A PROJECT ON BY- Swapnil Dixit.

SR. NO. CHAPTER 1INTRODUCTION 2 MATERIALS AND THEIR TESTING 3 CONCRETE AND ITS TESTING 4 EXPERIMENTAL STUDY 5RESULTS 6CONCLUSION APPENDIX REFERENCES INDEX

 CONCRETE: - 1) Versatile material, recycle able and environmental-friendly material. 2) Its per capita consumption, least energy consumption, ability to absorb vast proportions of waste products.  HARDENED CONCRETE: - 1) Chemical action between cement and water. 2) A compact mass like an artificial stone. 3) Strength depends on properties of ingredients and level of controls on site.

 CHARACTERISTICS OF GOOD CONCRETE: -  Performance in green and plastic state.  Compressive strength: Index of overall quality.  Grades of concrete and their strength.  Strong, durable, impermeable concrete with minimum dimensional changes.  COMPOSITE CONCRETE: -  Large compressive strength and low tensile strength.  Less resistance to tensile stresses, causes lack of ductility, poor fracture, toughness and propagation of cracks.  Composite concrete: Addition of steel fibers.  Different tests on concrete in the experiment.

MATERIALS AND THEIR TESTING  CEMENT: - Physical properties of cement: - FINENESS TEST: - 1)By sieving 2) By blain air permeability apparatus  Sieve test: - 1) IS sieve no. 9 2) Weight of residue left after sieving decides fineness. 3) Wt. shouldn’t exceed 10% for ordinary cement.  Standard consistency: - A Vicat plunger having 10mm diameter and 50mm length to penetrate at the depth of 33-35mm from the top of the mould. 

 Setting time: - 1)Initial setting time should not be less than 30 minutes. 2) Final setting time should not be more than 10 hours.

 Compressive strength: -  The compressive strength of hardened cement is the most important of all the properties.  Strength of cement is indirectly found on cement sand mortar in specific proportion. The standard sand is used for finding the strength of cement.  Aggregate: - The aggregate passing through IS 4.75 mm sieve is called as fine aggregate. The most physical properties are- 1) fineness modulus 2) Specific gravity 3) Water absorption 4) Bulking  Coarse aggregate: - The aggregate retained on IS 4.75 mm sieve is called as coarse aggregate.

 Elongation Index: -  The elongation index on an aggregate is the percentage by weight of particles whose greatest dimension is greater than 1.8 times their mean dimension.  The elongation index is not applicable to sizes smaller than 6.3 mm.  This test is conducted by using metal length gauge.  The elongation index is the total weight of material retained on the various length gauges expressed as a percentage of the total weight of the sample gauged.  Bulk Density: -  Bulk density is weight of material in a given volume.  It is normally expressed in Kg per liter.  A cylindrical measure preferably machined to accurate internal dimension is used for measuring bulk density.

 The bulk density depends on the particle size distribution and shape of the particles.  The higher the bulk density, the lower is the void content to be filled by sand and cement.  Specific gravity: -  The specific gravity of an aggregate is defined as the ratio of the mass of solid in a given volume of sample to the mass of an equal volume of water at the same temperature.  Higher the specific gravity of an aggregate, concrete will be harder and stronger. The specific gravity is given by : specific gravity = c / (a-b)

 The water absorption of aggregate is determined by measuring the increase in weight of an oven dry sample when immersed in water for 24 hours.  The ratio of the increase in weight to the weight of the dry sample expressed as percentage is known as water absorption of an aggregate.  The rate and amount of absorption within a time interval equal to the final set of the cement will only be a significant factor rather than the 24 hours absorption of aggregate.

 The surface moisture expressed as a percentage of the weight of the saturated surface dry aggregate is termed as moisture content.  The determination of moisture content of an aggregate is necessary in order to determine the net water cement ratio for a batch of concrete.  High moisture content will increase the effective water cement ratio to an appreciable extent and may make concrete weak unless a suitable allowance is made.

 The aggregate crushing value gives a relative measure of the resistance of an aggregate to crushing under a gradually applied compressive load.  This test is made on single size aggregate passing 12.5 mm and retained on 10 mm sieve.  The crushing value of aggregate is restricted to 30 % for concrete used for roads and pavements and 45 % may be permitted to other structure.

