Hydraulic Binder Accelerator Using Calcium Silicate Seeds

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Solution Overview

Problem

Existing cement setting accelerators are either unstable, costly, or do not provide sufficient acceleration of the setting process, and they often require liquid forms that are not suitable for all applications, particularly in dry batch products.

Innovation Solution

A hydraulic binder comprising a cement, a water-soluble calcium salt, and a silicate compound, such as sodium silicate, in specific proportions, which can be mixed in powder form to accelerate the setting and hardening of cement, forming hydrated calcium silicate seeds that enhance the hydration kinetics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If existing cement setting accelerators are used, then the setting process is accelerated, but they are unstable, costly, or require liquid forms that are not suitable for all applications

Engineering Contradiction:
Improvesetting accelerationVSAvoidstability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The invention changes the chemical parameters by using a specific combination of calcium salt and silicate compound in controlled proportions (0.1-3.5% by dry weight each) to achieve stable setting acceleration. This parameter optimization resolves the contradiction by finding the right balance between acceleration effectiveness and chemical stability in powder form.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite accelerator system combining calcium salt and silicate compound together with cement, forming hydrated calcium silicate seeds in situ. This composite approach provides both the desired setting acceleration and stability, while being suitable for dry batch applications.

Inventive Principle:
Principle #40Composite materials

2Speed

If chemical accelerators are added to cement, then the setting speed is accelerated, but the cost increases

Engineering Contradiction:
Improvesetting speedVSAvoidcost
Core Design Contradiction:
SpeedVSQuantity of substance

Solution Approach 1:

The invention optimizes the concentration parameters of the accelerator components, using calcium salt and silicate compound each at 0.1-3.5% by dry weight of cement. This controlled parameter range achieves effective setting acceleration while minimizing the quantity of additives required, thereby controlling costs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The silicate compound and calcium salt react in situ to form hydrated calcium silicate seeds that self-generate the acceleration effect. This self-service mechanism eliminates the need for expensive external accelerator additives while maintaining effective setting speed enhancement.

Inventive Principle:
Principle #25Self-service

3Productivity

If crystallization seeds are incorporated into cement, then the hardening is accelerated, but the seeds are unstable and require stabilization with polymer which increases cost

Engineering Contradiction:
Improvehardening accelerationVSAvoidcost
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

Instead of incorporating pre-made crystallization seeds that require stabilization, the invention uses silicate compound and calcium salt that self-generate hydrated calcium silicate seeds in situ during mixing. This self-service approach eliminates the need for expensive polymer stabilizers while maintaining hardening acceleration.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The silicate compound and calcium salt are pre-mixed with the cement in dry form, so that when water is added, the crystallization seeds form immediately and uniformly throughout the mixture. This preliminary preparation ensures consistent hardening acceleration without requiring additional stabilization steps.

Inventive Principle:
Principle #10Preliminary action

4Ease of operation

If accelerator is added in liquid form, then the setting is accelerated, but it is not possible to use in dry batch products

Engineering Contradiction:
Improveaccelerator applicationVSAvoidapplication range
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The invention changes the physical state parameter of the accelerator from liquid to powder form by using dry-mixable calcium salt and silicate compound. This parameter change enables the accelerator to be used in dry batch products while maintaining ease of application through simple dry mixing before adding water.

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

This combination provides a synergistic acceleration of cement setting with improved short-term strength without compromising long-term mechanical properties, offering a stable and cost-effective solution for various construction applications.

Implementation Method 1

In the presence of water, cement particles dissolve on the surface and release ionic species, which react with each other to form hydrates, notably silicate and calcium hydrates

Methodology Applied
Scientific EffectHydration: Hydrates

Implementation Method 2

The crystallization seeds trigger crystal precipitation: they cause and direct the crystallizations so as to accelerate hardening and increase resistance

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 3

As soon as the cement is mixed with the water called mixing water, the anhydrous cement particles transform into gels then into precipitates of hydrated microcrystals

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 4

which react with each other to form hydrates, notably silicate and calcium hydrates, which precipitate in the pore solution and cause the material to harden

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Data Source

PatentEP2714612B1Hydraulic binder comprising an accelerator, its application and process for preparation of a construction material
Publication Date: 2019.07.17 SAINT-GOBAIN WEBER SA
  • EP2714612B1 patent drawingFigure 1~2
  • EP2714612B1 patent drawingFigure 3~4

AI summary

The present invention relates to a novel cement setting agent made up of sodium silicate and a calcium salt.