“RECYCLED PLASTICS USED AS COARSE AGGREGATE FOR …

"RECYCLED PLASTICS USED AS COARSE AGGREGATE FOR CONSTRUCTIONAL CONCRETE"

PROJECT REFERENCE NO. : 37S1114

COLLEGE : SJB INSTITUTE OF TECHNOLOGY, BANGALORE BRANCH : CIVIL ENGINEERING GUIDE : R L RAMESH STUDENTS : ASHARANI K M

DHIRAJ KATARI V C PRUTHVI SAGAR D S SAHANA R

Keywords: Recycled plastic, Replacement of Coarse aggregate, compressive strength,

plastic concrete.

Introduction:

Landfill sites are becoming over crowded and expensive for waste disposal, efforts are made to minimize the quantities of materials that are delivered to landfills. The threat due to leaching of non-biodegradable materials like waste plastics, scrap tyres. e-waste may contaminate the soil and ground water. If the production of waste cannot be prevented, then it is attractive to create an alternative use in another process instead of disposal. The benefits of plastic recycling can be economically advantageous, due to abundant availability lower cost for mixing with other variants like concrete, bitumen etc.The development of concrete with nonconventional aggregate, such as polystyrene foam wastes, HDPE, polyethylene terephthalate (PET), and other plastic materials has been investigated for use in concrete in order to improve the properties of the concrete and reduce cost. The use of such plastic wastes in concrete will contribute to the sustainability of the concrete design and the natural environment.

The project aims at use of recycled plastic in concrete as a partial replacement of Coarse aggregate. The maximum percentage of aggregate replaced by shredded plastic as been determined based on detailed experimental study. The waste plastic of LDPE (Low density

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poly Ethylene ) is collected from Bangalore south localities and mixed with OPC and sand in varying proportions (0%, 20%,30%,40%). The compressive strength for each variant is determined in laboratory.

Objectives:

? To compare the compressive strength and Density of Recycled Plastics used as Coarse Aggregate for Constructional Concrete with the Conventional concrete

? To know its applications in construction industry. ? To reduce the pressure on naturally availability materials by replacing it with

Recycled plastic aggregate ? To compare the physical characteristics of natural aggregate with Plastic recycled

aggregate. ? To study the behavior of fresh and hardened concrete with polymer waste coarse

aggregate and compare its properties to those of conventional concrete ? To produce lightweight polymer concrete for multi-purpose use

It represents an environmental friendly and economical viable solution, for utilization of waste plastic.

Methodology:

For the characterization of the recycled plastic concrete the compressive strength of the specimen are determined along with mechanical properties (like, Density, Specific Gravity, Fineness modulus etc...) to as representative parameter for the modified concrete. Firstly the values of compressive strength for plain cement concrete is determined (M20). The compressive strength value is compared for 7-days, 14-days and 28-days with the replaced plastic concrete of varying proportions. Materials Aggregates: Confirming to IS 383:1970 ? Specification for coarse and fine aggregates from natural sources for concrete Cement: (Birla 53 grade) Confirming to IS 12269:1987 Specification for 53 grade ordinary Portland

Water: Potable water

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Plastic: Waste trash bag plastics were collected from the landfill and from other locations in

the environment and used to manufacture lightweight aggregates. The plastic waste sheet was shaped as desired, e.g.. The plastic waste aggregate was modified by heat treatment (160?C200?C) in Plastic Granule Recycling Machine. Then, the hot aggregate was removed from the Machine and allowed to cool at room temperature, but they were a mixture of angular shapes and round shapes, much like crushed stone. And the obtained plastic granules are grinded in a grinding mill to a 20mm down size

Method: Mixing the raw materials, i.e., water, Portland cement, sand, and coarse aggregate, was mixed. The design mix proportions were 1:1.5:3. The experiment are conducted replacing coarse aggregate with shredded plastic waste (of 20mm down size LDPE). The series of experiments are named as: ((A20-80:20); (A30-70:30); (A40-60:40) and (A0100%)) crushed stone) with the water to cement ratio of 0.5. The mixing process created a homogeneous mixture to ensure the proper coating of cement on the aggregate. Thus, the mixing process must be thorough and not rushed. The compressive strength of the sample cubes are tabulated in Table no.1Table 1 compressive strength of cubes

Mixing proportion

series

COMPRESSIVE STRENGTH IN N/MM

2

7 DAYS

14DAYS

28 DAYS

A-0

18.6

28.25

33.6

A-20

20.62

22.87

29.3

A-30

19

21.06

24.29

A-40

8.32

15.76

21.5

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Chart Title

40

35

30

25

20

15

10

5

0

7dy

A-0

A-20

A-30

A-40

COMPRESSIVE STRENGTH IN N/MM 2

COMPRESSIVE STRENGTH IN N/MM 2

COMPRESSIVE STRENGTH IN N/MM 2

COMPRESSIVE STRNGHT IN Pa

40 35 30 25 20 15 10

5 0

A0

COMRESSIVE STRENGTH COMRESSIVE STRENGTH COMRESSIVE STRENGTH

A20

A30

A40

PLASTIC CONTENT IN %

Fig 1.1 Variation of Compressive Strength of Concrete cube with percentage of waste plastic replaced as coarse aggregate

Results and Discussion:

The experimental results have shown the use of waste plastic material in making concrete/mortar can provide an alternative solution to minimize the environmental impact due to unscientific disposal of waste plastic. The following conclusions were drawn:

? The properties of concrete containing various percentage of plastic (0%, 20%, 30%, 40%) were tested for its physical properties and compressive strength.

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? The waste plastic used for experiments is of LDPE (Low Density Poly Ethylene), type of 20? size with fineness modulus value of 7.59 and specific gravity of waste plastic is found to be 1.1.

? The compressive strength of RPC is compared with plain concrete (fig 1.1) and it is found that the compressive strength up to 80% is achieved for a mix of waste plastic up to 30% (as a replacement for coarse aggregate) in concrete. Hence it is recommended for light weight concrete structures.

? The mechanical properties of the RPC did not display any notable differences depending on the color of the plastic waste.

? This research also has potential application for the production of lightweight concrete, cost savings for raw materials, for minimizing the amount of polymer wastes in landfills, and the creation of decorative, attractive landscaping products.

Scope of future work:

? The Split tensile strength of RPC has to be carried out to ascertain the tensile behavior of the modified concrete.

? Experimental study has to be conducted for other varieties of plastic like HDPE, PP ,PET.

? The durability of such a concrete has to be tested for beams and columns with varying proportions of waste plastic at different ages.

? The fire resistance of RPC has to be tested under controlled condition to ascertain the fire safety of the building.

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