

OF FLY ASH AND TEMPERATURE

By

Tarun R. Naik Ph.D., P.E.

Director, Center for By-Products Utilization

The University of Wisconsin - Milwaukee

P.O. Box 784, Milwaukee, WI 53201

Shiw S. Singh, Ph.D.

Post Doctoral Fellow, Center for By-Products Utilization

The University of Wisconsin - Milwaukee

P.O. Box 784, Milwaukee, WI 53201

Vasanthy Sivasundaram, M.S.

Currently visiting scientist at

Center for By-Products Utilization

The University of Wisconsin - Milwaukee

P.O. Box 784, Milwaukee, WI 53201

Research Engineer, CANMET

Energy, Mines and Resources, Canada

Ottawa, Canada

1

ABSTRACT

The effects of addition of fly ash and temperature on compressive

strength, shrinkage and bond strength of concrete were investigated.

In this study, two different types of concrete with compressive

strengths of 2500 psi and 4500 psi, were designed and tested. The

performance of the concretes were measured at varying amounts of fly

ash inclusion (0 - 30% cement replacement) and three different levels

of test temperature (73, 95 and 120o

F). The results exhibited that

the optimum fly ash ranged from 10 - 20 percent with respect to

compressive strength, shrinkage and ultimate bond stress under the

adverse weather conditions.

INTRODUCTION

Fly ash has been used in concrete to obtain significant economic

and ecological advantages, and to improve the properties of fresh

and hardened concrete. Numerous studies have revealed that the

inclusion of fly ash in concrete causes improvement of several

properties including workability, cohesiveness, ultimate strength

and durability. Besides these properties, a knowledge of drying

shrinkage, expansion, other time-dependent deformations, and bond

strength is of special importance in the design of fly ash concrete

structures.

Drying shrinkage is known to cause cracking in the concrete.

Not much work has been reported on the shrinkage behavior of fly ash

2

concrete under hot and dry weather conditions. Adequate bond between

the reinforcing steel and concrete is necessary in order for the

concrete to be effective in carrying loads. Bond strength appears

to develop due to the friction, adhesion, and mechanical interlock

between the steel and concrete. Cracks in the concrete resulting

from volume change and permeability of the concrete, and corrosion

of the reinforcements are a few of the factors which affect the bond

strength between steel and the concrete. Little research work related

to bond strength of fly ash concrete has been published.

SCOPE OF INVESTIGATION

This research work was undertaken to determine the influence

of inclusion of fly ash and temperature on strength, drying shrinkage,

and bond strength of concrete under simulated hot and dry weather

conditions.

LITERATURE REVIEW

Numerous investigations have revealed that addition of fly ash

in concrete results in lower early age strength and equal or greater

long-term strength [1-6]. In general, high temperatures present

during placing and curing of concrete cause considerable deterioration

in concrete compressive strength [5,7,9,10,12,13]. With respect to

concrete mechanical properties, the optimum quantity of fly ash for

cement replacement is found to vary between 10 - 30% depending upon

properties of fly ash and cement and the curing conditions

3

[2,3,5,6,10,11,14].

Time dependent deformations of concrete has been investigated

by a number of researchers [5,6,10,11,15]. A few of the studies have

shown that inclusion of fly ash in concrete does not cause appreciable

influence on its shrinkage and creep properties [5,11,13]. More

recently researchers have substantiated that fly ash concrete attains

lower values of creep and shrinkage compared to reference concrete

[8,14].

Inadequate compaction of fresh concrete causing voids around

the reinforcing bars, and water pockets forming under reinforcing

bars contribute to reduction in bond strength. Further, the behavior

at the steel-concrete interface is dependent on the aggregate

interlock at the cracks, time dependent phenomena such as creep and

shrinkage, behavior of concrete under multi-axial stress conditions,

and the pullout and dowel actions at the interface [16]. Bond failure

of concrete with large reinforcing bars occurs generally by bursting

of the surrounding concrete; this destructive splitting failures at

low bond stresses occurs for larger bars than smaller ones, since

the splitting capacity of the surrounding concrete governs the

ultimate bond resistance [17]. The slip and bond strength of deformed

bars during fatigue loading is affected the same way as the deformation

of unreinforced concrete under fatigue loading. Rehm and Eligehausen

[18] showed that after 5 x 106 cyclic tensile loadings, the pull out

resistance of a reinforcing bar in concrete decreased by as much as

50%.

