2002 Design

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IRC: 15-2002 – Standard specifications and code of practice for. Construction of concrete road (third. Revision) 9: Kishore Kaushal, “Concrete Mix Design Based on Flexural Strength for Air-Entrained Concrete”, Proceeding of 13 th Conference on our World in Concrete and Structures, 25-26, August, 1988, Singapore. This study is particularly suitable for a case study design because it is a bounded system, it is contextual, and it is a study of process (Merriam, 1998). Like Creswell (2002), Stake (2000) defines case study as the study of a 'bounded system' (p.

The objective of this research is to develop the calibration procedure for the American Association of State Highway and Transportation Officials (AASHTO) 2002 design guide models for both flexible and rigid pavement structures for this region and to assist the state highway agencies in region in the implementation of the new Guide for pavement design and surface selection practices.

  • Record URL:
      http://www.pooledfund.org/Details/Study/301
  • Supplemental Notes:
    • Pooled fund project. Published as FHWA-KS-16-16 - January 2017.

Language

Aashto 2002 Design Guide

  • English

Project

  • Status: Completed
  • Funding: $562000
  • Contract Numbers:

    TPF-5(079)

  • Sponsor Organizations: Eisenhower State Office Building
    700 SW Harrison Street
    Topeka, KS United States 66603-3754

    New York State Department of Transportation

    50 Wolf Road
    Albany, NY United States 12232
  • Project Managers:

    Barker, Susan

  • Performing Organizations:

    Kansas State University

    148 Rathbone Hall
    Manhattan, KS United States 66506
  • Principal Investigators:

    Hossain, Mustaque

    Romanoschi, Stefan

  • Start Date: 20031001
  • Expected Completion Date: 20151231
  • Actual Completion Date: 0
  • Source Data: RiP Project 42088

Subject/Index Terms

  • TRT Terms: Calibration; Flexible pavements; Guidelines; Implementation; Pavement design; Pavement management systems; Rigid pavements; State departments of transportation
  • Identifier Terms: AASHTO 2002 Design Guide
  • Subject Areas: Design; Highways; Pavements; Policy;

Filing Info

  • Accession Number: 01553833
  • Record Type: Research project
  • Source Agency: Federal Highway Administration
  • Contract Numbers: TPF-5(079)
  • Files: RiP, STATEDOT
  • Created Date: Feb 24 2015 1:00AM

By
Er. Kaushal Kishore ,
Materials Engineer, Roorkee

ABSTRACT:
The stresses induced in concrete pavements are mainly flexural. Therefore flexural strength is more often specified than compressive strength in the design of concrete mixes for pavement construction. A simple method of concrete mix design based on flexural strength for normal weight concrete mixes is described in the paper.

INTRODUCTION:
Usual criterion for the strength of concrete in the building industry is the compressive strength, which is considered as a measure of quality concrete. however, in pavement constructions, such as highway and airport runway, the flexural strength of concrete is considered more important, as the stresses induced in concrete pavements are mainly flexural. Therefore, flexural strength is more often specified than compressive strength in the design of concrete mixes for pavement construction. It is not perfectly reliable to predict flexural strength from compressive strength. Further, various codes of the world specified that the paving concrete mixes should preferably be designed in the laboratory and controlled in the field on the basis of its flexural strength. Therefore, there is a need to design concrete mixes based on flexural strength.


The type of aggregate can have a predominant effect, crushed rock aggregate resulting in concrete with higher flexural strength than uncrushed (gravel) aggregates for comparable mixes, assuming that sound materials are used. The strength of cement influences the compressive and flexural strength of concrete i.e. with the same water-cement ratio, higher strength cement will produce concrete of higher compressive and flexural strength.

MIX DESIGN DETAILS
IRC: 15-2002 specified that for concrete roads OPC should be used. This code also allowed PPC as per IS: 1489 may also be used. Accordingly OPC + fly ash may be used in concrete roads. However, IS: 456-2000 specified that fly ash conforming to grade-1 of IS-3812 may be used as part replacement of OPC provided uniform blended with cement is essential. The construction sites where batching plants are used this may be practicable. In ordinary sites where mixer or hand mixing are done uniform blending of fly ash with cement is not practicable. At such construction sites, PPC may be used.

