Acid-Modified Fly Ash Phase-Change Foamed Concrete for Insulation

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Solution Overview

Problem

Existing phase-change concrete materials face high thermal conductivity, high cost, and low structural stability, limiting their widespread application in building insulation.

Innovation Solution

A phase-change heat-storage foamed concrete is developed using acid-modified fly ash to support paraffin, combined with cement, water, and other additives, achieving a porous and lightweight structure with improved heat-absorbing capability and reduced thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If graphene oxide or hydrophobic gas-phase silicon dioxide is used to support phase-change materials, then thermal stability and heat-absorbing capability are improved, but production cost increases significantly

Engineering Contradiction:
Improvethermal stabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive graphene oxide and hydrophobic gas-phase silicon dioxide with acid-modified fly ash, which is a low-cost industrial waste material. This substitution maintains the supporting function for phase-change materials while dramatically reducing production costs, making the phase-change concrete economically viable for large-scale construction applications.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent modifies the surface properties of fly ash through acid treatment to create appropriate surface characteristics for supporting paraffin. This chemical modification changes the physical and chemical parameters of the support material, enabling it to effectively hold phase-change materials without requiring expensive alternative materials.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multi-layer graphene is used to enhance thermal conductivity, then heat transfer capability is improved, but thermal conductivity between layers remains insufficient

Engineering Contradiction:
Improveheat transfer capabilityVSAvoidthermal conductivity between layers
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

Instead of using multi-layer graphene with interlayer thermal conductivity problems, the patent employs acid-modified fly ash as a alternative support structure. The porous structure of fly ash provides adequate thermal management functionality at a fraction of the cost, avoiding the inherent limitations of graphene-based solutions.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If dense concrete structure is used to achieve high strength, then compressive strength is improved, but thermal insulation performance deteriorates

Engineering Contradiction:
Improvecompressive strengthVSAvoidthermal insulation performance
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent incorporates foam structures and porous acid-modified fly ash into the concrete matrix, creating a hierarchical porous system. These pores provide thermal insulation by trapping air and reducing heat transfer pathways, while the surrounding concrete matrix maintains structural strength, achieving a balance between mechanical performance and thermal insulation.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent creates a composite material system combining cement matrix, foam structures, acid-modified fly ash, and paraffin phase-change materials. This multi-component composite leverages the strength of cement, the insulation of foam, the surface area of modified fly ash, and the thermal regulation of paraffin to achieve both structural and thermal performance simultaneously.

Inventive Principle:
Principle #40Composite materials

4Reliability

If phase-change materials are added to improve heat-absorbing capability, then temperature regulation is enhanced, but structural stability deteriorates

Engineering Contradiction:
Improveheat-absorbing capabilityVSAvoidstructural stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses acid-modified fly ash as an intermediary carrier to hold paraffin phase-change materials within its porous structure. This intermediary structure prevents the paraffin from disrupting the concrete matrix, maintaining structural stability while enabling the phase-change material to provide thermal regulation functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The porous structure of acid-modified fly ash provides a confined environment for paraffin, preventing it from flowing freely and compromising structural integrity. The pore walls contain the phase-change material while allowing it to undergo phase transitions, thereby maintaining both structural stability and heat-absorbing capability.

Inventive Principle:
Principle #31Porous materials

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 concrete exhibits lower thermal conductivity, higher compressive strength, and lower production costs, suitable for large-scale production and effective temperature regulation in buildings, reducing energy consumption.

Implementation Method 1

a porous material adsorption method is used so that the eutectic phase-change material is adsorbed in pores of the gas-phase silicon dioxide

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

0.1-0.4% of a hydrogen peroxide decomposition catalyst

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 3

0.5-2% of an aqueous hydrogen peroxide solution, and 0.1-0.4% of a hydrogen peroxide decomposition catalyst

Methodology Applied
Scientific EffectDecomposition: Decomposition (biological)

Implementation Method 4

Phase-change materials could absorb or emit a large amount of heat during a phase change

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 5

Phase-change materials could absorb or emit a large amount of heat during a phase change

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Implementation Method 6

The phase-change heat-storage foamed concrete provided by the present disclosure has a low thermal conductivity

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS20250263340A1Phase-change heat-storage foamed concrete and preparation method and use thereof
Publication Date: 2025.08.21 HEBEI UNIV OF TECH

AI summary

A phase-change heat-storage foamed concrete, and a preparation method and use thereof are provided. The phase-change heat-storage foamed concrete provided by the present disclosure is prepared from raw materials including, in percentages by mass: 50-70% of a cement, 2-20% of a supported phase-change material, 15-35% of water, 0.1-0.5% of a water-reducing agent, 0.5-1.5% of a foam stabilizing agent, 0.5-2% of an aqueous hydrogen peroxide solution, and 0.1-0.4% of a hydrogen peroxide decomposition catalyst. The supported phase-change material includes an acid-modified fly ash and a paraffin supported on a surface and in a pore structure of the acid-modified fly ash, and the aqueous hydrogen peroxide solution has a mass percentage concentration of 25-30%.