4

EXPERIMENTAL PROGRAM

In this investigation, reference portland cement concretes were

designed at two strength levels, 2500 and 4500 psi. Fly ash concretes

were proportioned to have fly ash at cement replacements of 10, 20,

and 30%. Experiments were carried out to determine the compressive

strength, shrinkage and bond strength of specimens as a function of

fly ash addition and temperature. Test temperature and humidity were

maintained to simulate hot weather conditions at three different

temperature levels of 73, 95, and 120o

F. Three series of tests were

conducted. In the first series, tests were designed to study

compressive strength of concretes as a function of fly ash content

and temperature and relative humidity conditions in which the

concretes were made and cured. The second series of tests was planned

to determine drying shrinkage of concrete as a function of fly ash

addition and the above mentioned ambient conditions. The third series

of tests was designed to investigate bond strength characteristics

of concretes containing increasing proportions of fly ash, made and

cured at the three temperature levels.

MATERIALS

ASTM Type I portland cement obtained from the same source was

used in all the series of tests. The physical properties and chemical

analysis of the cement were determined using the appropriate ASTM

standard techniques, and are presented in Table 1. Properties of

5

the fly ash, determined in accordance with ASTM test methods, are

reported in Table 2. The coarse and fine aggregates were air dried

3/4-in. Madison gravel and Ottawa sand. The physical properties of

the aggregates are shown in Table 3.

MIXTURE DESIGN

A trial batch method of mixture design was utilized in this

investigation. Four trial batches were designed and mixed, and

compressive strength specimens were made and tested at various ages.

The trial mixture proportions are given in Table 4. From the results,

mix design curves were plotted as shown in Fig. 1. From the above

curves, two concrete mixture proportions were selected to have 28

day compressive strengths of 2500 (Concrete A) and 4500 psi (Concrete

B). The design mixture proportions are given in Table 6. At each

strength level, fly ash concrete mixtures were proportioned to have

fly ash at cement replacement by weight of 10, 20, and 30%; and the

proportions of the rest of the ingredients were kept constant.

Further, concrete mixtures were made with fly ash at 30% cement

replacement by weight, at both strength levels. The water content

of these mixtures were reduced appropriately in order to obtain

workability equivalent to 1 in. Kelly ball measurement. Additional

concrete mixtures with design

strength of 2500 psi were proportioned in accordance with the technique

developed by Lovewell and Washa [2]. In these mixtures, 30% of cement

was replaced by a larger amount of fly ash. Proportions of the rest

of the ingredients were kept the same as the other concrete A mixes.

6

PREPARATION AND CASTING OF TEST SPECIMENS

All the concrete ingredients were kept in rooms at the three

temperature levels (73, 95 and 120oF) for at least 24 hours prior

to mixing the concretes. All the associated equipment was also kept

at the above three temperatures. The aggregates were mixed dry for

two minutes and then half the required water was added. Wet mixing

was conducted for 45 seconds and then fly ash, cement and the remaining

water was added and mixing was continued for two minutes and 15 seconds.

The resulting mixture was used to cast samples for the test

conditions. The properties of the fresh concretes are given in Table

6.

For the compression tests, cylindrical specimens of 6 x 12 inch

were made in cast iron molds. Cylindrical specimens 6 x 6 inch with

one vertical reinforcement at the center were cast for bond strength

determination. Prism specimens of 2 x 2 x 11 inch were cast for drying

shrinkage measurements.

CURING OF TEST SPECIMENS

All the test samples for the 73oF designation were kept in a

room maintained at about 73oF and 55% relative humidity for the first

three weeks of storage. Beyond this, the room was maintained at 73oF

and 20% relative humidity until all specimens were tested. The

7

specimens for the 95oF designation were kept in a hot room at about

95oF and 70% relative humidity for two weeks after casting and

thereafter at 95oF and 50% relative humidity. For the 120

oF

designation, the specimens were kept in an oven maintained at 120oF

and 55% relative humidity for the first two weeks, and later at about

120oF and 25% relative humidity until testing was completed.

