29-08-2016, 10:01 AM
INTRODUCTION
As waste continues to accumulate and availability and capacity of landfill spaces diminish, agencies are increasing application and use of recycled materials such as crumb rubber from tires in construction. The basic building materials in concrete construction are primarily aggregate and cement. The educated use of recycled materials can result in reduced cost potentials and may enhance performance; however, not all recycled materials are well suited for concrete construction applications.
USES OF OLD TYRES
Rubber from discarded tyres use in, floor mats, belts, gaskets, shoe soles, dock bumpers, seal, muffler hangers, shims and washers. 3 to 5% Rubber crumbs and upto 10% reclaimed rubber is particularly used in automobile tyres. Tyre pieces is used as fuel in cement and brick kilin. However, various local authorities are now banning the tyre burning due to atmosphere pollution. Whole tyres also used as highway crash barriers, furniture, boat bumpers on marine docks, etc.
SLUMP
It was observed slump decreases with increase rubber content by total aggregates volume, the results show that at rubber content 40% by total aggregates volume. The slump was zero and the concrete was not workable by hand. Such mixes had to be compated using a mechanical vibrator.
DENSITY
The general density reduction was to be expected due to the low specific gravity of the rubber aggregates with respect to that of the natural aggregates. The reduction in density can be a desirable feature in a number of application, including architectural application such as nailing concrete, false facades, stone backing and interior construction as well as precast concrete, light weight hollow and solid blocks, slabs etc.
AIR CONTEST
The air content increases in rubcrete mixture with increase amount of ground tyre rubber.
PLASTIC SHRINKAGE
The addition of rubber shreds to mortar reduced plastic shrinkage cracking compared to a control mortar. Despite their apparently weak bonding to the cement paste, rubber shreds provided sufficient restrain to prevent microracks from propagating.
EXPERIMENTAL PROCEDURE, MATERIALS AND MIXES
1. OPC 43-Grade as per IS: 8112-1989 Compressive strength: 7- Days = 39.8 N/mm2, 28- days = 49.5 N/mm2
2. River sand and 20 mm crushed aggregate as given in table.1
3. Tyre rubber aggregate. About 30 cm long waste tyre rubber pieces were obtained from local market, the pieces were cleaned with soap water and rinse with clean water. After drying under sun at open place, both faces of the tyre pieces were rubbed with hard wire brush to make surfaces as rough as can be done by hand. Pieces were then cut as per the grading given in table.1
4. Mix Design as given in table .2 was carried out as per guide lines of ref.5. the dry materials comprising cement, sand, aggregate and rubber aggregate was well mixed before the water and Normal Superplasticizer was gradually Included. 150 mm cubes were cast on a vibrating table demoulded 24 hours after casting, placed in a steel tub of water to cure upto specified age. The cubes were tested in saturated and surface dry conditions. The temperature of curing water remain between 26 to 28oC.
CONCLUSIONS
From experimental study and literature review it can be concluded that despite the reduced compressive strength of rubberized concrete in comparison to conventional concrete there is a potential large market for concrete products in which inclusion of rubber aggregates would be feasible which will utilize the discarded rubber tyres the disposal of which is a environment pollution problem.
As waste continues to accumulate and availability and capacity of landfill spaces diminish, agencies are increasing application and use of recycled materials such as crumb rubber from tires in construction. The basic building materials in concrete construction are primarily aggregate and cement. The educated use of recycled materials can result in reduced cost potentials and may enhance performance; however, not all recycled materials are well suited for concrete construction applications.
USES OF OLD TYRES
Rubber from discarded tyres use in, floor mats, belts, gaskets, shoe soles, dock bumpers, seal, muffler hangers, shims and washers. 3 to 5% Rubber crumbs and upto 10% reclaimed rubber is particularly used in automobile tyres. Tyre pieces is used as fuel in cement and brick kilin. However, various local authorities are now banning the tyre burning due to atmosphere pollution. Whole tyres also used as highway crash barriers, furniture, boat bumpers on marine docks, etc.
SLUMP
It was observed slump decreases with increase rubber content by total aggregates volume, the results show that at rubber content 40% by total aggregates volume. The slump was zero and the concrete was not workable by hand. Such mixes had to be compated using a mechanical vibrator.
DENSITY
The general density reduction was to be expected due to the low specific gravity of the rubber aggregates with respect to that of the natural aggregates. The reduction in density can be a desirable feature in a number of application, including architectural application such as nailing concrete, false facades, stone backing and interior construction as well as precast concrete, light weight hollow and solid blocks, slabs etc.
AIR CONTEST
The air content increases in rubcrete mixture with increase amount of ground tyre rubber.
PLASTIC SHRINKAGE
The addition of rubber shreds to mortar reduced plastic shrinkage cracking compared to a control mortar. Despite their apparently weak bonding to the cement paste, rubber shreds provided sufficient restrain to prevent microracks from propagating.
EXPERIMENTAL PROCEDURE, MATERIALS AND MIXES
1. OPC 43-Grade as per IS: 8112-1989 Compressive strength: 7- Days = 39.8 N/mm2, 28- days = 49.5 N/mm2
2. River sand and 20 mm crushed aggregate as given in table.1
3. Tyre rubber aggregate. About 30 cm long waste tyre rubber pieces were obtained from local market, the pieces were cleaned with soap water and rinse with clean water. After drying under sun at open place, both faces of the tyre pieces were rubbed with hard wire brush to make surfaces as rough as can be done by hand. Pieces were then cut as per the grading given in table.1
4. Mix Design as given in table .2 was carried out as per guide lines of ref.5. the dry materials comprising cement, sand, aggregate and rubber aggregate was well mixed before the water and Normal Superplasticizer was gradually Included. 150 mm cubes were cast on a vibrating table demoulded 24 hours after casting, placed in a steel tub of water to cure upto specified age. The cubes were tested in saturated and surface dry conditions. The temperature of curing water remain between 26 to 28oC.
CONCLUSIONS
From experimental study and literature review it can be concluded that despite the reduced compressive strength of rubberized concrete in comparison to conventional concrete there is a potential large market for concrete products in which inclusion of rubber aggregates would be feasible which will utilize the discarded rubber tyres the disposal of which is a environment pollution problem.
