Appendix A

APPENDIX A Proportioning of the Concrete Mix

JOB SPECIFICATION

Type of Construction Beam

Exposure Mild, Non-air entrained

Maximum Aggregate Size ¾”

Slump 3”-4”

Specified f’c at 28 days 4500 psi

MATERIAL CHARACTERISTICS

Properties Cement Sand Gravel

Bulk Specific Gravity 3.15 2.40 2.8

Bulk Density, kg/m3(lb/ft

3) 3150 (196) 2400 (150) 2800 (175)

Dry-rodded Unit Weight, kg/m3(lb/ft

3) - - 1574 (98)

Fineness Modulus - 2.50 -

Moisture Deviation - +1.4% +0.3%

STEP 1 SLUMP

Table A-1 Recommended Slumps for Various Types of Construction*

Slump, mm (in)

Concrete Construction Maximum** Minimum

Reinforced foundation walls and footings 75 (3) 25 (1)

Plain footings, caissons, and substructure walls 75 (3) 25 (1)

Beams and reinforced walls 100 (4) 25 (1)

Building columns 100 (4) 25 (1)

Pavements and slabs 75 (3) 25 (1)

Mass Concrete 75 (3) 25 (1)

*American Concrete Institute (ACI 211.1)

** May be increased 25 mm (1 in) for consolidation by hand methods such as rodding and spading. Plasticizers can

safely provide higher slumps.

Based on the given, a 3”-4” slump range is desired and Table A-1 suggests a range of 1”-4” for

beams. Hence, a slump of 3”- 4” is to be required.

STEP 2 Maximum Aggregate Sizes (MAS)

¾ “as maximum aggregate size is to be used as stated in the given.

STEP 3 Water Content

Table A-2 suggests that for MAS of ¾” and non-air entrained concrete a water content of 340lb

per yd3 of concrete should be used. Approximate air content as obtained in Table A-3 is 2.0%.

Table A-2 Approximate Mixing Water in kg/m3 (lb/yd

3) for Different Slumps and Nominal Maximum Aggregate

Sizes*

Nominal Maximum Aggregate Size in mm (in)**

Slump,

mm(in)

9.5 (3/8) 12.5 (1/2) 19 (3/4) 25 (1) 40 (1 ½) 50 (2)*** 75 (3)*** 150 (6)***

Non-air-entrained Concrete

25 to 50

(1 to 2)

207 (350) 199 (335) 190 (315) 179 (300) 166 (275) 154 (260) 130 (220) 113 (190)

75 to 100

(3 to 4)

228 (385) 216 (365) 205 (340) 193 (325) 181 (300) 169 (285) 145 (245) 124 (210)

150 to 175

(6 to 7)

243 (410) 228 (385) 216 (360) 205 (340) 190 (315) 178 (300) 160 (270) ______

Air-entrained Concrete

25 to 50

(1 to 2)

181 (305) 175 (295) 168 (280) 160 (270) 150 (250) 142 (240) 122 (205) 107 (180)

75 to 100

(3 to 4)

202 (340) 193 (325) 184 (305) 175 (295) 165 (275) 157 (265) 133 (225) 119 (200)

150 to 175

(6 to 7)

216 (365) 205 (345) 197 (325) 184 (310) 174 (290) 166 (280) 154 (260) ______

*American Concrete Institute (ACI 211.1 and ACI 318)

** These quantities of mixing water are for use in computing cementitious material contents for trial batches. They are

maximums for reasonably well-shaped angular coarse aggregates graded within limits of accepted specifications.

*** The slump values for concrete containing aggregates larger than 40 mm (1 ½ in) are based on slump tests made

after removal of particles larger than 40 mm by wet screening.