TESTING OF SPECIMENS

Compression tests were performed on 6 x 12 inch cylindrical

specimens in accordance with the ASTM standard technique. Three

specimens were tested for each test condition.

The bond strength tests were performed on the 6 x 6 in. cylindrical

specimens according to the ASTM standards. A machine with a maximum

capacity of 100,000 lbs. was utilized for the pull out test. The

rate of load application was maintained as 0.081 inch per minute.

Two federal dial gages were used to measure displacement of the

reinforcing bars, one for loaded end and the other for unloaded end.

The displacement reading for each end was recorded as a function

of applied load until the specimen failed. Two specimens were tested

for each experimental condition.

The prism specimens (2 x 2 x 11 inch) were tested for length

change by means of a standard length comparator. At the age of 4

days, the specimens were immersed in water for two days and then the

initial length and weight readings for each specimen was recorded.

8

The specimens were then allowed to dry at their casting temperatures

for the remaining period. Changes in length and weight were recorded

at 1,3,5,7,14,28,42 and 56 days. After taking the final reading at

56 days, the specimens were again submerged in the water for two days

and thereafter final changes in length and weight were determined.

RESULTS AND DISCUSSION

The results of this investigation are discussed in three parts.

The first part deals with compressive strength of the concretes,

the second part describe the results of the drying shrinkage of the

concretes, and finally the bond strength of the concretes under

simulated hot and dry weather conditions is discussed.

Compressive strength

The compressive strength data are presented in Table 8 and the

relation between compressive strength and fly ash is shown in Figure

2.

Analysis of the data indicated that compressive strength of the

concrete increased with age for all the test conditions. The

increase in early strength, up to 7 days, did not follow a particular

trend. The results at 28 days revealed that the maximum compressive

strength was attained at fly ash level of 20 percent and temperature

of 120oF for the concrete A, and at fly ash level of 10% and temperature

of 73oF for the concrete B. (Table 8).

9

The maximum 90 day compressive strength was obtained for concrete

A at fly ash content of 10% and at the temperature of 120oF, and for

the concrete B at fly ash content of 10 percent and at the temperature

of 73oF. Therefore, fly ash addition at cement replacement of 10

to 20% by weight appears to be the optimum amount for the hot weather

conditions investigated.

From the results reported above it can be concluded that potential

benefits of fly ash inclusion in concrete A was greater than that

in concrete B for hot weather conditions.

The concretes AEX and B

EX were designed to investigate their

performance at a fly ash level of 30% by replacement of cement and

with a constant workability of 1 inch as measured by the Kelly ball

apparatus in the temperature range of 73 to 120oF.

The strength data up to 28 day exhibited that the performance

of the concrete AEX improved as the temperature was increased from

73 to 120oF, and the same trend was noticed for the concrete B

EX when

temperature was elevated from 73 to 95oF. But, after 28 days, the

strength gain at higher temperatures appeared to be lower. The

long-term strength development of concrete AEX kept at 95 and 120

oF

was found to be equal to or higher than that of the respective portland

cement concretes. Thus the low strength concretes containing 30%

10

fly ash appear to perform well in hot weather conditions, when the

w/c ratio is lowered.

The concrete ALW was proportioned using the recommendation made

by Lovewell and Washa [2], in which 30% by weight of cement was replaced

by a higher amount of fly ash. The analysis of data revealed that

the strength of concrete ALW substantially improved with increasing

temperature at all the tested ages. Further, at higher temperatures,

concrete ALW achieved better strengths than the portland cement

concretes and the AEX concretes. Hence, the high fly ash content

concretes proportioned by this method appear to perform well in hot

weather conditions.

Shrinkage

The relationships between volume changes or drying shrinkage

and age are shown in Figure 3.

At early ages up to 7 days, all the concretes showed nearly the

same drying shrinkage within the tested levels of temperature (73,

95 and 120oF) and fly ash contents (0, 10, 20 and 30 percent cement

replacement).

A study of the curves revealed that the magnitude of shrinkage

decreased with increasing fly ash up to 20 percent, especially at

higher temperatures (95 and 120oF), and ages beyond 50 days and then

11

increased with increasing fly ash (Figure 3). At 73oF and 95

oF, the

concrete containing 20% fly ash and the reference concrete showed

the same results (Figure 3). However, at 120oF, the fly ash concrete

showed consistently higher drying shrinkage as compared with the

central concrete.

