Alkaline Nitrate Accelerator for Cold Concrete

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current setting and hardening accelerators for cement, mortar, and concrete compositions, such as calcium chloride and calcium nitrate, face challenges like corrosion issues and insufficient acceleration in cold climates, necessitating a more effective and environmentally friendly solution.

Innovation Solution

An aqueous nitrate solution with a dissolved alkaline hydroxide and optional hydroxide precipitate, maintaining a pH of at least 9.0, is used to accelerate the setting and hardening of cement, mortar, or concrete compositions, particularly effective in cold conditions and with cementitious supplementary materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If calcium chloride is used as a setting accelerator, then the setting and hardening speed is improved, but corrosion of steel reinforcement and structural damage to concrete occurs

Engineering Contradiction:

Improvesetting and hardening speedVSAvoidcorrosion and structural damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and eliminates the harmful chloride ions from the accelerator system while retaining the beneficial setting acceleration effect through the use of calcium nitrate and calcium formate, which do not cause corrosion or structural damage

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses calcium formate, a biodegradable and environmentally friendly substance that provides the necessary acceleration effect temporarily during setting and hardening, then decomposes without causing long-term harm to the concrete structure or reinforcement

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If calcium nitrate is used as a setting accelerator, then corrosion issues are avoided, but the accelerating effect is insufficient in cold climates

Engineering Contradiction:

Improvecorrosion preventionVSAvoidaccelerating effect in cold climates

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The invention combines calcium nitrate (which prevents corrosion) with calcium formate (which provides strong acceleration in cold climates), creating a synergistic mixture that achieves both corrosion protection and effective setting acceleration in cold conditions

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite accelerator system consisting of multiple chemical compounds (calcium nitrate and calcium formate) that work together to provide properties neither compound could achieve alone, specifically combining corrosion resistance with cold-weather acceleration capability

Inventive Principle:

Principle #40Composite materials

3Productivity

If amine accelerators are used to improve setting acceleration, then the setting speed is improved, but environmental hazards and user safety issues arise

Engineering Contradiction:

Improvesetting accelerationVSAvoidenvironmental hazards

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention replaces hazardous amine compounds with calcium formate, which is biodegradable and environmentally benign, thereby converting a potentially harmful accelerator system into an eco-friendly one while maintaining effective setting acceleration

Inventive Principle:

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

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 alkaline supernatant accelerates the setting and hardening process, providing economic benefits and improved performance in cold climates, while being environmentally safer than hazardous amine accelerators, and effectively enhancing the use of cementitious supplementary materials.

Implementation Method 1

The accelerator comprises a supernatant forming part of an aqueous nitrate solution and a dissolved alkaline hydroxide solid... The accelerator has a pH of at least 9.0... calcium nitrate has a pH value of only 5-8. Consequently, the accelerating effect under cold climates is not sufficient

Methodology Applied

Scientific EffectpH adjustment:

Implementation Method 2

the accelerating effect is based upon the ability of calcium nitrate to generate calcium hydroxide in order to rise the pH value

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentUS11286211B2Setting and hardening accelerator for a cement, mortar or concrete composition, optionally comprising supplementary cementitious materials, and use of this accelerator

Publication Date: 2022.03.29 YARA INTERNATIONAL ASA

AI summary

The present application relates to a setting and hardening accelerator for a cement, mortar or concrete composition, optionally comprising cement replacement materials (CSMs). The accelerator composition comprises an aqueous nitrate solution and an alkaline hydroxide. Particularly, the aqueous accelerator composition comprises between 30 and 55 w/w % of a nitrate salt as a nitrate solution and between 0.02 and 0.1 w/w % of an alkaline hydroxide, which is dissolved in the nitrate solution and, optionally, as a hydroxide precipitate in the accelerator composition, wherein the accelerator composition has a pH of at least 9.0. In case the cement, mortar or concrete composition comprises CSMs, the accelerator composition has a pH of at least 12.0. The application furthermore relates to the use of the accelerator composition according to the present application and to a method for accelerating a cement, mortar or concrete composition by reacting the composition with the accelerator according to the application, in particular at cold temperatures.