Ceraplast and Ceraproof Admixtures Behaviour on High Strength Concrete

Ceraplast and Ceraproof Admixtures Behaviour on High Strength Concrete

B. Vamsi Krishna1, S M Abdul Mannan Hussain2, V. Ranjith Kumar3

Civil Engineering Department, Malla Reddy Engineering College (Autonomous) Hyderabad, India.

Abstract In this paper, a brief practical review is presented on two grades of concrete of which one is medium strength concrete(M40)and the other is high strength concrete(M60), containing some mineral and chemical admixtures by mass of the cementitious material. The behavior of specimens cast with medium strength concrete and high strength concrete with and without admixtures are compared with respect to ultimate strength, workability and cracking. Strength improving admixtures such as CERAPLAST-400, CERAPROOF-PXL are applied for concrete mix to develop strength.

KeywordsHigh strength concrete, Admixtures, Rice husk ash, Super plactizers,

1. INTRODUCTION

   Engineers, Architects and Designers all over the world, have been considering from time to time the use of higher strength concrete in their structures.

   The objective of this report is to review the effects of admixtures on concrete properties and provide some guidelines for adopting appropriate concrete admixtures for improving strength. Since strength development concrete is a broad topic, this report only highlights the admixtures to be included in concrete for improving strength. These structures include not only high raised buildings but also dams, bridges. As the admixtures enhance concrete properties in terms of strength, durability and workability, the end product is also suitable for structures exposed to aggressive environments. Strength improving admixtures such as CERAPLAST-400, CERAPROOF-PXL, and RICE HUSK ASH. are applied for concrete mix

2. NEED OF HIGH STRENGTH CONCRETE

   To put the concrete in to service at much earlier age for example opening the pavement at 3-days.

   To build high-rise buildings by reducing column sizes and increasing available space.

   To build the superstructures of long-span bridges and to enhance the durability of bridge decks.

3. DESIGN OF HIGH-STRENGTH CONCRETE MIX

   Optimum concrete mix design results from selecting locally available materials that make the fresh concrete placeable and finishable and that ensure the strength development and other desired properties of hardened concrete as specified by the

   designer. Some of the basic concepts that need to be understood for high strength concrete are:

   Aggregates should be strong and durable. They need not necessarily be hard and of high strength but need to be compatible, in terms of stiffness and strength, with the cement paste. Generally smaller maximum size coarse aggregate is used for higher strength concretes. The sand may have to be coarser than that permitted by ASTM C 33 (fineness modulus greater that 3.2) because of the high fines content from the cementitious materials.

   High strength concrete mixtures will have a high cementitious materials content that increases the heat hydration and possibly higher shrinkage leading to the potential for cracking. Most mixtures contain one or more supplementary cementitious materials such as fly ash (class c or f), ground granulated blast furnace slag, silica fume, metakaolin or natural pozzolanic materials

   High strength concrete mixtures generally need to have a low water-cementitious materials ratio (w/c). W/c ratios can be in the range of 0.23 to 0.35. These low w/c ratios are only attainable with quite large dosage of high range water reducing admixtures (or super plasticizers) conforming to Type F or G by ASTM C 494. A Type A water reducer may be used in combination

   The total cementitious material content will be typically around 415 kg/m3 but not more than about 650 kg/m3.

   The use of air entrainment in high strength concrete will greatly reduce the strength potential.

4. SALIENT FEATURES OF HIGH STRENGTH

   CONCRETE

   • Compressive strength > 50 MPa, even up to 80 MPa

   • Water-binder ratio = 0.25-0.35, therefore very little free water.

   • Reduced flocculation of cement grains.

   • Wide range of grain sizes.

   • Densified cement paste.

   • No bleeding homogeneous mix.

   • Less capillary porosity.

   • Discontinuous pores.

   • Stronger transition zone at the interface between cement paste and aggregates.

   • Low free lime content.

   • Endogenous shrinkage.

   • Powerful confinement of aggregates.

   • Little micro-cracking until about 65-70% of fck.

   • Smooth fracture surface.

5. TESTING OF MATERIALS

   In the present investigation the following materials were used.

   • Zuari 43 grade cement conforming to IS: 12269 – 1987

   • Fine aggregate and coarse aggregate conforming to IS: 383 – 1970

     Admixtures :

   • High performance Super plasticizing Admixture CERAPLAST 400 Conforming to IS: 9103 1999.

   • Fly Ash Hydration Promoter CERAPROOFPXL Conforming to IS: 9103 1999.

     6.1. High Performancesuper Plasticizing Admixture Ceraplast 400.

   • Ceraplast 400 is a high performance, low dosage super plasticizer based on Melamine Formoddedlyde Sulphorate (MFS). Highly recommended for increased early strength of concrete, which is a must for precast and prestressed concrete industries.

