Extruded Plastic Aggregate for Concrete Strength
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Solution Overview
Problem
The use of waste plastics in concrete production results in materials with low compressive and tensile strength and is prone to deterioration due to alkali-silica reaction, especially when plastics with sugar residues are used, limiting their effectiveness as a substitute for traditional aggregates.
Innovation Solution
A method involving the extrusion of granulated waste plastic material through a die with a specific ratio of nozzle open area to land area, followed by cooling and/or coating, to produce an extruded plastic aggregate with enhanced mechanical and molecular bonding capabilities, which can be used as a partial replacement for metal aggregates in concrete, improving compressive strength and thermal properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If waste plastic material is used as aggregate in concrete, then the need for traditional aggregates is reduced and environmental impact is minimized, but the compressive strength and tensile strength of concrete deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the physical and chemical properties of waste plastic through controlled extrusion processes, including temperature control, pressure application, and additive incorporation. These parameter changes transform the plastic material into an extruded aggregate form that achieves compressive strength of at least 10 MPa, resolving the strength deterioration issue while maintaining the environmental benefit of using waste plastic
Solution Approach 2:
The patent creates composite materials by combining waste plastic with cementitious binders and potentially other modifiers during the extrusion process. This composite approach produces an extruded aggregate that integrates the advantages of both plastic (lightweight, insulation) and cement (strength, durability), achieving both the environmental goal and the mechanical strength requirement
2Quantity of substance
If waste plastic containing sugar residues is used in concrete, then material availability is improved, but alkali-silica reaction occurs causing deterioration
Solution Approach 1:
The patent applies preliminary action by performing cleaning and treatment of waste plastic material before the extrusion process. This pre-treatment removes sugar residues and other contaminants that would cause alkali-silica reaction, while still allowing the use of a wide range of waste plastic materials. The preliminary cleaning action prevents future deterioration while maintaining material availability
Solution Approach 2:
The patent converts the harmful effect of sugar residues into a benefit by using the extrusion process to eliminate these residues through heat treatment and mechanical processing. The same extrusion process that shapes the aggregate also removes the problematic sugar content, transforming a harmful substance into a useful purification mechanism
3Weight of moving object
If light weight aggregate concrete is used, then dead load is reduced and thermal properties are improved, but compressive strength deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the density and porosity of the extruded plastic aggregate during manufacturing. By adjusting extrusion parameters such as temperature, pressure, and cooling rate, the patent produces aggregates with optimized density that provide both lightweight properties (reducing dead load) and sufficient compressive strength (at least 10 MPa), resolving the strength-deterioration issue while maintaining weight advantages
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method produces a concrete product with compressive strengths ranging from 10 to 50 MPa, offering a viable alternative to traditional aggregates while reducing the need for extensive cleaning of waste plastics and minimizing environmental impact.
Implementation Method 1
introducing the granulated waste plastic material into an extruder having a die, and extruding the granulated waste plastic material through the extruder to generate an extruded plastic aggregate
Implementation Method 2
extruding the granulated waste plastic material through the extruder to generate an extruded plastic aggregate
Implementation Method 3
treating the extruded plastic aggregate by i) cooling the extruded plastic aggregate
Data Source
AI summary
The invention generally relates to a method of making a plastic aggregate, and its use to make concrete products. The aggregate is formed by providing a granulated waste plastic material, introducing the granulated waste plastic material into an extruder having a die, the die having a ratio of die nozzle open area to die land area of about 1:10 to about 1:40, and extruding the granulated waste plastic material through the extruder to generate an extruded plastic aggregate. The method can include the presence of controlled cooling, the addition of additives and treatment of the surface of the aggregate to produce a desired aggregate that can be used to make a concrete product with desired properties, such as compressive strength and weight.