Hydrating Cementitious Patch Composition for Crack Resistance

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Solution Overview

Problem

Current patch formulations harden by evaporating water, leading to cracking, loose fit, and dislodging from surfaces, and lack re-workability and longer pot life, making them unsuitable for large-scale applications.

Innovation Solution

A hydrating patch composition comprising Portland cement, Calcium Sulfate Hemihydrate, Gypsum, Calcium Aluminate Cement, Calcium Carbonate, and various fillers and binders, which set by hydration rather than evaporation, providing better adhesion and allowing for easier application and sanding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If patch formulations harden by evaporating water, then the patch sets and hardens, but cracking, loose fit and dislodging occur

Engineering Contradiction:
Improvepatch hardnessVSAvoidadhesion to surface
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the fundamental hardening mechanism from evaporative (physical parameter change) to hydrating (chemical reaction). The composition uses calcium aluminate cement and calcium sulfate hemihydrate that set through chemical hydration reactions, eliminating the shrinkage and cracking associated with water evaporation while maintaining hardening and strength development.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite cementitious composition containing multiple components: calcium aluminate cement, calcium sulfate hemihydrate, Portland cement, and various fillers. This composite approach combines the advantages of different materials to achieve both strong adhesion through chemical bonding and adequate hardness, resolving the contradiction between reliability and strength.

Inventive Principle:
Principle #40Composite materials

2Loss of time

If traditional patch formulations are used, then the patch sets quickly, but re-workability and pot life are limited

Engineering Contradiction:
Improvesetting timeVSAvoidre-workability
Core Design Contradiction:
Loss of timeVSEase of operation

Solution Approach 1:

The patent creates a dynamic system where the hydration reaction progresses gradually rather than rapidly. The composition allows the user to control the working time and can re-temper the material by adding water during the hydration process, providing flexibility and extended re-workability while still achieving final set and hardening.

Inventive Principle:
Principle #15Dynamics

3Strength

If patch formulations are made for high strength, then compressive strength increases, but ease of troweling and application decreases

Engineering Contradiction:
Improvecompressive strengthVSAvoidtrowelability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent optimizes the water-to-cement ratio and uses specific filler materials to achieve a composition that maintains workable consistency for easy troweling while developing high compressive strength through the hydration reaction. The gradual setting characteristic allows adequate working time for proper application and finishing.

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 hydrating patch compositions offer improved adhesion, reduced shrinkage, higher compressive strength, and longer pot life, enabling larger volumes and deeper applications with reduced waste, while maintaining a smooth, easy-to-trowel consistency.

Implementation Method 1

hydrating patch compositions... which set by hydration rather than evaporation

Methodology Applied
Scientific EffectHydration: Mineral Hydration

Data Source

PatentUS9708220B2Cementitious patch compositions and methods
Publication Date: 2017.07.18 UNITED STATES GYPSUM CO

AI summary

A cementitious hydrating patch composition is provided with improved strength and abrasion resistance. The patch comprises Portland cement in the amount from 2% to 10%, Calcium Sulfate Hemihydrate in the amount from 2% to 30%, Gypsum in the amount from 0% to 15%, Calcium Aluminate Cement in the amount from 15% to 40%, Calcium Carbonate in the amount from 0% to 40%, at least one filler in the amount from 1% to 30%; and at least one binder in the amount from 10% to 40%, wherein all amounts are based on dry weight of the composition. Methods of preparing and using the patch composition are provided as well.