   • Ceraplast 400 disperses cement particles more rapidly in the concrete mix

   • Ceraplast 400 is very advantageous for pre-cast concrete constructions and for concrete sleepers, electric poles and for pre-stressed concrete constructions.

   • Ceraplast 400 increases durability of concrete structures Ceraplast 400 is a high performance, low dosage super plasticizer based on Melamine Formoddedlyde Sulphorate (MFS). Highly recommended for increased early strength of concrete, which is a must for precast and prestressed concrete industries.

   • Ceraplast 400 disperses cement particles more rapidly in the concrete mix

   • Ceraplast 400 is very advantageous for pre-cast concrete constructions and for concrete sleepers, electric poles and for pre-stressed concrete constructions.

   • Ceraplast 400 increases durability of concrete structures (in parentheses). An exception would be the use of English units as identifiers in trade, such as 3.5-inch disk drive.

     • Ceraplast 400 when incorporated into the concrete improves the workability of the concrete without air

   entrainment due to its excellent dispersion characteristics.

   1. Method Of Use:

      Ceraplast 400 is directly added into the mix at the same time as the gauging water. Reduce water dosages for required consistency.

   2. Compressive Strength:

      Substantial reduction in the water content i.e. 20% – 25% can result in high early compressive strength for a constant slump. The ultimate compressive strength can be enhanced by upto 25% by proper mix design with ceraplast 400.

   3. Properties:

      Supply form : liquid

      Color : Transparent

      Specific gravity : 1.1 + 0.03

      Chloride contents : Nil

   4. Recommended Dosage:

   0.3% to 1.2% ceraplast 400 by weight of cement. Maximum dosage may have to be increased to as high as 2% of cement weight where exceptionally high strength is required. Suitable modifications in the mix design are required in such cases.

   6.1. Fly Ash Hydration Promoter Craproof Pxl

   Ceraproof PXL is a composite chemical based entirely on inorganic complex compound which accelerates dissolution of glassy phase of both low calcium and high calcium fly ash in solution to react with lime to generate secondary calcium silicate hydrate crystals for development of early strength in pozzolona blended cementitious binders.

   Ceraproof PXL can be used economically by the replacement of 70% cement. It is used for the production of high strength PPC concrete and mortar.

   1. PROPERTIES:

      Supply form : Powder

      Color : Off White

      Chloride contents : Nil

   2. recommended dosage:

      1 to 5% on weight of fly ash. Actual dose is to be determined by trail.

      The Mineral admixtures which we used in this present project

   3. Mix Design For Present Investigation

   In the present work the above method has been used to get proportions for high strength concrete.

   The concrete mix design for M40 and M60 were carried out according to Indian standard recommendation method IS 10262 1982. The calculations are given in Appendix A1 and A2. The proportions are given in Table.1

   Table.1 Mix Proportions

   60

   compressive strength (Mpa)

   50

   40

   30

   20

   10

   0

   M40 C.P 400 (W/C=0.32)

   7 days

   28 days

   C.P 400

   (W/C = 0.28)

   S.NO	Targeted strength (MPa)	Mix Proportions
   1	40	1:0.73:2.24:0.32
   2	60	1:0.51:1.61:0.25

6. TEST RESULTS AND DISCUSSIONS

   6.1. Compressive Strength Prediction:

   Compression test is the most common test conducted on hardened concrete, partly because it is an easy test to perform, and partly because most of the desirable characteristic properties of concrete are qualitatively related to its compressive strength.

   The cube specimen is of the size 15 x 15 x 15 cm. If the largest nominal size of the aggregates does not exceed 20mm, 10cm size cubes may also be used as an alternative. The characteristic compressive strength varies for both medium strength concrete and high strength concrete.

   TABLE.2 DATA RECORDED FOR CERAPLAST- 400 DURING THE TEST

   Bar Chart: 1 comparison of compressive strength vs water cement ratio of CERAPLAST- 400 for M40

   7 days

   28 days

   80

   compressive strength (Mpa)

   70

   60

   50

   40

   30

   20

   10

   0

   M60 C.P 400 (W/C=0.25)

   7 days

   28 days

   S.NO	Grade of concrete	Workability(Com paction factor )	Compressive strength of 7 days(MPa)	Compressive strength of 28 days(MPa)
   1	M-40	0.94	39	44
   2	M-40+CERAPLAST 400( W/C = 0.32 )	0.98	33	49
   3	M-40+CERAPLAST 400( W/C = 0.28 )	0.96	41	55
   4	M-60	0.9	48	64
   5	M-60+CERAPLAST 400	<0.9	52	68

