Method for forming lightweight concrete containing waste plastic

Patent metadata

Field	Value
Publication number	US-11124451-B2
Application number	US-202016793515-A
Country	US
Kind code	B2
Filing date	Feb 18, 2020
Priority date	May 3, 2018
Publication date	Sep 21, 2021
Grant date	Sep 21, 2021

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.

First claim

The invention claimed is:

1. A method of forming a structural lightweight concrete comprising waste plastic, the method comprising:
mechanically grinding a waste polyolefin to form waste plastic pieces having a two dimensional thin shape with a length and width in the range of 2-6 mm;
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/m 3 .

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

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

4. 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.

5. The method of claim 1 , wherein the wet concrete slurry further comprises 0.1-2.0 wt % of a superplasticizer relative to a total weight of the wet concrete slurry.

6. The method of claim 5 , wherein the superplasticizer is a polycarboxylate ether.

7. The method of claim 5 , wherein the wet concrete slurry has a slump of 50-150 mm.

8. 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.

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

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Ali Mohammed Rizwan
• Jose Jobin
• Al-Dulaijan Salah U
• Basha Shaik Inayath
• Maslehuddin Mohammed

Classifications

• Y02W30/91

  Use of waste materials as fillers for mortars or concrete · CPC title

• Y02A30/244

  using natural or recycled building materials, e.g. straw, wool, clay or used tires · CPC title

• C04B2111/40

  Porous or lightweight materials · CPC title

• C04B28/04

  Portland cements · CPC title

• C04B2201/50

  for the mechanical strength · CPC title