1Characteristic Flexural Strength at 28 days4.5N/mm2
2CementThree mixes are to be designed
MIX-A
With PPC (Flyash based) conforming to IS:1489-part-I-1991. 7 days strength 37.5N/mm2. Specific Gravity: 3.00
MIX-B
With OPC-43- Grade conforming to IS: 8112-1989. 7 days strength 40.5N/mm2. Specific Gravity : 3.15
MIX-C
With OPC of Mix-B and Fly ash conforming to IS:3812 (Part-I)-2003 Specific Gravity : 2.20
Note Requirements of all the three mixes are the same. Fine Aggregate, Coarse Aggregate and Retarder Super plasticizer are the same for all the three mixes.
3Fly ash replacement25% Fly ash is required to be replaced with the total cementitious materials.
4Maximum nominal size of aggregates20 mm Crushed aggregate
5Fine aggregateRiver sand of Zone-II as per IS:383-1970
6Minimum cement content350 kg/m3 including Fly ash
7Maximum free W/C Ratio0.50
8Workability30 mm slump at pour the concrete will be transported from central batching plant through transit mixer, at a distance of 20 Km during June, July months. The average temperature last year during these months was 400C.
9Exposure conditionModerate
10Method of placingFully mechanized construction
11Degree of supervisionGood
12Maximum of cement content (Fly ash not included)425 kg/m3
13Chemical admixtureRetarder Super plasticizer conforming to IS:9103-1999. With the given requirements and materials, the manufacturer of Retarder Super plasticizer recommends dosages of 10 gm per kg of OPC, which will reduce 15% of water without loss of workability. For fly ash included cement dosages will be required to be adjusted by experience/ trials.
14Values of Jaxo-1.65 x 0.5 N/mm2

TEST DATA FOR MATERIALS AND OTHER DETAILS
1. The grading of fine aggregate, 10 and 20 mm aggregates are as given in Table. 1 ( given in the end). Fine aggregate is of zone-II as per IS:383-1970. 10 and 20 mm crushed aggregate grading are single sized as per IS: 383-1970.

2. Properties of aggregates

Tests

Fine aggregate

10mm aggregate

40mm aggregate

Specific Gravity

2.65

2.65

2.65

Water Absorption %

0.8

0.5

0.5

3. Target average flexural strength for all A, B and C mixes
S = S+ Jao-
= 4.5 + 1.65 x 0.5
= 5.3 N/mm2 at 28 days age

4. For Mix A and B free W/C ratio with crushed aggregate and required average flexural target strength of 5.3 N/mm2 at 28 days from Fig. 1 Curve D ( Figure shown in the end) found to be 0.42. This is lower than specified maximum W/C ratio value of 0.50
Note: In absence of cement strength, but cement conforming to IS Codes, assume from Fig. 1

Curve A and B – For OPC 33 Grade
Curve C and D – For OPC 43 Grade

Take curves C and D for PPC, as PPC is being manufactured in minimum of 43 Grade of strength.

5. Other data’s: The Mixes are to be designed on the basis of saturated and surface dry aggregates. At the time of concreting, moisture content of site aggregates are to be determine. If it carries surface moisture this is to be deducted from the mixing water and if it is dry add in mixing water the quantity of water required for absorption. The weight of aggregates are also adjusted accordingly.

DESIGN OF MIX-A WITH PPC
a) Free W/C ratio for the target flexural strength of 5.3 N/mm2 as worked out is 0.42

b) Free water for 30 mm slump from Table 2 for 20 mm maximum size of aggregate.
2/3*165 + 1/3*195
= 175 kg/m3

From trials it is found that Retarder Super plasticizer at a dosages of 15gm/kg of cement may reduce 15% water without loss of workability
Then water = 175 – (175 x 0.15) = 148.75 kg/m3
For trials say 149 kg/m3

c) PPC = 149/0.42 = 355 kg/m3
This is higher than minimum requirement of 350 kg/m3

d) Formula for calculation of fresh concrete weight in kg/m3

UM = 10 x Ga (100 – A) + CM(1 – Ga/Gc) – WM (Ga – 1)
Where,
Um = Weight of fresh concrete kg/m3