 The aggregate impact value gives relative measure of the resistance of an aggregate to sudden shock or impact.  The ratio of the weight of fines formed, to the weight of the total sample taken is expressed as percentage. This is known as aggregate impact value.  IS specifies that aggregate impact value shall not exceed 45 % by weight for aggregate used for concrete other than wearing surface and 30 % by weight, for concrete wearing surfaces.

 Water is an important ingredient of concrete as it actively participates in the chemical reaction with cement.  The quality of water affects the strength, it is necessary to take into account the purity and quality of water.  The best course to find out whether a particular source of water is suitable for concrete making or not, is to make concrete with this water and compare its 7 days and 28 days strength with companion cubes made with distilled water.

 To improve the tensile strength of concrete in some amount, fibers are added to the concrete.  The aspect ratio of the fiber is the ratio of its length to its diameter. Typical aspect ratio ranges from 30 to 150.  Some of the fibers that could be used are steel fibers, polypropylene, nylons, asbestos, coir, glass and carbon.  Steel fiber is the most commonly used fibers.  Uses of steel fibers make significant improvements in flexural, impact and fatigue strength of concrete.

 uses of superplasticizers permit the reduction of water to the extent up to 30 % without reducing workability in contrast to the possible reduction up to 15 % in case of plasticizers.  The use of superplasticizers is practiced for production of flowing, self leveling, self compacting and for the production of high strength and high performance concrete.  The superplasticizers are more powerful as dispersing agents and they are high range water reducers.  superplasticizers also produce a homogeneous, cohesive concrete generally without any tendency for segregation and bleeding.

Indian standard recommended method A)Target mean strength for the mix design : - The target mean compressive strength (ƒck) ƒck = ƒck + tS The objectives of mix design are : -  To achieve the stipulated minimum strength and durability.  To make the concrete in the most economical manner.  To know the workability of concrete for different proportions. Methods of Mix Design  ACI Committee 211 method  IRC 44 method  Rode Note No. 4 method  DOE method  British method  Indian standard recommended method – IS

C) Estimation of entrapped air : -  The air content is estimated from table 3.1 for the normal maximum size of aggregate used. Table 3.1 – Estimated air content Maximum size of aggregate (mm) Entrapped air, as % volume of concrete B) Selection of water / cement ratio : -

Table 3.2 Approximate sand and water contents per cubic meter of concrete W/C = 0.60, Workability = 0.80 C.F. (slump 30mm approximate) (Application for concrete up to grade M 35 ) Maximum size of aggregate (mm) Water content including surface water, per cubic meter of concrete (kg) Sand as percent of total aggregate by absolute volume D) Selection of water content and fine to total aggregate ratio : -

Change in conditions stipulated for tables Adjustment required in Water content % sand in total aggregate For sand conforming to grading Zone І, Zone ІІІ or Zone Іν of table 4, IS % for Zone І -1.5 % for Zone ІІІ - 3 % for Zone Іν Increase or decrease in the value of compacting factor by 0.1 ± 3 % 0 Each 0.05 increase or decrease in water – cement ratio 0 ± 1 % For rounded aggregate - 15 kg - 7 % Table 3.3 Adjustment of values in water content and sand percentage for other conditions E) Calculation of cement content : - Cement by mass = water content / water cement ratio

G) Actual quantities required for mix : - Assume that aggregates are saturated and surface dry. H) The calculated mix proportion : - It is calculated as per IS

Workability : - Workability : - There are various factors affecting workability as – Water content, Mix proportion, Size of aggregate, Shape of aggregate, Surface texture of aggregate, Grading of aggregate, Use of admixtures. Tests on Fresh Concrete  To ascertain the quality of concrete following tests are required to be performed on fresh concrete.

Measurement of workability (1199 – 1959) : - The following tests are commonly employed to measure the workability –  Slump test  Compaction factor test  Flow test  Kelly ball test  Vee Bee consistometer test Slump test : - Fig. 3.1 Standard Mould for Slump Cone test

Compaction factor test : - The Compacting Factor = weight of partially compacted concrete / Weight of fully compacted concrete Fig. 3.2 Compaction Factor Apparatus Vee Bee Consistometer : - Vee Bee Consistometer : - It measures indirectly workability of Concrete. This test consist of vibrating table, a metal pot, a sheet cone, a standard iron rod. This method is very suitable for dry concrete.

