Replacement of M30 Concrete with M20 Concrete using Waste Tyre Steel Fiber in Rigid Pavement

Every year large quantity of waste tyres are generated. To address these waste tyres creates an increasing problem,these waste tyres can be used to improve the properties of concrete. The aim of this study is to replace M30 grade concrete with M20 concrete using waste tyre steel fiber in rigid pavements. We incorporated the steel strips of waste tyre with M20 grade concrete at varying percentages 0%, 0.5%, 1%, 1.5% and 2% to the weight of concrete mix of M20. It increases the Compressive Strength, Flexural Strength and Split Tensile Strength of M20 WTSFRC than M30 grade concrete used in rigid pavements. It increases the impact, abrasion, and resistance in the concrete, it reduces the permeability of concrete, reduces the bleeding in fresh concrete and makes the concrete more impermeable in the hardened stage. Introducing these kind of wastes(used tyres) is the great task, keeping the environment factor into mind as it can reduce the pollution level. When waste scrap steel fibers are reinforced with concrete it is called Waste Tyre Steel Fiber Reinforced Concrete(WTSFRC).


I. INTRODUCTION
The poor performance of conventional concrete made the researchers to think about the way by which the performance of the concrete can be increased. Plain concrete has deficiencies like low tensile strength and allow strain at fracture. In order to improve the properties of concrete we incorporated the steel strips of rubber tyres with M20 concrete, it increases the flexural, compressive and split tensile strength. This type of concrete can be used to replace M30 concrete with M20 concrete it increases the impact, abrasion and resistance in the concrete. It reduces the permeability of concrete. This type of concrete can be used in building, bridges, dams etc. The fibers obtained from tyre strips reduce the bleeding in fresh concrete.
II. LITERATURE VIEW Fiber reinforced concrete is a composite material and has gain popularity from last so many years. If we look into history Lankard was the person, who used fibers in 1997 and proved that the fiber reinforced concrete has high strength as compared to conventional concrete. He worked on steel fiber reinforced concrete and done so many researches on it. Balaguru and Shah (1992) have reported that the fibers that are long and at higher volume fractions were found to ball up during the mixing process called balling and causes the 4. To design M20 grade of concrete as per IS code which will be used as reference mix. 5. To study the performance of concrete containing different percentages of waste tyre bead steel fiber such as workability. 6. To determine the Compressive strength,Split Tensile strength and Flexural strength of M20 concrete containing different percentages of waste tyre bead wires. 7. To compare the compressive strength, flexural strength, split tensile strength of M30 concrete with M20 concrete at varing percentage of waste tyre steel fibers. 8. Introducing these kind of wastes(used tyres) is the great task, keeping the environment factor into mind as it can reduce the pollution level.

IV. METHODOLOGY
The WTSFRC (Waste Tyre Steel Fiber Reinforced Concrete) is a composite material consists of ordinary portland cement, aggregate and steel fibers. Normal plain concrete is brittle weak in tension. In order to solve this problem fibers are added, it comes under the category of steel fiber reinforced concrete. The waste tyre steel fiber reinforced concrete consists of cement, fine aggregates, coarse aggregates and waste tyre steel strip fibers. The specimens were prepared and the strength were checked after 7 days and 28 days. The test were conducted on both plain M30 concrete and M20 waste tyre fiber reinforced concrete. It was seen from the experimental programe that the compressive strength, flexural strength and split tensile strength increases upto the optimum dosage of 1% in M20 concrete, which is greater than M30 concrete (compressive strength, flexural strength and split tensile strength). The experimental procedure consists of following steps:

A. COMPRESSIVE STRENGTH TEST
In this test we take specimen from the curing tank after the time period of 7 and 28 days. By this we calculated the compressive strength after 7 & 28 days. Specimen were tested on 200 tonnes capacity of CTM. The specimen is placed centrally between the two compression plates, such that the center of moving head is vertically above the center of specimen. Load is applied on specimen by moving the movable head. The load and corresponding contraction are measured at different intervals. Load is applied until the specimen fails. The strength is determined by conduct of a compression test. The load is applied gradually at the constant rate 14 N/mm 2 Unit of failure of specimen takes place. This test was performed as per IS Code 516-1959. The compressive strength is calculated as Load /Area.