Bond Stress

The ultimate bond strength data are presented in Table 8. The

relationships between bond stress and slip are presented in Figures

4 through 9. Relation between bond stress and percent fly ash

inclusion is depicted in Figure 10. Relation between bond stress

at slip of 60 x 10-4 inch at loaded end is shown in Figure 11.

The general trend revealed that the ultimate bond stress

increased with inclusion of fly ash up to a certain limit beyond which

it decreased (Figure 10). The amount of fly ash for the maximum

ultimate bond increased with temperature above 95oF. At 73 and 95

oF,

the 28-day maximum ultimate bond stress was observed at 10% fly ash,

whereas at 120oF, fly ash corresponding to the maximum ultimate stress

was 20%.

The variation of bond stress at a slip of 60 x 10-4 inch as a

function of fly ash followed the same trend as indicated by the ultimate

bond stress (Figures 10 and 11).

CONCLUSIONS

12

The following conclusions were made based on the data observed

in the present investigation.

1.The results showed that the inclusion of fly ash was more effective

in concrete A than in concrete B under hot and dry weather

conditions. The optimum fly ash replacement for cement with

respect to compressive strength varied between 10 to 20 percent

depending upon test temperatures and types of concrete tested.

2.At 30% cement replacement, compressive strength of concrete designed

for a constant workability performed much better than the

concretes designed with a constant amount of water.

3.The concrete proportioned as per recommendation given by Lovewell

and Washa [2] showed increase in strength with increasing

temperatures.

4.At early ages, up to 10 days, both the fly ash concretes and the

reference concretes showed similar shrinkage.

5.In most cases the magnitude of drying shrinkage decreased with

an increase in addition of fly ash up to 20%, particularly

at higher temperatures and later ages.

6.At lower temperatures and later ages, the concrete containing fly

ash showed slightly lower shrinkage as compared with the

13

reference concrete. At high temperature, the shrinkage of the

fly ash concrete was significantly greater than that obtained

for the reference concrete.

7.In general, the ultimate bond stress increased with fly ash

inclusions up to a certain limit and then decreased

substantially.

8.With respect to the ultimate bond strength, the optimum quantity

of fly ash increased with increasing temperature. The optimum

fly ash content as cement replacement was observed in the range

of 10 to 20 percent.

9.The optimum fly ash replacement for cement with respect to

compressive strength, drying shrinkage and bond strength was

observed in the range of 10 to 20% within the experimental range.

REFERENCES 1.R.E. Davis, R.W. Carlson, J.W. Kelly and H.E. Davis, "Properties

of Cements and Concrete Containing Flyash", ACI Journal, May-June 1937, Proc. V. 33, pp. 577-612.

2.Lovewell, C.E., and Washa, G.W., "Proportioning Concrete Mixtures

using Flyash", ACI Journal, June 1958, Proc. V. 54, pp. 1093-1101.

3. Berry, E.E., and Malhotra, V.M., "Fly Ash for Use in Concrete - A Critical Review", ACI Journal, Proceedings V. 77, Mo #2, March - April, 1980, pp. 59-73. 4. Lohtia, R.P., Nautiyal, B.D., and Jain, O.P., "Creep of Fly Ash Concrete", ACI Journal, Proceedings V. 73, No. 8, Aug., 1976, pp. 469-472. 5.Berry, E.E., and Malhotra, V.M., "Fly Ash in Concrete",

14

Supplementary Cementing Materials for Concrete, V.K. Malhotra, Ed., Canadian Government Publishing Centre, Ottawa, Canada,

1987. 6.Lane, R.O., and Best, J.F., "Properties and Use of Fly Ash in Portland

Cement", Concrete International, July, 1982, pp. 81-92. 7. Mittelacher, M., "Effect of Hot Weather Conditions on the Strength

Performance of Set-Retarded Field Concrete", Temperature Effects on Concrete, T.R. Naik, Ed., STP 858, ASTM, Philadelphia, 1985, pp. 88-106.