Table A-3 Approximate Target Percent Air Content Requirements for Different Nominal Maximum Sizes of

Aggregates*

Nominal Maximum Aggregate Size (in)

3/8 ½ ¾ 1 1 ½ 2 3 6

Non- air-entrained Concrete 3 2.5 2 1.5 1 0.5 0.3 0.2

Air-entrained Concrete**

Mild Exposure 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0

Moderate Exposure 6.0 5.5 5.0 4.5 4.5 4.0 3.5 3.0

Severe Exposure 7.5 7.0 6.0 6.0 5.5 5.0 4.5 4.0


** The air content in job specifications should be specified to be delivered within -1 to +2 percentage points of the

table target value for moderate and severe exposures

STEP 4 Water/ Cement Ratio

Since no studies were conducted to determine the standard deviation of the compressive

strength of concrete prior to this experiment, we use the suggested increase in strength given in

Table A-4. That is, the specified strength 4500psi is increased to 5700psi. Interpolating from

Table A-5, we have a W/C equal to 0.43.

Table A-4 Increase in Strength for Different Specified Strengths

(Standard Deviation Not Available)

Specified Compressive Strength (f’c) Required Increase in Strength

MPa psi Mpa psi

<21 <3000 7 1000

21-35 3000-5000 8.5 1200

>35 >5000 10.0 1400

Table A-5 Typical Relationship Between W/C Ratio and Compressive Strength of Concrete*

W/C by Mass

Average 28-day Compressive

Strength, MPa (psi)

Non-Air -Entrained

Air-Entrained

48 (7000) 0.33 -

41 (6000) 0.41 0.32

35 (5000) 0.48 0.40

28 (4000) 0.57 0.48

21 (3000) 0.68 0.59

14 (2000) 0.82 0.74

*American Concrete Institute (ACI 211.1 and ACI 211.3)

** Strength is based on cylinders moist-cured 28 days in accordance to ASTM C31

[AASHTO T23]. Relationship assumes nominal MAS about (3/4 in to 1 in)

STEP 5 Cement Content

The cement content is given for a 1yd3 concrete is given by:

C = W/ (W/C) = 340 lb/ 0.43 = 790.70 lb

STEP 6 Weight of Gravel

Using Table A-6, we find the volume fraction of gravel by interpolation. Hence, for an FM of

2.50, a concrete of MAS ¾” has a volume fraction of 0.65. Consequently, the dry-rodded volume

of gravel is 17.55 ft3. Moreover, the weight of gravel therefore is given by: G = (17.55 ft3) (98

lb/ft3) = 1719.90 lb.

Table A-6 Bulk Volume of Coarse Aggregates per Unit Volume of Concrete*

MAS, mm(in) Bulk Volume of Dry-Rodded Coarse Aggregate Per Unit Volume of Concrete for

Different Fineness Moduli of Fine Aggregate**

Fineness Modulus

2.40 2.60 2.80 3.00

9.5 (3/8) 0.50 0.48 0.46 0.44

12.5 ( ½) 0.59 0.57 0.55 0.53

19 (¾) 0.66 0.64 0.62 0.60

25 (1) 0.71 0.69 0.67 0.65

37.5 (1 ½) 0.75 0.73 0.71 0.69

50 (2) 0.78 0.76 0.74 0.72

75 (3) 0.82 0.80 0.78 0.76

150 (6) 0.87 0.85 0.83 0.81


** Bulk Volumes are based on aggregates in a dry-rodded condition as described in ASTM C29 [AASHTO T19]

STEP 7 Weight of Sand

Using Absolute Volume Method for a 27 ft3 concrete, we have the following:

Total = ( )

STEP 8 Moisture Corrections Applying moisture corrections for the sand and gravel components, we have the table below:

Material Calculated Weight

(lb)

Moisture Correction Corrected Weight

(lb)

C 790.70 790.70

S 1069.29 +0.014(1069.29) 1084.26

G 1719.90 +0.003(1719.90) 1725.06

W 340 -0.014(1069.29)- 0.003(1719.90) 319.87

3919.89 3919.89

STEP 9 Trial Batch Adjustments

The trial batch has a total volume of . We then need to increase in

volume about 20% from the total volume of molds. Finally, we proportion the concrete mix to

this trial volume.

