# US 10,865,143 B2 · Method for recycling waste plastic into concrete

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- Number: US 10,865,143 B2
- Document ID: US10865143B2
- Status: Granted
- Kind: B2
- Application number: 16/793,476
- Filed: 2020-02-18
- Published: 2020-06-11
- Granted: 2020-12-15
- Earliest claimed: 2018-05-03
- Assignees: King Fahd University of Petroleum and Minerals
- Applicants: King Fahd University of Petroleum and Minerals
- Inventors: Mohammed Rizwan Ali; Jobin Jose; Salah U. Al-Dulaijan; Shaik Inayath Basha; Mohammed Maslehuddin
- Web page: https://patentgrep.com/patent/US10865143B2

## CPC

- C04B 18/20: from macromolecular compounds
- C04B 14/06: Quartz; Sand
- C04B 14/28: of calcium
- C04B 18/027: {Lightweight materials}
- C04B 24/2647: {containing polyether side chains}
- C04B 28/04: Portland cements
- C04B 40/0032: {Controlling the process of mixing, e.g. adding ingredients in a quantity depending on a measured or desired value (B28C7/00 takes precedence)}
- C04B 2103/32: Superplasticisers
- C04B 2111/40: Porous or lightweight materials
- C04B 2201/20: for the density
- C04B 2201/30: for heat transfer properties such as thermal insulation values, e.g. R-values
- C04B 2201/32: for the thermal conductivity, e.g. K-factors
- C04B 2201/50: for the mechanical strength
- Y02A 30/244: using natural or recycled building materials, e.g. straw, wool, clay or used tires
- Y02W 30/91: Use of waste materials as fillers for mortars or concrete
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT

## Abstract

A method of making a structural lightweight and thermal insulating concrete is described. The concrete has a coarse aggregate partly replaced by recycled plastic pieces. This enables the concrete to maintain a high compressive strength, low thermal conductivity, and low weight, while providing a use for waste plastic. The waste plastic pieces may comprise polyethylene in the form of flakes, fibers, or granules. Due to its low unit weight, adequate compressive strength and high thermal resistance the developed concrete can be used as a structural lightweight and thermal insulating concrete. The use of this concrete leads to economic and environmental benefits.

## Claims

### Claim 1

A method of recycling a waste polyolefin and making a structural lightweight concrete, the method comprising:
extruding the waste polyolefin and chopping the extruded waste polyolefin to form waste plastic pieces having a cylindrical shape with a diameter of about 2 mm and 2-5 mm long;
mixing:
12-25 wt % Portland cement;
37-57 wt % fine aggregate;
5-40 wt % coarse aggregate; and
5-12 wt % water to form a wet concrete slurry, wherein each weight percentage is relative to a total weight of the wet concrete slurry; and
curing the wet concrete slurry to produce the structural lightweight concrete,
wherein the fine aggregate is sand with an average particle size of 0.3-1.5 mm,
wherein the coarse aggregate comprises:
at least 10 wt % waste plastic pieces having an average longest dimension of 1-12 mm, and
1-90 wt % of at least one selected from the group consisting of limestone, perlite, and scoria,
wherein each weight percentage is relative to a total weight of the coarse aggregate,
wherein the limestone has an average particle size in a range of 1-20 mm,
wherein the perlite has an average particle size in a range of 1-10 mm,
wherein the scoria has an average particle size in a range of 1-30 mm, and
wherein the structural lightweight concrete has
a compressive strength of 20-40 MPa,
a thermal conductivity of 0.50-1.10 W/(m·K), and
a unit weight of 1,400-2,000 kg/m3.

### Claim 2 (depends on 1)

The method of claim 1, wherein the waste plastic pieces have a specific gravity of 0.80-1.20.

### Claim 3 (depends on 1)

The method of claim 1, wherein the waste plastic pieces have a surface roughness Ra of 1-50 μm.

### Claim 4 (depends on 1)

The method of claim 1, wherein the waste plastic pieces comprise 20-100 wt % polyethylene, relative to a total weight of the weight plastic pieces.

### Claim 5 (depends on 1)

The method of claim 1, wherein the wet slurry further comprises a polycarboxylate ether superplasticizer.

### Claim 6 (depends on 1)

The method of claim 1, wherein the wet concrete slurry has a slump of 50-150 mm.

### Claim 7 (depends on 1)

The method of claim 1, wherein the Portland cement is an ASTM C 150 cement selected from the group consisting of Type I, Type Ia, Type II, Type IIa, Type II(MH), Type II(MH)a, Type III, Type IIIa, and Type IV.

### Claim 8 (depends on 1)

The method of claim 1, wherein limestone is present, having an average particle size of 5-20 mm.