Calcium Formate Additive for Hydraulic Binder Hardening

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Solution Overview

Problem

Existing hardening accelerators for hydraulic binders, such as calcium silicate hydrate-based additives, face issues like loss of activity upon drying, corrosiveness, oxidizing effects, hygroscopicity, and inadequate early strength development, limiting their use in dry binders and concrete applications.

Innovation Solution

A dry additive comprising a polymeric dispersant with anionic or anionogenic groups and polyether side chains, combined with calcium silicate hydrate particles, which acts as a hardening accelerator, enhancing early strength development in hydraulic setting compositions without the limitations of previous additives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If calcium silicate hydrate-based hardening accelerators are used, then early strength development is improved, but activity is lost upon drying

Engineering Contradiction:

Improveearly strengthVSAvoidactivity retention after drying

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters by using calcium formate instead of traditional calcium compounds, and controls the molar ratio of calcium to silicon (0.6-2.0) and calcium to water (0.6-6.0) to optimize both early strength development and drying stability. This parameter optimization resolves the contradiction by finding a compositional sweet spot that maintains activity after drying while accelerating hardening.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite hardening accelerator system combining calcium formate with specific sulfonic acid compounds and polymeric dispersants. This composite approach allows the calcium silicate hydrate particles to maintain their hardening-accelerating properties while the accompanying compounds prevent activity loss during drying, thus resolving the contradiction between early strength improvement and activity retention.

Inventive Principle:

Principle #40Composite materials

2Speed

If calcium chloride is used as calcium source, then hardening acceleration is achieved, but corrosive effects occur

Engineering Contradiction:

Improvehardening speedVSAvoidcorrosiveness

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the harmful calcium chloride with calcium formate, which provides the necessary calcium ions for hardening acceleration without the corrosive chloride ions. The formate ion serves as a benign alternative that maintains the beneficial hardening speed while eliminating the harmful corrosiveness, effectively converting the harmful calcium source into a beneficial one.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Speed

If calcium nitrate is used, then hardening acceleration occurs, but oxidizing effects are produced

Engineering Contradiction:

Improvehardening speedVSAvoidoxidizing effects

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent substitutes calcium nitrate with calcium formate, replacing the oxidizing nitrate ion with the non-oxidizing formate ion. This substitution maintains the hardening acceleration benefit while eliminating the harmful oxidizing effects, thus converting a harmful calcium source into a beneficial one.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Speed

If calcium acetate is used, then hardening acceleration is achieved, but hygroscopicity increases

Engineering Contradiction:

Improvehardening speedVSAvoidwater absorption

Core Design Contradiction:

SpeedVSLoss of substance

Solution Approach 1:

The patent replaces hygroscopic calcium acetate with calcium formate, which exhibits reduced hygroscopicity. This substitution maintains the hardening acceleration benefit while reducing unwanted water absorption, effectively converting a harmful material property into a beneficial one.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

5Speed

If calcium sulfate is used, then hardening acceleration occurs, but solubility problems arise

Engineering Contradiction:

Improvehardening speedVSAvoidsolubility

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent substitutes calcium sulfate with calcium formate, replacing the poorly soluble sulfate with the highly soluble formate. This substitution maintains hardening acceleration while improving solubility, thus converting a harmful solubility characteristic into a beneficial one.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

6Productivity

If hardening accelerators are used to shorten curing time, then productivity increases, but early strength development may be inadequate

Engineering Contradiction:

Improveproduction cycle speedVSAvoidearly compressive strength

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent optimizes multiple parameters simultaneously: the molar ratio of calcium to silicon (0.6-2.0), calcium to water (0.6-6.0), and the specific composition including sulfonic acid compounds and polymeric dispersants. This multi-parameter optimization ensures that the hardening accelerator provides both adequate early strength development and sufficiently fast curing time to improve productivity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite system combining calcium formate with sulfonic acid compounds and polymeric dispersants that work synergistically. This composite approach ensures both adequate early strength (through controlled calcium silicate hydrate formation) and fast curing (through the accelerating effect of the composite composition), thus resolving the contradiction between productivity and early strength.

Inventive Principle:

Principle #40Composite 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 additive significantly improves compressive strength within 6, 10, and 24 hours, enabling early deshuttering of concrete and shorter production cycles, while maintaining effectiveness in dry form and avoiding the drawbacks of previous solutions.

Implementation Method 1

reacting a calcium compound, which among others may be calcium sulfamate, with a silicon compound

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

The average molecular weight Mw of the polymer as determined by gel permeation chromatography (GPC)

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 3

accelerators, have a capacity to shorten the curing procedure

Methodology Applied

Scientific EffectHydration: Mineral Hydration

Data Source

PatentUS9802864B2Additive for masses that set hydraulically

Publication Date: 2017.10.31 BASF SE

AI summary

The invention relates to an additive which can be used as a hardening accelerator for hydraulically setting compositions, comprising a) at least one polymeric dispersant comprising structural units having anionic or anionogenic groups and structural units having polyether side chains, b) at least one sulfonic acid compound of the formula (I)in which A1 is NH2, NHMe, NMe2, N(CH2—CH2—OH)2, CH3, C2H5, CH2—CH2—OH, phenyl, or p-CH3-phenyl and Kn+ is an alkali metal cation, or one equivalent of a cation selected from Ca2+, Mg2+, Sr2+, Ba2+, Zn2+, Fe2+, Fe3+, Al3+, Mn2+, or Cu2+, and c) calcium silicate hydrate particles.