8.Ghosh, R.S. and Tikalsky, J., "Creep of Fly Ash Concrete", ACI Journal, Proceedings V. 78, No. 5, September - October, 1981.

9.Swamy, R.N., and Stavrides, H., "Some Properties of High Workability

Steel Fibre Concretes", Proceedings, RILEM Symposium and Fibre Reinforced Cement and Concrete, The Construction Press, Lancaster, London, 1975, pp. 197-208.

10.Dalal, R.P., and Naik, T.R., "Effects of Fly Ash and Temperature

on Properties of Concrete", Unpublished M.S. Thesis, University of Wisconsin - Madison, 1964.

11.Ravindrarajah, R.S. and Tam, C.T., "Properties of Concrete

Containing Low-Calcium Fly Ash Under Hot and Humid Climate", In Fly Ash Silica Fume, Slag and Natural Pozzolan in Concrete, V.K. Malhotra, Ed., Proceedings, Third International Congress, Trondheim, Norway, ACI SO-114, ACI, Detroit, 1989, pp. 139-199.

12.Al-Ani, S.H., and Al-Zaiwary, A.K., "The Effects of Curing Period

and Curing Delay on Concrete in Hot Weather", Materials and Structures, Vol. 22, No. 123, May 1988, pp. 205-212.

13.Cebeci, O.Q., "Strength of Concrete in Warm and Dry Environment",

Materials and Structures, RILEM, V. 20, No. 118, July, 1987, pp. 270-272.

14. Swamy, R.N., and Mahmud, H.B., "Shrinkage and Creep Behavior of High Fly Ash Content Concrete", In Fly Ash Silica Fume, Slag and Natural Pozzolan in Concrete, V.K. Malhotra, Ed., Proceedings, Third International Congress, Trondheim, Norway, ACI SP-114, ACI, Detroit, 1989, pp. 444-475. 15. Hansen, W. and Almudaiheem, J.A., "Ultimate Drying Shrinkage

of Concrete - Influence of Major Parameters", ACI Material Journals, May-June, 1987, pp. 217-223. 16.Mirza, S.M., and Houde, J., "Study of Bond Stress - Slip

Relationships in Reinforced Concrete", ACI Journal, V. 76, No. 1, January 1979, pp. 19-46.

17.Morita, S. and Kaku, T., "Splitting Bond Failures of Large Deformed

Reinforcing Bars", ACI Journal V. 76, No. 1, January, 1979, pp. 93-110.

15

18.Rehm, G. and Eligehausen, R., "Bond of Ribbed Bars Under High

Cycle", ACI Journal, Proceeding, V. 79, No. 2, 1979, pp. 97-309. 1989-11

16

Table 1 - Physical Properties and Chemical Composition of Cement ┌─────────────────────────────┬─────────────────────────┐ │Physical tests │ │ │ │ │ │Blaine fineness, cm

2/gm │ 3345 │

│ │ │ │Normal Consistency, % │ 24.5 │ │ │ │ │Setting time, hrs. │ │ │ - Initial │ 3.0 │ │ - Final │ 6.25 │ │ │ │

│Autoclave expansion, % │ 0.094 │ │ │ │ │Tensile strength, psi │ │ │ - 3 day │ 310 │ │ - 7 day │ 400 │ │ - 28 day │ 525 │ │ - 90 day │ 475 │ │ │ │ │Compressive strength, psi │ │ │ - 3 day │ 1900 │ │ - 7 day │ 2955 │ │ - 28 day │ 4965 │ │ - 90 day │ 6365 │ │ │ │ │Chemical composition, % │ │

│ │ │ │Silicon dioxide (SiO2) │ 21.30 │ │ │ │ │Calcium oxide (CaO) │ 63.71 │ │ │ │ │Aluminum oxide (Al2O3) │ 4.79 │ │ │ │ │Ferric oxide (Fe2O3) │ 2.35 │ │ │ │ │Sulphur trioxide (SO3) │ 2.40 │ │ │ │ │Loss on ignition (LOI) │ 0.90 │ │ │ │ │Insoluble residue │ 0.20 │

│ │ │ │Bogue Potential Compounds, % │ │ │ │ │ │C3S │ 55.17 │ │ │ │ │C2S │ 19.47 │ │ │ │ │C3A │ 8.72 │ │ │ │ │C4AF │ 7.15 │ └─────────────────────────────┴─────────────────────────┘

