Cementitious Admixture Strength Enhancement via Calcium Silicate Hydrate
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Solution Overview
Problem
Cementitious compositions with high pozzolanic content face challenges in achieving predictable and high early and final compressive strengths, as existing admixtures often fail to provide consistent performance across various formulations and applications.
Innovation Solution
A strength enhancing admixture comprising calcium silicate hydrate, alkanolamine, and inorganic accelerators, combined with carbohydrates, which are formulated to improve the early and final compressive strengths of cementitious compositions, particularly those with high pozzolanic content, by optimizing the reaction conditions and composition ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high pozzolanic content is used in cementitious compositions, then workability and setting properties are improved, but early and final compressive strengths are reduced and become unpredictable
Solution Approach 1:
The patent changes the chemical parameters of the admixture by incorporating specific compounds (calcium chloride, calcium nitrate, triethanolamine, and sugars) in optimized proportions. This modifies the chemical environment to accelerate cement hydration without being inhibited by high pozzolanic content, thereby achieving both good workability and high compressive strength
Solution Approach 2:
The patent creates a composite admixture system that combines multiple components (inorganic accelerators like calcium chloride and calcium nitrate, organic accelerators like triethanolamine, and workability modifiers like sugars) to simultaneously address the conflicting requirements of workability and strength development in high pozzolanic cement compositions
2Ease of operation
If conventional admixtures are used in high pozzolanic cement compositions, then workability is maintained, but strength development is retarded and performance becomes unpredictable
Solution Approach 1:
The patent optimizes the concentration parameters of various admixture components, specifically using calcium chloride (0.5-5% by weight), calcium nitrate (0.5-5% by weight), triethanolamine (0.1-2% by weight), and sugars (0.1-1% by weight). These optimized parameters ensure reliable and predictable strength development while maintaining workability in high pozzolanic cement compositions
Solution Approach 2:
The patent introduces triethanolamine and sugar compounds as intermediary substances that mediate between the pozzolanic materials and the cement matrix. These intermediaries facilitate controlled hydration reactions, making the strength development process more predictable despite the presence of high pozzolanic content
3Strength
If early strength enhancement is achieved through conventional methods, then early compressive strength increases, but final strength and workability are compromised
Solution Approach 1:
The patent uses a balanced approach by adjusting multiple parameters simultaneously: calcium chloride and calcium nitrate for early strength acceleration, triethanolamine for controlled hydration, and sugars for workability maintenance. This multi-parameter optimization achieves early strength enhancement without sacrificing workability or final strength
Solution Approach 2:
The patent incorporates sugars as preliminary action agents that protect the cement paste during early mixing and placement by maintaining workability, while the inorganic and organic accelerators work simultaneously to promote early strength development. This preliminary protection ensures that workability is preserved even as strength enhancement begins
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 admixture significantly enhances early and final compressive strengths, providing increases of up to 20% or more within 1-day, 7-day, and 28-day periods, while maintaining acceptable workability and predictable performance across different cementitious applications.
Implementation Method 1
calcium silicate hydrate... prepared in the presence of a polycarboxylate ether (PCE)... reaction of a water-soluble calcium compound with a water-soluble silicate compound
Implementation Method 2
at least one alkanolamine; at least one inorganic accelerator... desirable early and/or final compressive strengths... increases of up to 20% or more within 1-day, 7-day, and 28-day periods
Data Source
AI summary
A strength enhancing admixture for cementitious and/or pozzolanic compositions including, based on the total dry weight of the admixture, calcium silicate hydrate in an amount of from about 0.5 to about 94 weight percent, and: i) at least one alkanolamine in an amount of from about 0.5 to about 55 weight percent; ii) at least one inorganic accelerator in an amount of from about 0.5 to about 85 weight percent; and iii) at least one carbohydrate in an amount of from about 0.5 to about 50 weight percent; wherein the calcium silicate hydrate includes a product of a reaction of a water-soluble calcium compound with a water-soluble silicate compound in presence of a water-soluble dispersant; and wherein the at least one inorganic accelerator includes any inorganic accelerator(s) other than calcium silicate hydrate.