B. SPLIT TENSILE STRENGTH TEST
The Split tensile test was conducted according to IS Code 516-1999. The concrete is very weak in tension due to its brittle nature and is not accepted to resist the direct tension. The concrete develops cracks when subjected to tensile forces. Thus, it is necessary to determine the tensile strength of concrete to determine the load at which the concrete members may crack. Split tensile strength test on concrete cylinder is a method to determine the tensile strength of concrete. The specimens were casted in cylinders and proper curing was done. After that these specimens were taken out from water after 7 days of curing and wipe out water from the surface of specimen and were tested under split tensile testing machine of 100 tonnes bearing capacity. The load was applied gradually at the rate of 2.4N/mm 2 /minute until the failure takes place in the specimen. Split Tensile strength (MPa) = 2P / π DL, Where, P = failure load, D = diameter of cylinder = 150 mm, L = length of cylinder = 300 mm.

C. FLEXURE STRENGTH TEST
Flexural strength, also known as modulus of rupture, or bend strength, or transverse rupture strength is a material property defined as the stress in a material just before it yields in a flexural test. The flexural strength represents the highest stress experienced within the material at its moment of yield. It is measured in terms of stress. The Flexure strength of specimen was conducted as per IS Code 516-1959. The surface of the machine was cleaned and oiled, after that the specimen is put on the surface with contact to rollers. The axis of the specimen was carefully aligned with the axis of loading device. The load of 7 Kg/cm 2 /min. The load is applied gradually to the specimen until the specimen show the signs of failure. The Flexural Strength is given by Flexural strength (MPa) = (P x L) / (b x d 2 ), Where, P = Failure load, L = Centre to center distance between the support = 700 mm, b = width of specimen=150 mm, d = depth of specimen= 150 mm.

B. FLEXURAL STRENGTH F O R M 3 0 C O N C R E T E :
Flexural strength were conducted on plain mortar and waste tyre steel fiber reinforced concrete. The tested beams of 150mm×150mm×700mm under two point loads because of small span between the supports. The effective span was taken 640mm. The flexural strength were tested on specimens after 7 and 28 days The flexural strength after 7 days is 1.97 MPa and flexural strength after 28 days is 3.01MPa.  It is seen from the above tables and figures that adding the waste tyre steel strip. Fibers with concrete that it increases the compressive Strength upto resulted 1% both at 7 and 28 days respectively. Hence the results shows that it increases the compressive behavior and helps in improving the properties of M20 concrete.

E. FLEXURAL STRENGTH FOR M20 WTSFRC:
Flexural strength were conducted on plain mortar and waste tyre steel fiber reinforced concrete. The tested beams of 150mm×150mm×700mm under two point loads because of small span between the supports. The effective span was 15 1.The experimental work showed that the properties of M20 grade concrete improved due to incorporation of waste tyre steel fiber strips than M30 grade concrete in rigid pavements. 2.The experimental work also showed that the Workability of M20 waste tyre steel fiber reinforced concrete gets reduced as we increase the percentage of fibers. 3. It also showed that the Compressive Strength of M20 WTSFRC gets increased upto 10% with 1% of waste tyre steel fiber used as compared to M30 grade concrete in rigid pavements. 4. The Flexural Strength of M20 WTSFRC gets increased upto 25% as compared to M30 grade concrete in rigid pavements. 5. The Split Tensile Strength of M20 WTSFRC gets increased upto 20% with 1% of waste tyre steel fiber used as compared to M30 grade concrete. 6. The experimental work also shows that the maximum Compressive, Flexural and Tensile Strength of M20 WTSFRC gained at the dosage of 1% and beyond it again decreases. 7. The specimen prepared by incorporating the M20 grade concrete with waste tyre steel strip fibers showed good strength and does not collapse suddenly as compared to M30 grade concrete. Hence it can be concluded that we can replace M30 grade concrete with M20 grade concrete using waste tyre steel fiber in rigid pavements.

FUTURE SCOPE OF STUDY
The behavior of WTSFRC depends upon aspect ratio. 1. Effect of fiber contents from 3 to 12% on the structural behavior of WTSFRC. 2. Effect of use of Rice Husk and other materials on the structural behavior of WTSFRC. 3. Effect of fiber content on ductility and toughness of WTSFRC. 4. To design the overlay over M20 WTSRC in rigid pavements.