Summary

Batch Ingredients Weight Required for the 9 Molds

Water 7.44lb

Cement 18.40lb

Fine Aggregate 40.14lb

Coarse Aggregate 25.23lb

University of the Philippines Diliman

College of Engineering

Institute of Civil Engineering

2nd Term A.Y. 2012-2013

CE 121 TL1 Laboratory Report #4:

Proportioning, Batching, Mixing, and Testing of

Portland Cement Concrete

Submitted by:

Arvin D. Sanchez

2009-24184

Submitted to:

Nathaniel B. Diola, Dr. Eng

Instructor

I. Objectives

Civil and construction engineers are primarily concerned for the quality control of Portland cement

concrete and the mix proportions used for it. The quality of concrete is directly affected by the extent

of chemical reactions produced by its components. For example, the quality is controlled by the

composition of the Portland cement used, rate of hydration and development of microstructure, ad-

mixtures and aggregate composition. The methods of mixing, transporting, placing, and curing of

concrete strongly affect the serviceability of the structure developed from the mix. It is also true that

the ingredients of “good” concrete and those that constitute “bad” concrete may be the same but the

difference resides on the expertise of the ones handling the concrete during construction. (Mamlouk

and Zaniewski, 2011)

Proportioning of concrete mixes are of crucial importance whether on the solid or plastic state. Dur-

ing the plastic state, the main concern of the engineer is the workability and finishing characteristics

of the concrete. Proper batching, mixing and handling of fresh concrete contribute to the strength

and durability of concrete structures.

Curing is the process of maintaining the desired moisture and temperature condition necessary for

hydration of cement for a definite period of time. Proper curing not only increases strength, but also

provides durability, water tightness, abrasion resistance, volume stability and freeze-thaw re-

sistance. The choice of curing method depends on availability of curing material, size and shape of

the structure, economics, and aesthetics.

Concrete as a material for construction is usually utilized for the design of compression members.

Compressive strength is one the structural design specifications necessary in ensuring that the

structure can carry the intended load. Hence, the compressive strength is the most commonly per-

formed test on hardened concrete.

From a job description given to the control group, the experiment aims to properly proportion, batch,

mix, cure and test the concrete for compression. Results of compression testing are to be evaluated

with respect to the standards of DPWH and ACI.

II. Experimental Procedure

A. Materials and Equipment used

A weighing balance or scale accurate within 0.1% of the sample having at least 0.05kg (0.11lb)

graduation was used extensively for determining masses. In ensuring the coarse aggregate sample

to have a nominal maximum size of 3/4 in. but not to pass sieve No. 4, the sample is sieved in

sieves of size 3/4in. and 4.75mm. For the fine aggregate, the sieve no. 200 is used to ensure that

no particles should pass. A mechanical mixer is used to aid mixing of concrete. A tamping rod made

of steel having a length of 60mm and diameter of approximately 16mm was used in striking the

fresh concrete mass in the measure in determining the slump. Nine cylindrical metal molds having a

height of approximately equal to twice its diameter are used for hardening fresh concrete to desired

testing size and shape. A curing pond is then used to immerse the concrete specimens until the day

of testing. In testing the compressive strength of the specimens, a testing machine as required by

ASTM C192 or ASTM C31 was used with the aid of the laboratory technician.

B. Methodology

Proportioning of the Concrete Mix:

The 9 step concrete mix design procedure suggested by ACI was implemented in this procedure.

Figure 1 illustrates the summary of the procedure. The proportioning of the trial mix for this experi-

ment is completely shown in Appendix A.

Figure 1 Summary of ACI mix design procedure

Batching the Proportioned Concrete Mix:

Concrete should be mixed thoroughly either by hand or in a mixer, until uniform consistency is

achieved. The concrete in this experiment was batched by weight to eliminate problems created by

bulking of damp sand. The mixer was first charged with 10% of the water, followed by uniform addi-

tion of fines and cementitious materials. Incrementing the amount of water until 80%, the mixer was

allowed to mix the materials for about 3 minutes. Then, a 2-minute period of setting was allowed to

scrap all unmixed materials. Next, all of the gravel mass was put into the mix and mixed thoroughly

up to 3 minutes. Again, a 2-minute setting is allowed to be able to make a slump test of the fresh

concrete. After checking that the required slump is achieved, the specimen tested for slump was put

back into the mixer and was allowed to mix with the remaining material inside. Lastly, the fresh con-

crete mix was distributed into the 4” diameter by 8” height cylindrical molds for testing following

ASTM C39.

