Dry Grout Capsule for Rapid Anchoring
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Solution Overview
Problem
Current anchoring systems for reinforcing and anchoring elements in substrates face issues such as rapid setting calcium aluminate cement not being accepted for structural applications in certain regions, toxicity and flammability of resin-based materials, and corrosion of mechanical anchors, along with chromium(VI) compounds in cement posing health risks.
Innovation Solution
A dry grout composition comprising calcium aluminosulfate based hydraulic cement, mineral filler, thixotropic agent, superplasticizer, and air entraining agent, optionally including flyash or silica fume, and a chromium(VI)-reducing agent, encapsulated in a water-permeable capsule made of unwoven polyester, which reduces alumina content and incorporates a chromium(VI)-reducing agent to minimize toxicity and enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wet grout is used for anchoring reinforcing bars, then the grout can be easily pumped and placed, but the grout requires additional curing time before the reinforcing bar can be loaded
Solution Approach 1:
The patent changes the physical state parameter of the grout from liquid (wet) to solid (dry) form. The dry grout composition is pumped as a free-flowing powder mixture and then transformed into a hardened state through mixing with water and chemical reaction, eliminating the need for extended curing time while maintaining ease of placement
Solution Approach 2:
The grout undergoes phase transition from dry powder to hardened matrix through controlled chemical reaction. The anhydrite-based binder reacts with water to form a rigid structure, providing immediate load-bearing capacity without requiring prolonged curing periods associated with traditional cement-based grouts
2Strength
If traditional cement-based grout is used, then the grout provides good bonding strength, but the grout is susceptible to freeze-thaw damage and chemical attack
Solution Approach 1:
The patent uses a composite binder system combining anhydrite (calcium sulfate) with supplementary cementitious materials such as fly ash, silica fume, or metakaolin. This composite composition provides bonding strength comparable to or exceeding traditional cement grout while offering superior resistance to freeze-thaw cycling and chemical attack due to the low permeability and chemically inert nature of the anhydrite matrix
Solution Approach 2:
The patent changes the chemical composition parameter by replacing Portland cement with anhydrite-based binder. This fundamental material substitution alters the grout's chemical properties to be less susceptible to sulfite attack and freeze-thaw damage while maintaining or improving bonding strength through optimized mix proportions and supplementary materials
3Loss of time
If rapid-setting grout is used to reduce curing time, then the grout sets quickly, but the grout requires precise water-to-powder ratio control and has limited working time
Solution Approach 1:
The dry grout composition is designed to self-regulate the mixing process. The free-flowing powder mixture automatically achieves uniform distribution when combined with water, and the anhydrite-based binder provides consistent setting characteristics without requiring precise water-to-powder ratio control. This self-service特性 eliminates the need for exact metric measurements while maintaining rapid setting properties
Solution Approach 2:
The patent modifies the setting time parameter by using anhydrite as the primary binder, which naturally provides rapid setting characteristics. Simultaneously, the granular composition and free-flowing properties are optimized to extend working time during placement, creating a balanced system that achieves both rapid curing and ease of operation
4Loss of time
If dry grout composition is designed for rapid setting, then the grout reduces curing time, but the grout composition becomes complex with multiple components
Solution Approach 1:
The anhydrite-based binder serves multiple functions simultaneously: it provides rapid setting, develops high early strength, offers resistance to freeze-thaw and chemical attack, and enables free-flowing powder characteristics. This multi-functional binder reduces the need for numerous separate additives and components, simplifying the overall composition while achieving rapid curing performance
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 provides improved anchoring performance with reduced alumina content, enhanced durability, and reduced chromium(VI) toxicity, ensuring effective bonding and resistance to corrosion, while being environmentally safer and suitable for various substrates and conditions.
Implementation Method 1
A dry grout composition includes a binder based on anhydrite that has been mixed with water to form a rigid matrix
Implementation Method 2
The capsule is designed to dissolve in water to release the dry grout composition
Data Source
Figure 1~2
Figure 3~5
AI summary
The present invention relates to a dry grout composition comprising a calcium aluminosulfate based hydraulic cement, a mineral filler, a thixotropic agent, and a superplasticizer agent. An anchoring capsule, containing the dry grout composition, for use in anchoring reinforcing member dowel, or anchor elements in a hole of a substrate, and a method of use is also provided.