Sugar Acid Additive for Construction Chemical Compositions
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Solution Overview
Problem
Dry mortars based on calcium sulfate hemihydrate, anhydrite, or aluminate-containing cements face issues with flowability and compressive strength development, leading to reduced open time and unacceptable processability due to rapid gypsum formation or aluminate reaction, and conventional retarders compromise strength development while improving workability.
Innovation Solution
An additive comprising an amide or ester of a sugar acid combined with a water-soluble comb polymer, which retards the hardening of construction chemical compositions by influencing gypsum formation and aluminate reactions, maintaining mechanical strength and improving slump retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional retarders are used to improve workability and extend open time, then processability is improved, but compressive strength development is compromised
Solution Approach 1:
The invention uses a composite additive system combining a sugar acid derivative (retarder component) with a polycarboxylate ether (dispersant and strength-enhancing component). This composite approach allows the retarder to extend open time while the polycarboxylate ether maintains particle dispersion and prevents strength loss, resolving the contradiction between workability improvement and strength preservation
Solution Approach 2:
The polycarboxylate ether acts as an intermediary substance that mediates between the retarder's slowing effect on hydration and the need for strength development. It maintains effective particle dispersion and interfacial bonding during the extended setting time, ensuring that strength development is not compromised despite the retarded hydration process
2Ease of operation
If mixing water is increased to improve flowability, then processability is improved, but mechanical strength and resistance deteriorate due to excess voids
Solution Approach 1:
The invention changes the chemical parameters of the mixing water by adding the additive system, which modifies the hydration kinetics and particle interaction mechanisms. This allows achieving improved flowability through chemical modification rather than increasing water quantity, thereby avoiding the formation of excess voids and maintaining mechanical strength
3Speed
If rapid gypsum formation occurs to achieve quick setting, then hardening speed is improved, but open time and processability are reduced
Solution Approach 1:
The additive system creates a staged hydration process where the sugar acid derivative initially retards gypsum formation to extend open time, then gradually allows controlled hydration to proceed. This periodic control of reaction rate ensures both extended processability and eventual quick setting, resolving the contradiction between hardening speed and open time
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 enhances slump retention, reduces temperature-dependent fluidity issues, and maintains or exceeds the compressive strength achieved with conventional retarders, ensuring improved processability without compromising mechanical properties.
Implementation Method 1
retards the hardening of a construction chemical composition by influencing gypsum formation and aluminate reactions
Implementation Method 2
retards the hardening of a construction chemical composition by influencing gypsum formation and aluminate reactions
Data Source
Figure 1~2
AI summary
The present invention concerns an additive for construction chemical compositions, in particular mortar and cement compositions. The additive comprises at least one amide or ester of a sugar acid and at least one water-soluble comb polymer which contains, on the main chain, acid functions and side chains having ether functions. The additive is useful for retarding the hardening of a construction chemical composition.