Flexure test : -  In case of symmetrical two point loading, critical crack may appear at any section, not strong enough to resist the stress within the middle third, where the bending moment is maximum.  The modulus of rupture is determined from the moment at failure as f r = M / Z. Fig. 3.3 Standard Set up for Flexural test

Fig. 3.4 Rebound Hammer e) Type of coarse aggregate. f) Type of cement. g) Type of mould. h) Carbonation of concrete surface. Ultrasonic pulse velocity : -  Ultrasonic pulse velocity method consists of measuring the time of travel of an ultrasonic pulse, passing through the concrete to be tested.

Fig. 3.5 Ultra sonic pulse velocity equipment Fig. 3.6 Methods of measuring Pulse Velocity

EXPERIMENTAL STUDY INTRODUCTION The concrete material ingredients are tested as per the procedures stated in respective IS codes. Cement Ordinary Portland Cement Birla Super of 53 grade confirming to IS was used. The physical properties are tabulated in table

37 Mpa49.2 Mpa7 days compressive strength 10 max0.9 mm Soundness 600 max244 min Final setting time 30 min164 min Initial setting time 30.50% Normal Consistency 225 min297 Fineness m 2 / kg 3.10 Specific Gravity IS specifications Value Property

The manufactured sand procured from local stone crusher was used as fine aggregate while the nominal size 25 mm (A1) and 12.5mm (A2) aggregates were used as coarse aggregate Sieve analysis The standard sieves are arranged in the sequence and sieve analysis is done. The results of sieve analysis of fine aggregate are shown in table 4.2 and of coarse aggregates are shown in table 4.3 and table 4.4.

< % Passing% Cumulative weight retained Cumulative weight retained Weight retained Sieve size Fineness modulus = 301 / 100 = 3.01

Sieve size Weight retained Cumulative weight retained % Cumulative weight retained % Passing <  Fineness modulus = / 100 = 7.57

----< % Passing% Cumulative weight retained Cumulative weight retained Weight retained Sieve size Fineness modulus = / 100 = 6.13

A. Fine aggregate Bulk density (loose) = / 3 = Kg / m3 Bulk density (compact) = / 3 = Kg / m3 B. Coarse aggregate (A1) Bulk density (loose) = / 15= Kg / m3 Bulk density (compact) = / 15 = Kg / m3 C. Coarse aggregate (A2) Bulk density (loose) = / 15 = Kg / m3 Bulk density (compact) = / 15 = Kg / m3

The specific gravity is given by: Specific Gravity = c / (a – b) Where, a = Mass of saturated surface dry aggregate in air b = Mass of saturated aggregate in water c = Mass of oven dry aggregate in air. A. Fine aggregate a = gm, b = 987 gm, c = gm Specific gravity = 1549 / ( ) = 2.65 % Water absorption = 100 x ( / 1549) = 1.50% B. Coarse aggregate (A1) a = gm, b = gm, c = gm Specific gravity = 1418 / ( ) = % Water absorption = 100 x ( / 1418) = 1.55%

Using the above physical properties of ingredient materials of concrete, mix design is prepared for M20 grade by IS code method A) Design stipulations 1) Characteristic compressive strength required in the field at 28 days =20 MPa 2) Maximum size of aggregate =25mm 3) Degree of workability =0.80 compaction factor 4) Degree of quality control =Good 5) Type of exposure =Mild. B) Test data for material 1) Specific gravity of cement = ) Compressive strength of cement at 7days = 49.2 Mpa. 3) a) Specific gravity of coarse aggregates = 2.82 b) Specific gravity of fine aggregates = ) Water absorption: a) Coarse aggregates = 1.30% b) Fine aggregates = 1.50%

-2.00For decrease in water cement ratio by 0.10 Sand in total aggregate Water content % adjustment required Change in condition

Trial Trial Design CA – A2CA – A1SandCementWaterMix No

For accurate quantities of constituent materials Electronic balance is used for weighing. Materials are mixed in concrete mixer initially in dry state. First 90% water is added and fibers are added manually. Then 10% water is mixed with superplasticizers in quantity 4ml per Kg of cement and is spread in mixer. The crimpled Fibers used having, C/S area = 2.6mm Χ 0.55mm Length = 40mm Diameter = 1.35mm Aspect ratio = 30 Concrete is placed in steel specimen & externally compacted on vibrating table After 24 hours, specimens were demoulded.

