Hydration Control Mixture for Cement Compositions
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Solution Overview
Problem
Dry mortars in the prior art lack satisfactory flowability, compressive strength, and shrinkage properties, leading to reduced open time and unacceptable processability due to rapid aluminate reactions, which are exacerbated by conventional retarders that suppress silicate reactions essential for strength development.
Innovation Solution
A mixture comprising a-hydroxy-carboxylic units, a-hydroxy-sulfonic units, and water-soluble organic carbonates is used as a hydration control additive to regulate the hydration of anhydrous inorganic binders, providing a balanced property profile with extended open time, improved processability, and enhanced compressive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional retarders are added to control aluminate reaction, then open time is extended, but silicate reaction is suppressed which reduces compressive strength development
Solution Approach 1:
The invention divides the hydration control function into two separate components: a retarder (citric acid or gluconic acid) that controls aluminate reaction, and an accelerator (water-soluble organic carbonate) that promotes silicate reaction. This segmentation allows each component to independently manage its specific function without interfering with the other, resolving the contradiction between extending open time and maintaining compressive strength development
Solution Approach 2:
The water-soluble organic carbonate acts as an intermediary substance that mediates between the retarder and the silicate phases. It provides an alkaline environment that protects silicate reactions from suppression by the acid-based retarder, enabling both aluminate retardation and silicate acceleration to occur simultaneously
2Ease of operation
If aluminate-containing components are added to improve flowability and strength, then processability is enhanced, but setting time is significantly reduced
Solution Approach 1:
The retarder components (citric acid or gluconic acid) are added in advance to preemptively control the aluminate reaction rate, creating a delayed setting profile that allows sufficient processing time before the material sets, thereby resolving the contradiction between enhanced processability and extended setting time
3Strength
If rapid aluminate reaction occurs to provide early strength, then strength development is accelerated, but open time is significantly reduced
Solution Approach 1:
The invention segments the strength development mechanism into two independent pathways: aluminate-based early strength (controlled by retarder) and silicate-based later strength (accelerated by organic carbonate). This allows early strength to be achieved without sacrificing open time, as the silicate reaction is now independently accelerated
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 proposed mixture effectively retards the hydration of aluminate-containing cements, ensuring sufficient open time for processing while accelerating setting, resulting in improved compressive strength and a well-balanced property profile compared to conventional retarders.
Implementation Method 1
the hydration control mixture effectively retards the hydration of aluminate-containing cements
Implementation Method 2
accelerating setting, resulting in improved compressive strength
Data Source
AI summary
The present invention relates to a mixture comprising at least one compound comprising an α-hydroxy-carboxylic unit, α-hydroxy-sulfonic acid unitor α-carbonyl-carboxylic unit and at least one water-soluble organic carbonate. The mixture is useful as a hydration control agent in construction chemical compositions comprising an inorganic binder.