If the slump is not given, decide the slump using Table

A-1

Decide the maximum size of aggregate; choose the maximum possible size using the following

guidelines:

maximum size > 1/5 narrowest dimension between forms.

> 1/3 depth of slab

> 3/4 clear spacing between reinforcing bars.

Decide the amount of water and air content based on

Tables A-2 and A-3

Select the W/C ratio on Table A-5

Calculate Cement Content, C

C= W/(W/C)

Choose the amount of coarse aggregate using Table

A-6

Calculate the amount of fines using absolute volume method and adjust for

moisture content in the aggregates used. Then adjust for the trial mix.

Slump Test:

In the slump test, the concrete in the plastic state is formed into a conical metal mold as described

in ASTM C143. At each incremental level, the mix is tamped up to 25 strokes. The mold was then

lifted, leaving the concrete to spread or to drop in height. The drop in height measured from the in-

verted conical mold to the center of the slumped concrete will be the slump measure of the degree

of workability of the fresh concrete. An illustration of the slump test is shown in Figure 2.

Figure 2 Illustration of the Slump Test

Curing and Testing of Concrete Specimens:

Curing should start after the final set of the cement. Not curing concrete after setting results to

shrinkage which eventually leads to cracking. After the surface of the fresh concrete is finished,

specimens are kept in the mold for the first 24±8h. Specimens are then removed from the molds

and cured at temperature of 23±1.70C (73.4±30F) by immersion in saturated-lime water until the time

of testing. Using a testing machine, specimens are axially loaded by compression with a specified

rate of loading until failure. The specimen compressive strength is calculated using Equation (1).

Three specimens are tested for each test age (i.e. 7-day, 14-day, and 28-day testing ages).

(1)

where, is the compressive strength of the specimen in psi, P is the ultimate compressive load in

lb and in2 is the cross sectional area of the specimen

III. Results and Discussion

Table 1 summarizes the concrete mix proportion used for 10.8 times the volume of a single

cylindrical mold (i.e. 0.6283 ft3). The strength specified for the control group is 4500psi. For detailed

calculation steps for this proportion see Appendix A.

Table 1 Concrete Mix Proportion Used for Batching

Batch Proportions


Water 7.44lb

Cement 18.40lb



Using the proportions stated in Table 1 for mixing, the fresh concrete tested for workability gives a

slump of 3” which is within the specified range as given in the job description. The obtained slump is

the stiffest workable consistency for the desired mix. The 9 specimens were divided into 3 batches

for testing: 3 specimens for each testing age (i.e. 7, 14, and 28 day test). The specimens were

cured in the curing tank until the day of testing. The test results for ultimate compressive strength of

the specimens were summarized in Table 2.

The specified strength given for the experimental group has been attained as early as the 14th day

of curing. That is, the average strength at the 14th day test is already greater than 4500psi.

Table 2 Compressive Test Results for the Laboratory Prepared Specimens

Compressive Strength of Proportioned Concrete for Different Day of Testing

Day of Testing Specimen # Diameter (in) Height (in) L/D Ultimate Load (lb) Strength (psi)

1 4 7.875 1.96875 51500 4100

7 2 4 7.875 1.96875 52500 4180

3 4 7.875 1.96875 54000 4300

AVERAGE= 4190

STD DEV= 100

1 4 7.875 1.96875 57500 4580

14 2 4 7.9375 1.984375 56500 4500

3 4 7.9375 1.984375 56000 4460

AVERAGE= 4510

STD DEV= 60

1 4 7.875 1.96875 58500 4660

7 2 4 7.875 1.96875 61500 4890

3 4 7.875 1.96875 62000 4930

AVERAGE= 4830

STD DEV= 150

The 28-day average compressive strength is 4830psi which is about 830psi greater than that of the

specified strength. Considering only the test results, this is very satisfactory. But, the mix is of higher

cost than the target if it is for use in actual engineering projects. Take note that if the standard devia-

tion of the mix is needed, larger sample sizes must be tested.

