Geopolymer Cementitious Compositions Dimensional Stability

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Solution Overview

Problem

There is a need for dimensionally stable fly ash-based geopolymeric compositions that reduce shrinkage, initial and final temperature behavior, and setting time to improve the manufacturing of cementitious concrete products with enhanced strength.

Innovation Solution

The development of geopolymer cementitious compositions incorporating thermally activated aluminosilicate materials, calcium aluminate cements, calcium sulfates, and alkali metal chemical activators, which provide improved dimensional stability, extended working times, and modified temperature generation without compromising compressive strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If traditional geopolymer compositions are used, then setting time is reduced, but dimensional stability deteriorates due to high shrinkage

Engineering Contradiction:

Improvesetting timeVSAvoiddimensional stability

Core Design Contradiction:

Loss of timeVSStability of the object's composition

Solution Approach 1:

The patent uses a composite binder system combining geopolymer binder with Class F fly ash and calcium aluminate cement. This composite approach allows the material to achieve both rapid setting (within 24 hours) and dimensional stability, as the calcium aluminate cement component compensates for the shrinkage issues of traditional geopolymer compositions while maintaining the fast setting characteristic.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters by incorporating specific amounts of Class F fly ash (10-50 parts by weight per 100 parts geopolymer binder) and calcium aluminate cement. This parameter adjustment transforms the material properties to achieve both rapid setting and low shrinkage, resolving the contradiction between setting time and dimensional stability.

Inventive Principle:

Principle #35Parameter changes

2Strength

If thermally activated aluminosilicate materials are used, then compressive strength is improved, but temperature generation increases

Engineering Contradiction:

Improvecompressive strengthVSAvoidtemperature generation

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The patent controls the thermal behavior by adjusting the proportion of thermally activated aluminosilicate materials (Class F fly ash) to 10-50 parts by weight per 100 parts geopolymer binder. This parameter optimization ensures adequate compressive strength development while limiting excessive temperature generation during curing.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If setting time is reduced, then productivity is improved, but working time is insufficient

Engineering Contradiction:

Improvesetting timeVSAvoidworking time

Core Design Contradiction:

ProductivityVSDuration of action of moving object

Solution Approach 1:

The patent optimizes the composition parameters including water-to-binder ratio and additive concentrations to achieve a balanced setting profile. The material sets within 24 hours for productivity while maintaining adequate working time for placement and finishing operations, resolving the contradiction between rapid setting and sufficient working time.

Inventive Principle:

Principle #35Parameter changes

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 compositions exhibit significantly reduced shrinkage, extended setting times, and increased compressive strength, making them suitable for applications where traditional geopolymer products fail due to shrinkage or strength loss, while maintaining excellent durability under wet conditions.

Implementation Method 1

The activator is mixed with water to form an aqueous solution

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

thermally activated geopolymer aluminosilicate materials...alkali metal chemical activator...form geopolymer cementitious compositions

Methodology Applied

Scientific EffectGeopolymerization: Chemical Bonding

Implementation Method 3

calcium aluminate cements...mixed with water...setting and hardening

Methodology Applied

Scientific EffectHydration: Mineral Hydration

Implementation Method 4

modified temperature generation...exothermic reaction...temperature rise

Methodology Applied

Scientific EffectExothermic reaction: Exothermic Reaction

Data Source

PatentEP2841390B1Dimensionally stable geopolymer compositions and method

Publication Date: 2021.07.28 UNITED STATES GYPSUM CO

Figure 1A
Figure 1B
Figure 2~3A

AI summary

A method for making geopolymer cementitious binder compositions for cementitious products such as concrete, precast construction elements and panels, mortar and repair materials, and the like is disclosed. The geopolymer cementitious compositions of some embodiments are made by mixing a synergistic mixture of thermally activated aluminosilicate mineral, calcium aluminate cement, a calcium sulfate and a chemical activator with water