Ga = Weighted average specific gravity of combined fine and coarse aggregate bulk, SSD

Gc = Specific gravity of cement. Determine actual value, in absence assume 3.15 for OPC and 3.00 for PPC (Fly ash based)

A = Air content, percent. Assume entrapped air 1.5% for 20 mm maximum size of aggregate and 2.5% for 10mm maximum size of aggregate. There are always entrapped air in concrete. Therefore ignoring entrapped air value as NIL will lead the calculation of higher value of density.

Wm = Mixing water required in kg/m3

Cm = Cement required, kg/m3

Note:- The exact density may be obtained by filling and fully compacting constant volume suitable metal container from the trial batches of calculated design mixes. The mix be altered with the actual obtained density of the mix.

2002 Design

Um = 10 x Ga (100 – A) + Cm (1 – Ga/Gc) – Wm (Ga – 1)

= 10 x 2.65 (100 – 1.5) + 355(1- 2.65/3.00) – 149 (2.65 -1)
= 2405.9 kg/m3
Say 2405 kg/m3

e) Aggregates = 2405 – 355 – 149 = 1901 kg/m3

f) Fine aggregate = From Table 3 for zone-II Fine aggregate and
20 mm maximum size of aggregate, W/C ratio = 0.42, 30 mm slump found to be 35%.

Fine aggregate = 1901 x 0.35 = 665 kg/m3
Coarse aggregate = 1901 – 665 = 1236 kg/m3

10 and 20 mm aggregate are single sized as per IS: 383-1970. Let they be combined in the ratio of 1.2:1.8 to get 20 mm graded aggregate as per IS: 383-1970

10 mm aggregate = 1236×1.2/3 = 494 kg/m3
20 mm aggregate = 1236×1.8/3 = 742 kg/m3

g) Thus for 4.5 N/mm2 flexural strength quantity of materials per cu.m. of concrete on the basis of saturated and surface dry aggregates:

Water = 149 kg/m3
PPC = 355 kg/m3
Fine Aggregate (sand) = 665 kg/m3
10 mm Aggregate = 494 kg/m3
20 mm Aggregate = 742 kg/m3
Retarder Super Plasticizer = 5.325 kg/m3

MIX- B WITH OPC
a) Water = 175 – (175 x 0.15) = 149 kg/m3 say 149 kg/m3

b) OPC = 149/0.42 = say 355 kg/m3

c) Density: 10 x 2.65 (100 – 1.5) + 355 (1 – 2.65/3.15) – 149 (2.65 – 1)
= 2420.8 kg/m3 say 2420 kg/m3

d) Total Aggregates = 2420 – 355 – 149 = 1916 kg/m3
Fine Aggregate = 1916 x 0.35 = say 670 kg/m3
Coarse aggregate = 1916 – 670 = 1246 kg/m3
10 mm Aggregate = 1246×1.2/3 = 498 kg/m3
20 mm Aggregate = 1246×1.8/3 = 748 kg/m3

e) Thus for 4.5 N/mm2 flexural strength quantity of materials per cu.m of concrete on the basis of SSD aggregates are given below:

Water = 149 kg/m3
OPC = 355 kg/m3
Fine Aggregate (sand) = 670 kg/m3
10 mm Aggregate = 498 kg/m3
20 mm Aggregate = 748 kg/m3
Retarder Super Plasticizer = 3.550 kg/m3

MIX. C WITH OPC + FLYASH
With the given set of materials increase in cementitious materials = 10.7%
Total cementitious materials = 355×1.107 = 393 kg/m3

Materials

Weight (kg/m3)

Volume (m3)

OPC = 393 x 0.75

295/3150

0.0937

Flyash = 393 x 0.25

98/2200

0.0445

Free Water = 149 x 0.95

142/1000

0.142

Retarder Super Plasticizer = 6.2 kg

6.2/1150

0.0054

Air = 1.5%

0.015

Total

0.3006

Total Aggregates = 1 – 0.3006

0.6994

Coarse Aggregate

1246/2650

0.4702

Fine Aggregate = 0.6994 – 0.4702 = 0.2292
= 0.2292 x 2650 = 607 kg

Note:-
1. Specific gravity of Normal Superplasticizer = 1.15
2. Addition of Flyash reduces 5% of water demand.