Evaluating the 28-day result with respect to the DPWH standard, the concrete proportioned by the

group is acceptable because 3 consecutive strength tests results are all greater than the specified

strength. With respect to the ACI standard, the concrete is still acceptable for the average of all sets

of 3 consecutive tests is greater than the specified strength. Also, no individual test results fall below

the specified strength by 500psi.

For further analysis of the results, we consider the prediction equation given by Equation (2). Equa-

tion (2) reflects the relationship of the time of curing to the mean compressive strength at that test-

ing day. Let be the mean compressive strength at age t days, be the mean 28-day com-

pressive strength and t be testing age, days. (2)

Equation (2) is obtained empirically so that we can compare our results to verify this empirical rela-

tion. The use of the above equation gives us the following: for the 7-day curing period the strength is

predicted to be 3400psi while 4250 psi is for the 14-day test. Figure 3 shows the graphical represen-

tation of the data fitted with Equation (2). To achieve this, we plot vs t and setting a

y-intercept of 0. For the regression line, we expect that the coefficient that will appear corresponds

to . The 0.983 goodness of fit parameter tells us that the equation actually represents the data

and the data conforms to the empirical relation. It must be noted that fitting data with a trend line will

ask us to perform least squares analysis with the testing age and compressive strengths paired.

Figure 3 Plot of the Strength vs. Testing Age fitted with the empirical relation

IV. Conclusions and Recommendations

In this experiment, we have clearly seen that the accuracy of the concrete mix proportions greatly

affect the desired result for compressive testing. Miscalculations will surely give erroneous strength

results whether too low or too high than the specified strength. In our case, we have shown that the

ACI method for concrete mix design is indeed valid with the absolute volume method being the most

accurate.

y = 4913x

R² = 0,9837

0

20000

40000

60000

80000

100000

120000

140000

160000

0 5 10 15 20 25 30

fcm

(t)

{4+

0.8

5t}

, p

si.d

ay

t, day

Investigation of the Empirical Relation

Datenreihen1 Linear (Datenreihen1)

In batching the specimens for testing, we have noted the importance of properly choosing the ingre-

dients to be mixed. For the aggregates, a grading suggested by standards should be sought. Also,

the data for aggregates to be used for computations should be determined with great precision and

great accuracy. That is, the bulk densities, bulk specific gravities, dry-rodded unit weights, moisture

contents, fineness modulus etc. should be reported with the greatest possible accuracy meaning

previous experiments should be done ensuring minimization of errors as much as possible. The

cement should be sieve to ensure that there are no coagulated components present. Care in weigh-

ing should also be observed. In putting the fresh concrete in the molds, proper tamping should be

followed.

The results of the experiment were satisfactory in the context of our objective. That is, the 28-day

compressive strengths of the specimens are all greater than the specified strength. In projects, it is

recommended to optimize the cost of the mix in line with the proportions to be made. Lastly, con-

crete as a composite material derived from other construction materials is usually acceptable if all its

components were standardized making the complete mix standardized as well.

