Dry Cementitious Mixture for 3D Printing
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Solution Overview
Problem
Existing 3D printing technologies for construction materials face challenges with hydraulic binders having short initial setting times, leading to material buildup in mixing devices and deposition heads, limited operational flexibility, and inadequate bonding strength between layers, which complicates the printing process and increases costs.
Innovation Solution
A dry cementitious material mixture comprising hydraulic cement, viscosity-enhancing admixtures, and accelerators, formulated to provide a consistent and stable flowable construction material that can be mixed with water, eliminating the need for on-site mixing and admixture addition at the deposition head, ensuring mechanical stability and adequate bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a hydraulic binder with a short initial setting time is used, then the mechanical stability of deposited layers is improved, but material buildup in mixing devices and deposition heads occurs
Solution Approach 1:
The patent pre-mixes the viscosity-enhancing admixture with the hydraulic binder in a dry state before use. This preliminary action ensures that the admixture is uniformly distributed and immediately active when water is added, providing instant viscosity enhancement that prevents material buildup while maintaining mechanical stability of deposited layers.
Solution Approach 2:
The patent changes the physical-chemical parameters of the binder by incorporating a viscosity-enhancing admixture (such as cellulose ethers or starch derivatives) that modifies the rheological properties. This parameter change allows the material to maintain appropriate viscosity during pumping and deposition, preventing buildup while still achieving rapid setting for mechanical stability.
2Productivity
If a hydraulic binder with a short initial setting time is used, then the printing speed is improved, but the operational flexibility is limited
Solution Approach 1:
The viscosity-enhancing admixture is pre-incorporated into the dry binder mixture, creating a material that is ready for immediate use with consistent rheological properties. This preliminary preparation eliminates the need for on-site mixing adjustments, maintaining high printing speed while providing operational flexibility through predictable material behavior that can be reliably processed.
Solution Approach 2:
The pre-mixed dry binder with integrated viscosity-enhancing admixture is a self-sufficient material that requires only water addition before use. It automatically provides the necessary viscosity characteristics without requiring additional on-site mixing operations or adjustments, thus maintaining printing speed while enhancing operational flexibility.
3Adaptability or versatility
If a hydraulic binder with a long initial setting time is used, then the operational flexibility is improved, but the bonding strength between layers is reduced
Solution Approach 1:
The patent modifies the rheological parameters of the binder by adding a viscosity-enhancing admixture that increases viscosity immediately upon water addition. This parameter change allows the material to maintain stable, pumpable consistency during handling while the hydraulic binder itself sets rapidly, ensuring strong interlayer bonding without sacrificing operational flexibility.
4Ease of operation
If the construction material has low viscosity for good pumpability, then the ease of operation is improved, but the mechanical stability of deposited layers is reduced
Solution Approach 1:
The viscosity-enhancing admixture is pre-mixed with the hydraulic binder in dry state, creating a uniform distribution that activates immediately upon water addition. This preliminary action ensures that the material achieves the right balance of viscosity for pumpability while simultaneously providing the structural stability needed for deposited layers, eliminating the need to choose between the two properties.
Solution Approach 2:
The patent creates a composite binder system combining the hydraulic binder with a viscosity-enhancing admixture (such as cellulose ether or starch derivative). This composite material exhibits dual characteristics: it remains sufficiently fluid for pumpability while developing rapid mechanical stability once deposited, resolving the contradiction between ease of operation and structural integrity.
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 solution enables continuous, high-speed 3D printing with improved mechanical stability and bonding strength between layers, reducing material buildup and operational complexity, while providing cost savings and consistent quality through a single, easy-to-use dry mixture.
Implementation Method 1
a viscosity-enhancing admixture, wherein the at least one viscosity-enhancing admixture is present in an amount of 0.05-1.5% by weight, preferably 0.2-0.6% by weight, based on the hydraulic cement
Implementation Method 2
at least one setting accelerator, wherein the at least one setting accelerator is present in an amount of 0.5-6.0% by weight, preferably 1.5-4.0% by weight, based on the hydraulic cement
Implementation Method 3
a hydraulic cement
Data Source
AI summary
A dry cementitious material mixture for 3D-printing, includes a hydraulic cement, at least one viscosity enhancing admixture, at least one accelerator and aggregates, wherein the at least one viscosity enhancing admixture is present in an amount of 0.05-1.5% by weight based on the hydraulic cement and the at least one accelerator is present in an amount of 0.5-6.0% by weight based on the hydraulic cement.