For 4.5 N/mm2 flexural strengthquantity of material per cu.m of concrete on the basis of saturated and surface dry aggregates of

Mix ‘A’, ‘B’ and ‘C’ are given below:

Materials

MIX. ‘A’ with PPC

Mix. ‘B’ with OPC

Mix. ‘C’ with OPC+Flyash

Water kg/m3

149

149

142

PPC kg/m3

355

OPC kg/m3

355

295

Flyash kg/m3

98

Fine Agg. kg/m3

665

670

607

10mm Agg. kg/m3

494

498

498

20 mm Agg. kg/m3

742

748

748

Retarder Super- plasticizer kg/m3

5.325

3.550

6.2

W/Cementations ratio

0.42

0.42

0.361

Note:-

1. For exact W/C ratio the water in admixture should also be taken into account.

2. The W/C ratio of PPC and OPC is taken the same assuming that the strength properties of both are the same. If it is found that the PPC is giving the low strength then W/C ratio of PPC have to be reduce, which will increase the cement content. For getting early strength and in cold climate the W/C ratio of PPC shall also be required to be reduced.

3. PPC reduces 5% water demand. If this is found by trial then take reduce water for calculation.

4. If the trial mixes does not gives the required properties of the mix, it is then required to be altered accordingly. However, when the experiences grows with the particular set of materials and site conditions very few trials will be required, and a expert of such site very rarely will be required a 2nd trial.

5. It may be noted that, for the fly ash concrete the total cementation material is greater but the OP cement content is smaller, the coarse aggregate content is deliberately, the same, the water is reduced and the density is reduced, because of the lower density of fly ash compared with OPC.

CONCLUSION
1. For 4.5 N/mm2 flexural strength concrete having same material and requirement, but without water reducer, the PPC and OPC required will be 175/0.42 = 417kg/m3

2. With the use of superplasticizer the saving in cement is 62 kg/m3 and water 26 lit/m3 for PPC and OPC.

3. In the Fly ash concrete the saving in cement is 122 kg/m3 and water 33 lit/m3 including utilization of 98 kg/m3 of fly ash witch is a waste material.

4. In the financial year 2009-2010 India has produces 200 million tonnes of cement. In India one kg of cement produce emitted 0.93 kg of CO2. Thus the production of 200 million tonnes of cement had emitted 200 x 0.93 = 186 million tonnes of CO2 to the atmosphere.

5. If 50 million tonnes cement in making concrete uses water reducers 7500000 tonnes of cement can be saved. 3750000 KL of potable water will be saved and the saving of Rs. 3300 crores per year to the construction Industry. 6975000 tonnes of CO2 will be prevented to be emitted to the atmosphere. The benefits in the uses of water reducers not limited to this. When water reduces shrinkage and porosity of concrete are reduces which provides the durability to concrete structures.

6. India is facing serious air, water, soil, food and noise pollution problems. Every efforts therefore are necessary to prevent pollution on top priority basis.

7. As the stress induced in concrete pavements are mainly flexural, it is desirable that their design is based on the flexural strength of concrete. The quality of concrete is normally assessed by measuring its compressive strength. For pavings, however, it is the flexural strength rather than the compression strength of concrete which determine the degree of cracking and thus the performance of road, and it is imperative to control the quality on the basis of flexural strength.