APPENDIX A Proportioning of the Concrete Mix

JOB SPECIFICATION

Type of Construction Beam

Exposure Mild, Non-air entrained

Maximum Aggregate Size ¾”

Slump 3”-4”

Specified f’c at 28 days 4500 psi

MATERIAL CHARACTERISTICS

Properties Cement Sand Gravel

Bulk Specific Gravity 3.15 2.40 2.8

Bulk Density, kg/m3(lb/ft

3) 3150 (196) 2400 (150) 2800 (175)

Dry-rodded Unit Weight, kg/m3(lb/ft

3) - - 1574 (98)

Fineness Modulus - 2.50 -

Moisture Deviation - +1.4% +0.3%

STEP 1 SLUMP

Table A-1 Recommended Slumps for Various Types of Construction*

Slump, mm (in)

Concrete Construction Maximum** Minimum

Reinforced foundation walls and footings 75 (3) 25 (1)

Plain footings, caissons, and substructure walls 75 (3) 25 (1)

Beams and reinforced walls 100 (4) 25 (1)

Building columns 100 (4) 25 (1)

Pavements and slabs 75 (3) 25 (1)

Mass Concrete 75 (3) 25 (1)


** May be increased 25 mm (1 in) for consolidation by hand methods such as rodding and spading. Plasticizers can safely

provide higher slumps.

Based on the given, a 3”-4” slump range is desired and Table A-1 suggests a range of 1”-4” for

beams. Hence, a slump of 3”- 4” is to be required.

STEP 2 Maximum Aggregate Sizes (MAS)

¾ “as maximum aggregate size is to be used as stated in the given.

STEP 3 Water Content

Table A-2 suggests that for MAS of ¾” and non-air entrained concrete a water content of 340lb per

yd3 of concrete should be used. Approximate air content as obtained in Table A-3 is 2.0%.

Table A-2 Approximate Mixing Water in kg/m3 (lb/yd

3) for Different Slumps and Nominal Maximum Aggregate Siz-

es*

Nominal Maximum Aggregate Size in mm (in)**

Slump,

mm(in)

9.5 (3/8) 12.5 (1/2) 19 (3/4) 25 (1) 40 (1 ½) 50 (2)*** 75 (3)*** 150 (6)***

Non-air-entrained Concrete

25 to 50

(1 to 2)

207 (350) 199 (335) 190 (315) 179 (300) 166 (275) 154 (260) 130 (220) 113 (190)

75 to 100

(3 to 4)

228 (385) 216 (365) 205 (340) 193 (325) 181 (300) 169 (285) 145 (245) 124 (210)

150 to 175

(6 to 7)

243 (410) 228 (385) 216 (360) 205 (340) 190 (315) 178 (300) 160 (270) ______

Air-entrained Concrete

25 to 50

(1 to 2)

181 (305) 175 (295) 168 (280) 160 (270) 150 (250) 142 (240) 122 (205) 107 (180)

75 to 100

(3 to 4)

202 (340) 193 (325) 184 (305) 175 (295) 165 (275) 157 (265) 133 (225) 119 (200)

150 to 175

(6 to 7)

216 (365) 205 (345) 197 (325) 184 (310) 174 (290) 166 (280) 154 (260) ______


** These quantities of mixing water are for use in computing cementitious material contents for trial batches. They are

maximums for reasonably well-shaped angular coarse aggregates graded within limits of accepted specifications.

*** The slump values for concrete containing aggregates larger than 40 mm (1 ½ in) are based on slump tests made after

removal of particles larger than 40 mm by wet screening.

Table A-3 Approximate Target Percent Air Content Requirements for Different Nominal Maximum Sizes of Aggre-

gates*

Nominal Maximum Aggregate Size (in)

3/8 ½ ¾ 1 1 ½ 2 3 6

Non- air-entrained Concrete 3 2.5 2 1.5 1 0.5 0.3 0.2

Air-entrained Concrete**

Mild Exposure 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0

Moderate Exposure 6.0 5.5 5.0 4.5 4.5 4.0 3.5 3.0

Severe Exposure 7.5 7.0 6.0 6.0 5.5 5.0 4.5 4.0


** The air content in job specifications should be specified to be delivered within -1 to +2 percentage points of the table

target value for moderate and severe exposures

STEP 4 Water/ Cement Ratio

Since no studies were conducted to determine the standard deviation of the compressive strength of

concrete prior to this experiment, we use the suggested increase in strength given in Table A-4.

