STUDY ON CONCRETE WITH STUDY ON CONCRETE WITH STONE CRUSHER DUST STONE CRUSHER DUST AS FINE AGGREGATEAS FINE AGGREGATE

PRESENTATION BYRaghavendra. T

I Sem. M.Tech (Structural Engineering)Dept of Civil Engineering

BIT, Bangalore.

GUIDEDr. M. U. ASWATH

ProfessorDept of Civil Engineering

BIT, Bangalore.

1 1 INTRODUCTIONINTRODUCTION o Stone crusher dust, which is available

abundantly from crusher units at a low cost in many areas, provides a viable alternative for river sand in concrete.

o Investigations done by Giridhar Kumar. V, Master of Engineering (SE) degree, Osmania University, Hyderabad, on the use of stone crusher dust in concrete as an alternative to river sand are presented in this report.

o The tests conducted pertain to concrete with river sand of strength 28.1 MPa.

o Tests on the strengths of concrete, and on the flexural behaviour of RC beams under two-point loading were conducted.

o Failure loads and cracking patterns of the beams with sand and with crusher dust as fine aggregates were compared.

o The investigations indicate that stone crusher dust has a good potential as fine aggregate in concrete construction.

o Crusher does not only reduces the cost of construction buts also helps reduce the impact on the environment by consuming the material generally considered as a waste product with few applications.

DRY STONE DUST COLLECTORSDRY STONE DUST COLLECTORS

STONE DUST STONE DUST

STONE DUST USED FOR SOIL ENRICHMENTSTONE DUST USED FOR SOIL ENRICHMENT

Availability of material:Crusher dust from quarries and from

crusher units.

2 EXPERIMENTAL PROGRAMME

(By Giridhar Kumar. V) Standard concrete cubes (150 mm), cylinders

(150x300 mm), prisms (100x100x500 mm) as well as beams (120x150x1350 mm) were tested.

2.1 Properties of Various Materials tested2.1 Properties of Various Materials tested

Table1 Properties of fine aggregates

Property

Fine aggregate

River sand Crusher dust

Bulk density,kg/m3 1157.00 660.00

Specific gravity 2.27 2.6

Fineness modulus 2.74 2.71

Free surface moisture

0.10 % 0.60 %

Water absorption 1.0 % 0.9 %

Table2 Properties of the coarse aggregate

Properties Value

Maximum normal sizes, mm 20

Bulk density, kg/m3

Loose state

Compacted state

1450

1530

Specific gravity 2.78

Fineness modulus 6.85

Voids, percent

Loose state

Compacted state

41

47

Free surface moisture, % 0.6

water absorption, % 0.5

2.1.1 Physical properties

The physical properties of the fine and coarse aggregates used are indicated in Tables1 and 2

Ordinary portland cement (OPC) Grade 53 cement (strength of standard mortar cubes = 55.6 MPa with 28 percent normal consistency) conforming to IS 12

269 : 1987 was used in the test specimen

Table3 Concrete mix proportions

MaterialMixture

A(1 : 1.4 : 3.5 )

B( 1 : 1.6 : 3.5 )

Cement. Kg/m3 360.0 360.0

River sand. Kg/m3 504.0 -

Coarse aggregate. Kg/m3

1 260.0 1 260.0

Water/cement ratio

0.54 0.53

Slump mm 28 25

Compaction factor 0.92 0.87

Table4 Compressive Strength of 150 mm Cubes (average of 3 cubes)

Mix

Fine aggregate

Compressive strength, N/mm2

Percentage increase

3day 7day 28day 3day 7day 28day

A Sand 15.0 18.9 28.1 - - -

B Crusher

dust

18.8 23.0 32.8 25.3 21.7 16.8

Mix Fine aggregate

Tensile strength Percentage increase

7 day 28 day 7 day 28 day

A Sand 2.27 2.72 - -

B Crusher dust 2.76 2.9 21.6 6.6

Table5 Split tensile strength of 150 x 300 mm cylinders (average of 3 prisms)

Table6 Flexural tensile strength of 100 x 100 x 500 prisms (average of 3 prisms)

3 VARIOUS TESTS AND DISCUSSIONS3.1 Tests on Plain Concrete

Standard cubes, prisms and cylinders were tested for compressive and tensile strength properties. The specimens were tested after 3,7 and 28 days of curing and the mean strength values of three specimen were compared .

Mix Fine aggregate

Tensile strength

(N/mm2)

Percentage increase

7 day 28 day 7 day 28 day

A Sand 2.85 3.7 - -

B Crusher dust 3.72 4.45 30.5 20.3

The results of the tests on 150 mm-cubes are indicated in Table 4. the 28-day compressive strength was 28.1 MPa for Mix A (concrete with river sand) and 32.8 MPa for Mix B (concrete with stone crusher dust); the strength of Mix B was about 17 percent higher than that of Mix A, the 3 and7 days strengths have shown similar trends.

Table5 indicates the results of split tensile strength tests on 150 x 300 mm cylinders. Mix A showed a 28-day mean value of 2.72 MPa, while Mix B developed a mean strength of 2.90 MPa, an increase of about 7 percent.