REFERENCES:

1IS : 383-1970Specifications for coarse and fine aggregates from natural sources for concrete (second revision) BIS, New Delhi
2IS: 456-2000Code of practice for plain and reinforced concrete (fourth revision), BIS, New Delhi
3IS: 9103-1999Specification for admixtures for concrete (first revision) BIS, New Delhi
4IS: 8112-1989Specifications for 43 Grade ordinary portland cement (first revision) BIS, New Delhi
5IS: 2386 (Part-III) 1963method of test for aggregate for concrete. Specific gravity, density, voids, absorption and bulking, BIS, New Delhi
6IS: 3812 (Part-I) 2003Specification for pulverized fuel ash: Part-I for use as pozzolana in cement, cement mortar and concrete (second revision) BIS, New Delhi
7IS: 1489-Part-I 1991Specifications for portland pozzolana cement (Part-I) Flyash based. (Third revision), BIS, New Delhi
8IRC: 15-2002 – Standard specifications and code of practice for

construction of concrete road (third

revision)

9Kishore Kaushal, “Concrete Mix Design Based on Flexural Strength for Air-Entrained Concrete”, Proceeding of 13th Conference on our World in Concrete and Structures, 25-26, August, 1988, Singapore.
10Kishore Kaushal, “Method of Concrete Mix Design Based on Flexural Strength”, Proceeding of the International Conference on Road and Road Transport Problems ICORT, 12-15 December, 1988, New Delhi, pp. 296-305.
11Kishore Kaushal, “Mix Design Based on Flexural Strength of Air-Entrained Concrete”. The Indian Concrete Journal, February, 1989, pp. 93-97.
12Kishore Kaushal, “Concrete Mix Design Containing Chemical Admixtures”, Journal of the National Building Organization, April, 1990, pp. 1-12.
13Kishore Kaushal, “Concrete Mix Design for Road Bridges”, INDIAN HIGHWAYS, Vol. 19, No. 11, November, 1991, pp. 31-37
14Kishore Kaushal, “ Mix Design for Pumped Concrete”, Journal of Central Board of Irrigation and Power, Vol. 49, No.2, April, 1992, pp. 81-92
15Kishore Kaushal, “Concrete Mix Design with Fly Ash”, Indian Construction, January, 1995, pp. 16-17
16Kishore Kaushal, “High-Strength Concrete”, Bulletin of Indian Concrete Institute No. 51, April-June, 1995, pp. 29-31
17Kishore Kaushal, “Concrete Mix Design Simplified”, Indian Concrete Institute Bulletin No. 56, July-September, 1996, pp.
25-30.
18Kishore Kaushal, “Concrete Mix Design with Fly Ash & Superplasticizer”, ICI Bulletin No. 59, April-June 1997, pp. 29-30
19Kishore Kaushal. “Mix Design for Pumped Concrete”, CE & CR October, 2006, pp. 44-50.

Table. 1: Grading of Aggregates

IS Sieve Designation

Percentage Passing

Fine Aggregate

Crushed Aggregate

10 mm

20 mm

40 mm

100

20 mm

100

12.5 mm

100

10 mm

100

89

0

4.75 mm

98

6

2.36 mm

86

0

1.18 mm

71

600 Micron

40

300 Micron

21

150 Micron

5

2002 Designer By Jayco

Table. 2: Approximate free-water content (kg/m3) required to give various levels of workability for non-air-entrained (with normal entrapped air) concrete.

Maximum size of aggregate(mm)

Type of aggregate

Slump(mm)

15-45

10

Uncrushed Crushed185

215

20Uncrushed Crushed165

195

Note:- When coarse and fine aggregate of different types are used, the free water content is estimated by the expression.
2/3Wf+1/3Wc
Where,
Wf = Free water content appropriate to type of fine Aggregate
Wc = Free water content appropriate to type of coarse aggregate.

Table. 3: Proportion of fine aggregate (percent) with 10mm and 20mm maximum sizes of aggregates and slump 15-45 mm.

Grading Zone of F.A

W/C Ratio

10 mm aggregate

20 mm aggregate

I

0.3

47-57

37-45

0.4

49-59

39-47

0.5

51-61

41-49

II

0.3

39-48

30-37

0.4

41-50

32-39

0.5

43-52

34-41

III

0.3

32-38

25-30

0.4

34-40

27-32

0.5

36-42

29-34

IV

0.3

28-32

22-26

0.4

30-34

24-28

0.5

32-36

26-30

I am thankful to Sir Kaushal Kishore for publishing his research work here on engineeringcivil.com. I am sure, this research paper will help many civil engineers around the world in understanding how to do mix design for concrete roads as per IRC-15-2002.