That is, the specified strength 4500psi is increased to 5700psi. Interpolating from Table A-5, we

have a W/C equal to 0.43.

Table A-4 Increase in Strength for Different Specified Strengths

(Standard Deviation Not Available)

Specified Compressive Strength (f’c) Required Increase in Strength

MPa psi Mpa psi

<21 <3000 7 1000

21-35 3000-5000 8.5 1200

>35 >5000 10.0 1400

Table A-5 Typical Relationship Between W/C Ratio and Compressive Strength of Concrete*

W/C by Mass

Average 28-day Compressive

Strength, MPa (psi)

Non-Air -Entrained

Air-Entrained

48 (7000) 0.33 -

41 (6000) 0.41 0.32

35 (5000) 0.48 0.40

28 (4000) 0.57 0.48

21 (3000) 0.68 0.59

14 (2000) 0.82 0.74

*American Concrete Institute (ACI 211.1 and ACI 211.3)

** Strength is based on cylinders moist-cured 28 days in accordance to ASTM C31

[AASHTO T23]. Relationship assumes nominal MAS about (3/4 in to 1 in)

STEP 5 Cement Content

The cement content is given for a 1yd3 concrete is given by:

C = W/ (W/C) = 340 lb/ 0.43 = 790.70 lb

STEP 6 Weight of Gravel

Using Table A-6, we find the volume fraction of gravel by interpolation. Hence, for a FM of 2.50, a

concrete of MAS ¾” has a volume fraction of 0.65. Consequently, the dry-rodded volume of gravel is

17.55 ft3. Moreover, the weight of gravel therefore is given by: G = (17.55 ft3) (98 lb/ft3) = 1719.90

lb.

Table A-6 Bulk Volume of Coarse Aggregates per Unit Volume of Concrete*

MAS, mm(in) Bulk Volume of Dry-Rodded Coarse Aggregate Per Unit Volume of Concrete for

Different Fineness Moduli of Fine Aggregate**

Fineness Modulus

2.40 2.60 2.80 3.00

9.5 (3/8) 0.50 0.48 0.46 0.44

12.5 ( ½) 0.59 0.57 0.55 0.53

19 (¾) 0.66 0.64 0.62 0.60

25 (1) 0.71 0.69 0.67 0.65

37.5 (1 ½) 0.75 0.73 0.71 0.69

50 (2) 0.78 0.76 0.74 0.72

75 (3) 0.82 0.80 0.78 0.76

150 (6) 0.87 0.85 0.83 0.81


** Bulk Volumes are based on aggregates in a dry-rodded condition as described in ASTM C29 [AASHTO T19]

STEP 7 Weight of Sand

Using Absolute Volume Method for a 27 ft3 concrete, we have the following:

Total = ( )

STEP 8 Moisture Corrections Applying moisture corrections for the sand and gravel components, we have the table below:

Material Calculated Weight

(lb)

Moisture Correction Corrected Weight

(lb)

C 790.70 790.70

S 1069.29 +0.014(1069.29) 1084.26

G 1719.90 +0.003(1719.90) 1725.06

W 340 -0.014(1069.29)- 0.003(1719.90) 319.87

3919.89 3919.89

STEP 9 Trial Batch Adjustments

The trial batch has a total volume of . We then need to increase in vol-

ume about 20% from the total volume of molds. Finally, we proportion the concrete mix to this trial

volume.

Summary


Water 7.44lb

Cement 18.40lb



References:

Mamlouk, M.S. and Zaniewski, J.P.; Materials for Civil and Construction Engineers 3rd ed.; Pearson Educa-

tion Inc.; 2011.

ASTM C31/C31M-03a; Standard Practice for Making and Curing Concrete Test Specimens in the Field

ASTM C39/C39M-12a; Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens

Online References:

http:// www.ce.memphis.edu/1112/notes/project_2/beam/ACI_mix_design.pdf

http://classes.engr.oregonstate.edu/cce/winter2012/ce492/Modules/05_mix_design/05-8_body.htm

Appendix A

Documents

Transcript of Appendix A