Fiber-Reinforced Mineral Binder Application Method
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Solution Overview
Problem
Current 3D printing methods for cementitious materials face challenges such as slow strength development, air inclusions, inhomogeneity, and fiber clumping, which lead to defects and interruptions in the printing process.
Innovation Solution
A method involving the separation of steps for preparing a water-containing mineral binder composition and mixing an aqueous accelerator, using a continuous mixer with dynamic elements to ensure even distribution and prevent fiber agglomeration, allowing for uninterrupted and homogeneous application of fiber-containing mineral binder compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If water is removed from concrete by vacuum before application, then the material becomes rigid and self-supporting, but the installation becomes expensive, complex and the weight of the print head increases
Solution Approach 1:
The patent extracts the water removal function from the print head system by using a separate vacuum station located away from the print head. This allows the concrete to be pre-dewatered before application, achieving dimensional stability without adding complexity to the printing system itself.
Solution Approach 2:
The process is segmented into separate stages: concrete preparation with controlled water content, transport to the printing location, and then application. This segmentation allows each stage to be optimized independently, avoiding the need for complex integrated systems.
2Strength
If fibers are added to improve cohesion and strength, then the material properties improve, but the fibers clump together and clog conveying lines
Solution Approach 1:
Fibers are pre-distributed into the concrete mixture at the ready-mixed concrete plant before transport. This preliminary action ensures uniform fiber distribution throughout the mixture, preventing clumping during conveying and application.
Solution Approach 2:
The patent specifies optimal fiber content ranges (0.4-25 liters per cubic meter) and fiber characteristics (length, diameter, material properties) to balance the benefits of fiber reinforcement with the need to maintain flowability and prevent clogging during conveying.
3Strength
If fibers are added to improve layer bonding and crack resistance, then the structural properties improve, but the fibers orient in one direction which limits their effectiveness
Solution Approach 1:
The patent employs vibration during the application process to randomize fiber orientation. The vibrational energy disrupts fiber alignment that would otherwise occur due to flow direction, ensuring fibers are distributed in multiple orientations for optimal structural performance in all directions.
4Speed
If cement mixture is made very stiff with little water to achieve rapid strength development, then strength development improves, but the mixture can only be conveyed over short distances with high pump pressure and contains defects
Solution Approach 1:
The concrete is pre-mixed with optimized water content and fiber distribution at a ready-mixed plant before transport. This allows the mixture to maintain workability during conveying while achieving the desired strength development characteristics upon application.
Solution Approach 2:
The patent specifies optimal water content ranges and fiber dosages that balance the need for rapid strength development with the requirement for adequate flowability during conveying and application, preventing both excessive stiffness and material segregation.
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
This approach enables rapid, reliable, and aesthetically pleasing application of fiber-containing mineral binder compositions, ensuring strong, uniform, and crack-resistant layers without interruptions, suitable for large-scale production.
Implementation Method 1
mixing of the aqueous accelerator with the water-containing binder composition takes place in a continuous mixer
Implementation Method 2
Cement achieves its strength by reacting with water in a chemical process known as cement hydration
Data Source
Figure 1
AI summary
The present invention relates to a method for the application of hydrous mineral binder compositions which contain fibres. An aqueous accelerator is mixed with the aqueous binder composition in a mixer shortly before the application. The method according to the invention is very robust and makes it possible to quickly produce even large moulded bodies having a uniform surface and very good strength development properties.