Composite Cementitious Discrete-Element Feedstock for 3D Printing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing concrete 3D printing systems face challenges with controlling the viscosity and curing of wet concrete slurry, leading to issues like thermal runaway, clogging, and complex mixing procedures, which can result in structural weaknesses and inefficiencies in construction processes.
Innovation Solution
A composite cementitious material composed of discrete elements with mineral rock agglutinates, super absorbent polymer particles, and cement particles, cohered by a binder that dissolves upon activation, allowing for dry transportation and on-site hydration with water or electromagnetic energy, simplifying the handling and application process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wet Portland cement concrete slurry is pre-mixed and pumped through hoses to a print head nozzle, then continuous concrete application can be achieved, but the system suffers from thermal runaway issues, viscosity control difficulties, and clogging problems
Solution Approach 1:
The concrete mixture is segmented into discrete elements (pellets or nodules) rather than being pumped as continuous wet slurry. Each discrete element contains cement particles, aggregate, and superabsorbent polymer particles encapsulated in a binder, allowing them to be conveyed individually through the printing system without the thermal runaway and viscosity issues of continuous slurry
Solution Approach 2:
The invention changes the physical state parameter of the concrete from wet slurry to dry discrete elements. By transforming the concrete into discrete elements with controlled moisture content and encapsulating the superabsorbent polymer particles within them, the system eliminates thermal runaway while maintaining the ability to be pumped and extruded
2Ease of operation
If wet concrete slurry is used in 3D printing systems, then concrete can be extruded to form additive layers, but extensive cleaning operations are required and the system cannot be turned on and off as needed
Solution Approach 1:
The concrete is transformed from wet slurry to dry discrete elements, changing the moisture parameter. This allows the printing system to handle free-flowing discrete elements that can be easily loaded and unloaded without the clogging and cleaning issues associated with wet concrete, enabling the system to be turned on and off as needed
Solution Approach 2:
The discrete elements are designed as single-use units that can be easily disposed of after application. The dry discrete elements can be quickly cleared from the printing system without extensive cleaning operations, as they do not harden and clog the system like wet concrete would
3Strength
If complex procedures are used to control material mix, rheology, and consistency, then concrete structural strength can be maintained, but the process becomes difficult and time-consuming
Solution Approach 1:
The concrete mixture is segmented into discrete elements with pre-determined compositions. Each element contains cement particles, aggregate, and superabsorbent polymer particles in controlled proportions, eliminating the need for complex real-time mixing procedures while ensuring consistent structural strength
Solution Approach 2:
The discrete elements are prepared in advance with the correct material composition and ratios of cement, aggregate, and superabsorbent polymer. This preliminary preparation of discrete elements with controlled rheology eliminates the need for complex on-site mixing procedures
4Productivity
If pre-mixed wet concrete slurry is transported and stored, then concrete can be applied continuously, but the mixture must be maintained at correct viscosity and is prone to slumping and crumbling
Solution Approach 1:
The concrete is transformed from wet slurry to dry discrete elements, changing the moisture content parameter. The discrete elements can be transported and stored in a stable dry state without viscosity issues, then activated by adding water at the application point to restore the concrete's working properties
Solution Approach 2:
By segmenting the concrete into discrete elements with encapsulated superabsorbent polymer particles, the system eliminates the viscosity stability issues of continuous wet slurry. Each discrete element maintains its composition independently, preventing slumping and crumbling during transport and storage
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 solution enables more controlled and efficient concrete construction by eliminating the need for pre-mixed wet slurry, reducing logistical challenges, and ensuring consistent hydration, resulting in improved structural integrity and reduced operational complexities in 3D printing processes.
Implementation Method 1
Super absorbent polymer (SAP) particles are disposed on the irregular surface regions and in the cavities
Implementation Method 2
The addition of water initiates a hydration process that causes an exothermic chemical reaction that ultimately results in the curing and hardening of the concrete material
Implementation Method 3
The addition of water initiates a hydration process that causes an exothermic chemical reaction
Implementation Method 4
A binder is provided to cohere the agglutinates, SAP particles, and cement particles
Data Source
AI summary
A composite cementitious feedstock comprises discrete elements. Each discrete element includes mineral rock agglutinates having irregular surface regions and cavities. Super absorbent polymer (SAP) particles and cement particles are disposed on the irregular surface regions and in the cavities. A binder coheres the agglutinates, SAP particles, and cement particles.