Macro-Cement Coating for UHPC Particle Dispersion
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Solution Overview
Problem
Current methods for producing ultra-high performance concrete (UHPC) face challenges in achieving uniform distribution of silica fume and nano-particles due to aggregation, leading to reduced strength and durability, and existing mixing technologies fail to provide optimal homogenization and shelf life of cementitious materials.
Innovation Solution
A multicomponent macro-cement composition is developed, comprising micron-sized cementitious materials coated or loaded with submicron or nano-sized supplemental cementitious materials, along with pozzolanic materials and reinforcement fibers, using a multi-stage homogenization process that includes high-energy mixing and mechanical activation to achieve uniform distribution and enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silica fume and nano-particles are added to cementitious materials to improve packing density and strength, then the compressive strength and durability are enhanced, but particle aggregation occurs leading to non-uniform distribution
Solution Approach 1:
The patent applies preliminary action by pre-coating silica fume and nano-particles onto cementitious carrier particles before final mixing. This pre-attachment prevents aggregation during storage and handling, ensuring uniform distribution when the macro-cement is later used in concrete applications.
Solution Approach 2:
The patent uses an intermediary approach by employing carrier particles (cementitious materials) as intermediaries to hold and distribute the silica fume and nano-particles. These carriers act as mediators that prevent direct aggregation of fine particles while maintaining their beneficial effects on strength and durability.
2Manufacturing precision
If high-energy mixing is used to achieve uniform particle distribution, then homogenization is improved, but particle aggregation may increase due to mechanical activation
Solution Approach 1:
The patent applies preliminary action by pre-attaching particles through coating before high-energy mixing occurs. This pre-bonding prevents aggregation during subsequent mechanical activation and mixing processes, maintaining stability throughout the concrete production cycle.
Solution Approach 2:
The patent applies parameter changes by controlling the energy input at different stages - using lower energy during coating to prevent aggregation, then allowing higher energy mixing later to achieve homogenization without disrupting the pre-formed particle attachments.
3Duration of action of stationary object
If multi-stage homogenization process is implemented to improve shelf life and uniformity, then process complexity increases, but production time and energy consumption increase
Solution Approach 1:
The patent applies preliminary action by performing particle coating and attachment during the cement manufacturing process itself, before the macro-cement is stored or shipped. This eliminates the need for separate pre-mixing stages later, reducing overall production time while extending shelf life through stable pre-formed structures.
Solution Approach 2:
The patent merges the coating process with the existing cement manufacturing process, combining what would otherwise be separate operations into a single integrated workflow. This reduces total process time and energy consumption while achieving the benefits of multi-stage homogenization.
4Quantity of substance
If micron-sized cementitious particles are used as carriers, then packing density is improved, but handling and dust generation become more difficult
Solution Approach 1:
The patent applies this principle by forming a coating layer (thin film) of silica fume and nano-particles on the carrier particles. This coating acts as a protective shell that reduces dust generation during handling while maintaining the high packing density benefits of the fine particles.
Solution Approach 2:
The patent creates composite macro-cement particles combining cementitious carriers with silica fume and nano-particle coatings. This composite structure maintains high packing density while the coated surface reduces dust generation and improves handling characteristics compared to bare fine particles.
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 results in improved packing density, increased strength, extended shelf life, and enhanced workability of UHPC, overcoming aggregation issues and optimizing the distribution of particles, leading to superior mechanical properties and reduced dust handling hazards.
Implementation Method 1
The multi-stage homogenization process is characterized in that the macro-cement is homogenized in water at high energy levels, in subsequent process steps homogenized as a mixture at lower energy levels
Implementation Method 2
utilizing a multi-stage process involving mechanical activation and homogenization of the macro-cement at various energy levels
Implementation Method 3
comprising micron-sized cementitious materials coated or loaded with submicron or nano-sized supplemental cementitious materials
Data Source
AI summary
A macro-cement and associated methods useful for preparing pastes, mortars, concretes and other cement-based materials having high workability, high density, and high strength are disclosed. A method of producing a macro-cement includes cement, supplemental cementitious materials (SCM's), including siliceous submicron-sized particles and nano-sized particles, and polymers in the form of liquid or dry chemical admixtures for concrete. The cement mixture may be used for making ultra-high performance concrete (UHPC).