17

Table 2 - Physical Properties and Chemical Composition of Fly Ash ┌────────────────────────────────────┬────────────────────────┐ │Physical tests │ │ │ │ │Fineness │ │ │ - Mean particle diameter, microns │ 6.87 │ │ │ │

│Specific gravity │ 2.47 │ │ │ │ │Autoclave expansion, % │ 0.01 │ │ │ │ │Drying shrinkage of mortar bars │ │ │ │ │ │Mix data │ │ - Portland cement, gm │ 500 │ │ - Fly ash, gm │ 125 │

│ - Graded Ottawa sand, gm │ 1250 │ │ - Water, gm │ 270 │ │ - Flow (consistency), % │ 112.5 │ │ │ │ │Change of drying shrinkage of │ │ │ mortar bars at 28 days, % │ -0.02 │ │ │ │ │Pozzolanic activity index with lime │ │ │ │

│ │Mix data │ │ - Fly ash, gm │ 350 │ │ - Lime, gm │ 175 │ │ - Ottawa sand, gm │ 1575 │ │ - Water, gm │ 350 │ │ - Flow (consistency), % │ 112.5 │ │ │ │Activity Index │ 925 psi

18

│ │ │ │ │Chemical Analysis, % │ │ │ │ │ │Silicon dioxide (SiO2) │ 41.5 │ │ │ │ │Aluminum oxide (Al2O3) │ 27.0 │ │ │ │Ferric oxide (Fe2O3) │ 24.2 │

│ │ │ │Calcium oxide (CaO) │ 2.2 │ │ │ │ │Magnesium oxide (MgO) │ 0.9 │ │ │ │ │Sulphur trioxide (SO3) │ 1.0 │ │ │ │ │Available alkalies as N2O │ 0.44 │ │ │ │

│Loss on ignition (LOI) │ 2.5 │ │ │ │ │Moisture Content │ 0.3 │ └────────────────────────────────────┴────────────────────── ─┘ Table 3 - Trial Batch Concrete Mix

╔═══════╤════════════╤════════════════════════════════════════╗ ║ │ │ Weight of Material; lbs. per cu. yd. ║ ║ │ ├────────────┬─────────────┬─────────────╢ ║ Batch │ Net w/c │ │ s.s.d. │ s.s.d ║ ║ No. │Ratio by wt.│ Cement │ sand │ Gravel ║ ╟───────┼────────────┼────────────┼─────────────┼─────────────╢ ║ 1 │ 0.434 │ 722 │ 888 │ 2220 ║ ║ 2 │ 0.478 │ 575 │ 1085 │ 2200 ║ ║ 3 │ 0.600 │ 444 │ 1211 │ 2150 ║ ║ 4 │ 0.750 │ 365 │ 1330 │ 2060 ║ ╚═══════╧════════════╧════════════╧═════════════╧═════════════╝

19

Table 4 - Selected Concrete Mix Proportions ╔════════════════════════╤═════════════════════════════════════╗ ║ Design strength at │ Mix Proportions in lb./cu. ft. ║ ║ 28 days & 73 F. ├───────┬───────┬────────┬────────────╢

║ in psi. │Cement │ Sand │ Gravel │et w/c ratio║ ╟────────────────────────┼───────┼───────┼────────┼────────────╢ ║ 2500 │ 13.42 │ 49.25 │ 76 │ 0.76 ║ ║ 4500 │ 17.25 │ 44.00 │ 80.5 │ 0.57 ║ ╚════════════════════════╧═══════╧═══════╧════════╧════════════╝

20

Table 5 - Notations Used in Concrete Designations The concrete designated by the letters A and B were designed for 2500 psi and 4500 psi at 28 days and 73 F respectively. The subscripts 0, 10, 20 and 30 designate percentage fly ash replacement by weight of cement. Subscript LW designates concrete designed according to procedure suggested by Lovell and Washa [2]. Subscript Ex designates concrete designed with less water required for a 1 inch Kelly ball reading.