The flexural strength test results on 100 x 100 x 500 mm prisms (modulus of rupture) are shown in Table6. the flexural strength of Mix A was found to be 3.70 MPa, while that of Mix B was 4.45 MPa at 28-days, an increase of about 20 percent.

3.2 Test on RC Beams

The beams cast with sand as fine aggregate were designated SU 1, SU 2 and SU 3 (SU series) while those with crusher dust as fine aggregate were designated CDU 1, CDU 2 and CDU 3 (CDU series). The concrete was compacted using a 25 mm needle vibrator; moulds were removed after 24 hours, and the specimens cured for 28 days before testing

Table7 Beam deflections at 60.0 KN load

Sl no Beam

Deflection, mm

1/3 span Mean value

Mid-span Mean value

1 Su1 12.99 14.62

2 Su2 9.72 11.3

3 Su3 12.12 11.61 14.05 13.32

4 Cdu1 13.6 14.28

5 Cdu2 10.10 11.16

6 Cdu3 9.45 11.05 10.4 11.95

3.3 Strains

The beams with crusher dust developed smaller strains generally, the difference up to a load of 30.0 kN was about 20 percent. However, the strains in the beams with crusher dust increased suddenly at load beyond 50.0 kN at one-third span sections, possibly due to crushing of the concrete at the loaded section

3.4 Crack Widths the beams with crusher dust generally indicated

fewer cracks of smaller width than the beams with river sand.

Table9 Maximum and average crack widths of the test beams

SL NO BEAM CRACK WIDTH, MM

MAX MEAN

1 Su1 1.5 0.17

2 Su2 1.55 0.29

3 Su3 2.05 0.52

4 Cdu1 2.01 0.24

5 Cdu2 1.55 0.25

6 cdu3 0.5 0.15

The maximum and mean widths of cracks for the beams of SU series worked out to be 1.70 mm and 0.33 mm, respectively. The corresponding values for the beams of CDU series were 1.38 mm and 0.21 mm. It can be noted that the beams with crusher dust developed cracks of smaller widths as well as fewer in number of cracks.

Table10 Cost of M20 grade concrete mixes

Mix

Fine Aggregate Description

Quantity Rate per m3

Cost

m3 Rs. Rs.

A River sand Cement 0.266 6600.00 1755.60

Sand 0.436 1250.00 545.00

Coarse agg.

0.868 848.00 736.06

total 3036.66

B Crusher dust

Cement 0.266 6600.00 1755.60

Crusher dust

0.347 115.00 39.91

Coarse agg.

0.868 848.00 736.06

total 2531.57

4 CONCLUSIONS4 CONCLUSIONS

It can be seen that stone crusher dust as fine aggregate has in general no detrimental effect on the strength and performance of concrete when designed correctly.

• The concrete cubes with crusher dust developed about 17 percent higher strength in compression, 7 percent more split tensile strength and 20 percent more flexural strength (modulus of rupture) than the concrete cubes/beams with river sand as fine aggregate. The differences in strengths are possibly due to the sharp edges of stone dust providing stronger bond with cement compared to the rounded shape of river sand.

Similarly, the RC beams with crusher dust sustained about 6 percent more load under two point loading, and developed smaller deflections and smaller strains than the beams with river sand. The cracks were also fewer, and the crack widths were smaller. The better performance of the beams with stone dust may be due to the higher strength of concrete.

Based on the test results presented by

Giridhar Kumar. V , it can be concluded that crusher stone dust can be adopted as fine aggregates in concrete structures.

4 CONCLUSIONS (Contd...)4 CONCLUSIONS (Contd...)

REFERENCESREFERENCES

GIRIDHAR KUMAR. V, Strength characteristics of concrete with crusher dust as fine aggregate, Dissertation submitted in partial fulfillment of the requirements of the Master of Engineering (SE) degree, Osmania University, Hyderabad, 2003.

PRABIN PAUL. K, SOUMYA SAIRA JOY, AMITA ABRAHAM, SMITHA. K, KURIACHAN SIMON & NAVEEN. J

“An alternative to natural sand” Project report submitted in partial fulfillment for the award of the B. Tech. degree in Civil Engineering, under the guidance of Mrs. Molly John , Asst Professor, Department of Civil Engineering, M. A. College of Engineering, Mahatma Gandhi University, Kerala, 2003.

BIBLIOGRAPHYBIBLIOGRAPHY

MISHRA, V. N, Use of stone dust from crushers in cement-sand mortars. The Indian Concrete journal, August 1984, Vol 58, Nos 58,No,pp.219-223.

BABU, K. K. RADHAKRISHNA,R. and NAMBIAR, E.K.K. Compressive strength and Construction review, September 1997, vol 10,No 9,pp 25-29.

SAHU, A.K.,KUMAR, SUNIL and SACHAN, A.K.Crushed stone waste as fine aggregate for concrete, The Indian concrete Journal, January 2003, Vol 77,N0 1, pp.845-847.

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