3-Beam 3-Cylinder 33Cubes 28 Day7 DaySpecimen

Photo – Preparing the Concrete Mix Photo – Dispersing the fibers in the concrete mix Photo – Concrete Mix with fibers

Photo – Concrete moulds on vibrating table for compaction Photo - Concrete cubes after 28 days curing

RESULTSIntroduction  Different concrete mixes were prepared with fiber volume percentage as 0.00%, 0.25%, 0.50%, 0.75% and 1.00%.  Workability tests were performed on fresh concrete.  Strength tests were performed on hardened concrete on 7 and 28 days curing.  The non destructive tests were also performed at 28 days curing.

Identification Mark Percentage volume of fibers M 20 – M 20 – M 20 – M 20 – M 20 – Mix Identifications Basic mix was M20 and identification marks were given as –

Identification No. M 20 – 0.00 M 20 – 0.25 M 20 – 0.50 M 20 – 0.75 M 20 – 1.00 Slump value (mm) Compaction factor Vee Bee time (sec) days Comp. stress MPa days Comp stress MPa Split tensile stress MPa Flexural tensile stress MPa Stress by rebound hammer MPa Ultra sonic pulse velocity (m / sec) Test Results

Photo - Cube and cylinder in compression testing machine Photo - Cylinder after split tensile test (a) Plain concrete (b) Concrete with fibers

Photo - Beam under Flexural testing (Concrete without fibers) Photo - Beam under Flexural testing (Concrete with fibers) Photo - Beam after Flexural tests (Concrete with fibers) Photo - Flexural testing of Beam (Concrete with fibers)

Photo - Rebound Hammer Test on cube specimen Photo - Ultrasonic Pulse velocity test on cube specimen

Applications It is applicable for following structures : - 1)Concrete Road Pavements 2)Runways 3)Tunnel Lining 4)Precast Units 5)Deck Slab 6)Blast and Impact Resistant Structures 7)Earthquake Resistant Structures etc.

The percentage increase is as follows –

Identification No. M 20 – 0.00 M 20 – 0.25 M 20 – 0.50 M 20 – 0.75 M 20 – 1.00 Compressive stress Split tensile stress Flexural tensile stress ) The failure pattern of fibrous concrete shows its suitability for blast and impact resistant structures and also seismic structures. 6) The control concrete beams fail suddenly and loose the load carrying capacity. Under loading it break in two pieces. 7) The concrete beams with fibers in varying proportions carry the load even after cracking and go under large deformation without breaking. 8) The presence of fibers changes the brittle failure in shear to ductile failure

9) M. A. Tantary, A. Upadhyay & J. Prasad, Design aid for shear strength of steel fiber based concrete, The Indian Concrete Journal, Jan. 2007, Vol-81, No. 1, pp ) Dr. K. B. Prakash, K. Ravi, Nataraj K. C., Characteristic properties of hybrid reinforced concrete produced with fibers of different aspect ratios, Civil Engineering & Construction Review, Dec. 2006, Vol. 19, No. 12, pp )______ Code Of Practice for Plain & Reinforced Concrete, IS 456 : 2000, Bureau of Indian Standards, New Delhi. 12) ______ Recommended Guidelines for concrete mix Design, IS : 1982, Bureau of Indian Standards, New Delhi. 13) ______ Specification for 53 Grade ordinary Portland cement, IS : 1987, Bureau of Indian Standards, New Delhi. 14) ______ Methods of tests for aggregates for concrete, IS 2386 (part 3 and part 4): 1963, Bureau of Indian Standards, New Delhi. 15) ______ Methods of sampling and analysis of concrete, IS 1199 : 1959, Bureau of Indian Standards, New Delhi. 16) ______ Non Destructive testing of concrete, IS (PART1 & 2) : 1992, Bureau of Indian Standards, New Delhi.

17) ______ Specification for coarse and fine aggregates from natural sourses for concrete, IS 383 : 1997, Bureau of Indian Standards, New Delhi. 18) Nevellie A.M., Concrete Technology, 1987, Longman Group, UK Limited