21

Table 6 - Properties of Concrete ═════════════════════════════════════════════════════════════════ Temp. Concrete % Kelly Wt. oz. fresh Wt. of hard- Designation* air Ball conc., in ened conc. in in. lb./cu. ft. lb./cu. ft. ───────────────────────────────────────────────────────────────── A

o 1.3 1 150.0

A10 1.0 1 151.6

A20 0.8 1-1/2 150.0

A30 1.3 1-1/2 150.8

ALW 1.3 1 150.4

73 AEX 1.0 1 151.6

Bo 0.6 1 152.3

B10 0.5 1-1/4 152.9

B20 0.9 1 151.9

B30 1.1 1-1/4 152.0

BEX 1.1 1 151.6

_________________________________________________________________ A

o 1.4 1 148.4 147.1

A10 1.0 1 149.6 147.5

A20 0.8 1-1/2 149.6 147.0

A30 0.8 1-3/4 149.6 147.2

ALW 1.4 1 149.2 148.5

95 AEX 0.6 1 149.6 147.4

Bo 1.2 1 150.4 148.6

B10 0.8 1 150.0 149.3

B20 0.4 1-1/4 150.8 149.0

B30 0.5 1-3/4 150.0 148.5

BEX 0.4 1 151.2 149.5

_________________________________________________________________ A

o 1.8 1 149.6 147.7

A10 1.4 1 148.4 146.5

A20 1.3 1-1/4 149.6 146.3

A30 2.0 1-3/4 149.6 146.5

ALW 1.4 3/4 150.4 147.6

120 AEX 1.2 1 150.0 147.5

Bo 1.7 1 150.0 147.8

B10 1.2 1 151.0 147.5

B20 1.1 1 150.6 147.7

B30 - 1 - 147.7

═════════════════════════════════════════════════════════════════ *The notations for concrete designation are described in Table 5.

22

Table 7 - Compressive Strength Data ══════════════════════════════════════════════ Temp. Conc. Compressive Strength psi F. Desig.* 7 day 28 day 90 day ══════════════════════════════════════════════

A10 1460 2580 2970

A20 1180 2000 2665

A30 1170 2285 2745

AEX 1380 2250 2900

73 ALW 1855 3240 3450

Bo 2780 4675 4830

B10 2895 4820 5310

B20 2475 3815 4785

B30 1935 3125 3685

BEX 2290 3765 4435

______________________________________________ A

O 1680 2400 -

A10 1660 2460 -

A20 1490 2315 -

A30 1315 2405 -

AEX 1360 2485 -

95 ALW 2280 3810 -

Bo 3115 4355 -

B10 2555 3945 -

B20 2535 3950 -

B30 2110 3435 -

BEX 2340 3785 -

______________________________________________ A

o 1860 2420 2795

A10 1830 2530 2785

A20 1470 2630 2450

A30 1615 2500 2620

AEX 1770 2630 2740

120 ALW 3325 3565 3990

Bo 2900 3975 3840

B10 2760 3865 4045

B20 2890 3875 3940

B30 2375 3340 3685

═══════════════════════════════════════════════ * The notations for concrete designation are described in Table 5.

23

Table 8 - Bond Strength Data ═════════════════════════════════════════════════════════════════ Ultimate Bond Bond stress, psi at a

Temp. Concrete Strength psi slip of 60x10-4 in at oF Designation* 28 day Loaded end, 28 day

_________________________________________________________________ A

o 1380 1105

73 A10 1580 1235

A20 1415 1040

A30 1370 1068

_________________________________________________________________ A

o 1630 1120

A10 1655 1270

95 A20 1610 1245

A30 1485 1220

_________________________________________________________________ A

o 1520 1170

A10 1550 1185

120 A20 1590 1295

A30 1560 1235

═════════════════════════════════════════════════════════════════ * The notations for concrete designation are described in Table 5.

24

Center for By-Products Utilization CONCRETE COMPRESSIVE STRENGTH, SHRINKAGE AND BOND STRENGTH AS AFFECTED BY ADDITION OF FLY ASH AND TEMPERATURE By Tarun R. Naik, Shiw S. Singh and Vasanthy Sivasundaram

Report No. CBU-1989-11

1989

Department of Civil Engineering and Mechanics College of Engineering and Applied Science THE UNIVERSITY OF WISCONSIN - MILWAUKEE