Extruded Cement-Based Materials with Rheology Modifiers
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Solution Overview
Problem
Cement-based materials are typically too wet to be extruded effectively due to high water content, limiting their application in forming lightweight, high-strength composites.
Innovation Solution
A mixture of cement, water, gypsum, secondary materials, reinforcement fibers, and a rheology modifying agent is used, allowing the cement-based material to be extruded and cured, with the addition of a retarder to extend the extrusion time, resulting in a lightweight material with specific strength ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high water content is used in cement-based materials to improve workability, then the material becomes too wet to be extruded effectively, but reducing water content limits application in forming lightweight composites
Solution Approach 1:
The patent changes the rheological parameters of the cement-based material by adding specific additives (polycarboxylate superplasticizer, cellulose ether, and hydrocolloid) that modify the flow and setting characteristics. This allows the material to maintain workability at lower water-cement ratios (0.25-0.40) while becoming extrudable through controlled viscosity modification during processing
Solution Approach 2:
The patent introduces rheology-modifying agents as intermediaries between the cement paste and water. These additives (superplasticizers, cellulose ethers, hydrocolloids) act as mediators that enable extrusion by controlling the flow behavior and setting time of the cement-based material without requiring high water content
2Productivity
If conventional cement-based materials are used, then they can be produced with standard water content, but they are too wet to extrude and cannot form lightweight high-strength composites
Solution Approach 1:
The patent creates a composite cement-based material system combining cement, gypsum, secondary materials (sand, fly ash, slag), reinforcement fibers, and multiple rheology-modifying agents. This composite approach enables both extrusion processability and final product strength while achieving lightweight properties through optimized material composition
Solution Approach 2:
The patent modifies key parameters including water-cement ratio (0.25-0.40), additive concentrations (superplasticizer 0.5-5.0%, cellulose ether 0.1-1.0%, hydrocolloid 0.1-0.5%), and secondary material content to achieve the desired balance between extrusion capability and final product performance
3Shape
If the cement mixture is made extrudable by adding rheology modifying agents, then the material can be formed into desired shapes, but the setting time and extrusion time must be extended
Solution Approach 1:
The patent uses a combination of additives with different setting modification effects to create a staged setting behavior. The superplasticizer provides initial workability extension, while cellulose ether and hydrocolloid contribute to prolonged setting control, enabling extended extrusion time without compromising final strength development
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 process enables the production of a lightweight cement-based material with a density of 1.4 to 2.4 g/cm3, compressive strength of 5 to 100 MPa, and flexural strength of 5 to 35 MPa, reducing shrinkage cracks and enhancing toughness, while allowing for flexible shaping and curing.
Implementation Method 1
a rheology modifying agent in the range of about 0.5 to 10% by wet weight percent
Implementation Method 2
allowing the extruded mixture to set
Data Source
AI summary
An extrudable cement-based material formed from a mixture that includes cement, water, gypsum, secondary materials, reinforcement fibers and rheology modifying agent. The extrudable cement-based material is a lightweight material that has a density in the range of about 1.4 to 2.4 g/cm3, a compressive strength in the range of about 5 to 100 MPa, and a flexural strength in the range of about 5 to 35 MPa. Note that the cement may contain gypsum such that the gypsum is not added to the mixture.