   Bar Chart: 2 comparison of compressive strength vs water cement ratio of CERAPLAST- 400 for M60

   60

   compressive strength (Mpa)

   50

   40

   30

   20

   10

   0

   M40 C.P 400 (W/C=0.32)

   C.P 400

   (W/C = 0.28)

   Compressive strength vs w/c ratios

   CERAPLAST- 400 with M40

   7 days

   28 days

   80

   Compression strength (Mpa)

   70

   60

   50

   40

   30

   20

   10

   0

   M60 C.P 400 (W/C=0.25)

   60

   compressive strength (Mpa)

   50

   40

   30

   20

   10

   0

   M40 C.P PXL 5% (W/C=0.32)

   7 days

   28 days

   C.P PXL 5%+ C.P 400 (W/C = 0.32)

   Compressive strength vs w/c ratios

   CERAPLAST- 400 with M60

   TABLE.3 DATA RECORDED FOR CERAPROOF- PXL

   DURING THE TEST

   S.NO	Grade of concrete	Workability(Com paction factor )	Compressive strength of 7 days(MPa)	Compressive strength of 28 days(MPa)
   1	M-40	0.94	39	44
   2	M-40+CERAPROOF PXL( W/C = 0.32 )	0.85	35	46
   3	M-40+CERAPROOF PXL( W/C = 0.28 )	0.89	36	49

   Compressive strength vs w/c ratios (CERAPLAST- PXL with M40)

   7 days

   28 days

   60

   50

   Compressive strength (Mpa)

   40

   30

   20

   10

   0

   M40 C.P 400

   C.P 400

   C.P PXL 5% C.P PXL 5% R.H.A 10% R.H.A 10%

   7 days

   28 days

   (w/c=0.32)

   (w/c= 0.28)

   + C.P 400

   + C.P 400

   ( Chemical Admixtures) ( Mineral Admixtures )

   60 Bar Chart: 4 Represents the combination of both chemical

   and mineral admixtures

   compressive strength (Mpa)

   50 60

   40

   50

   Compressive strength (Mpa)

   30

   40

   20

   10 30

   7 days

   28 days

   0

   M40 C.P PXL 5% (W/C=0.32)

   20

   C.P PXL 5%+ C.P

   400 (W/C = 0.32) 10

   Bar Chart: 3 Comparison of compressive strength vs water cement ratio of CERAPROOF- PXL

   0

   M40 C.P 400

   C.P 400

   1. PXL 5% C.P PXL 5% R.H.A 10% R.H.A 10%

      (w/c=0.32)

      (w/c= 0.28)

      + C.P 400

      + C.P 400

      ( Chemical Admixtures) ( Mineral Admixtures )

      Compressive strength vs w/c ratios for the combination of chemical and mineral admixtures

7. CONCLUSIONS

   • The present paper mainly predicts the medium strength concrete can be safely extended to high strength concrete by adding mineral and chemical admixtures.

   • From the present investigation it is observed that the experimental characteristic compressive strength of the cubes is nearly 15% to 20% more, than the medium and high strength concrete cube compressive strength.

   • By comparing all the mineral and chemical admixtures which were used in this test, CERAPLAST 400 attains a maximum characteristic compressive strength of 55 MPa for 28 days.

8. SUGGESTIONS FOR FUTURE WORK

• The CERAPLAST 400 (i.e. super plasticizer) can be replaced with hyper super plasticizer which is a water reducer and high strength chemical admixture in market.

• The same investigation can be carried out for different water cement ratios for each chemical and mineral admixture.

• For getting of more strength we can go for the combination of both chemical and mineral admixtures in the desirable dosages. Then the project will be an economical one.

REFERENCES

1. Concrete Technology by M.S SHETTY.

2. International Symposium on INNOVATIVE WORLD OF CONCRETE Vol-II, IWC-98 proceedings.

3. High Performance Concrete: Properties and Applications-by SP SHAH & SH AHMAD.

4. The Indian Concrete Journal, Vol.80, June 2006.

5. Admixture for Concrete: Improvement of properties E. Vazquez, Chapman & Hall.

6. High Performance Concrete V. M. Malhotra.

7. KRISHNARAJU, N., Design of Concrete Mixes, CBS publications, New Delhi, 1974.

8. SRINIVASA RAO, P., Problems in Quality Assurance And Quality Control Of igh Strength Concretes, National Seminar On High Strength Structural Concrete, Bangalore, Dec. 5th & 6th, 1991, I.109- 117.

9. TOMOSAWA, F., MASADA, M. ABE, A.SHIMIZU, AND NAKANE, S., High Strength Concretes For High-Rise Buildings In Japan, High Strength Concrete Structure, Second International Symposium, SP-121, ACI, 1990, PP.33-45.

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