SAP-Defoamer Admixture for Mineral Binder Shrinkage Control
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Solution Overview
Problem
Existing methods for reducing shrinkage in mineral binder compositions, such as cementitious binders, are often expensive, complicated, or have limited effectiveness, leading to issues like cracking and reduced dimensional stability.
Innovation Solution
An admixture comprising a super absorbent polymer (SAP) and a defoamer is used to reduce shrinkage in mineral binder compositions without affecting workability, setting behavior, or strength development, providing improved dimensional stability and surface texture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If previously known shrinkage reducers are used, then shrinkage reduction effectiveness is limited, but cost and complexity increase
Solution Approach 1:
The patent combines superabsorbent polymer (SAP) particles with a defoamer in a single admixture composition. The SAP provides shrinkage reduction through internal curing by absorbing and releasing water, while the defoamer eliminates air bubbles that would otherwise create voids and reduce effectiveness. This merging of two functional components into one admixture achieves superior shrinkage control without requiring separate addition steps.
Solution Approach 2:
The invention creates a composite admixture material consisting of SAP particles coated or combined with defoamer substances. This composite structure allows the defoamer to be distributed uniformly on or within the SAP particles, ensuring that when the SAP absorbs water and swells, the defoamer simultaneously prevents bubble formation in the saturated regions. The composite nature enhances overall performance beyond what either component could achieve alone.
2Stability of the object's composition
If surface wetting or covering is performed to prevent drying, then dimensional stability improves, but production process complexity increases
Solution Approach 1:
The SAP-containing admixture enables the concrete to perform its own internal curing without external intervention. The SAP particles absorb excess water during mixing, then gradually release it during hardening and drying phases, automatically compensating for moisture loss and preventing shrinkage cracks. This self-regulating mechanism eliminates the need for manual surface wetting or covering operations, simplifying the production process while maintaining dimensional stability.
Solution Approach 2:
The SAP particles are pre-loaded with water absorption capacity during the mixing stage. They absorb and store water in advance, then release it progressively as needed during subsequent drying periods. This preliminary water storage action prepares the concrete internally to withstand future moisture loss, preventing shrinkage before it occurs without requiring later corrective measures like surface covering.
3Reliability
If shrinkage reduction additives are added, then cracking is reduced, but workability and setting behavior are affected
Solution Approach 1:
The invention carefully controls the particle size distribution, absorption capacity, and chemical composition parameters of the SAP particles to minimize their impact on workability. By selecting appropriate SAP parameters (particle size 0.06-2.0 mm, controlled absorption ratios), the admixture provides shrinkage protection while maintaining concrete flowability and setting characteristics. The defoamer component further refines the mixture homogeneity, ensuring uniform distribution without clumping that would affect workability.
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 effectively reduces shrinkage and cracking, ensuring smoother surfaces and simplified production processes by eliminating the need for surface wetting or covering, while maintaining strength development.
Implementation Method 1
an admixture for mineral binder compositions, in particular a shrinkage reducing admixture for mineral binder compositions, comprising at least one super absorbing polymer SAP
Implementation Method 2
comprising at least one super absorbing polymer SAP and at least one defoamer D
Data Source
AI summary
An additive, in particular a shrinkage reducing agent, for mineral binder compositions including at least one super absorbent polymer SAP and at least one defoamer D. Further, a mineral binder composition including the additive, processes and methods for the mixing thereof, and to hardened articles obtainable therefrom.