Ultrafine Particle Grouting Composition with Polycarboxylic Acid Dispersant
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Solution Overview
Problem
Conventional ultrafine particle cement grouting compositions face challenges with injectability and dispersion retainability due to particle aggregation, and existing dispersants like polycarboxylic acid dispersants do not meet the performance requirements for permeability, permeability retainability, and setting characteristics compared to naphthalene dispersants.
Innovation Solution
A polycarboxylic acid copolymer with specific repeating units and a long polyethylene oxide chain is used as a dispersant, combined with a two-step water addition stirring method and high-speed stirring, to create an ultrafine particle grouting composition that suppresses cement particle aggregation and enhances injectability and dispersibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional polycarboxylic acid dispersants are used in ultrafine particle cement grouting compositions, then dispersibility is improved, but permeability, permeability retainability, and setting characteristics deteriorate compared to naphthalene dispersants
Solution Approach 1:
The patent modifies the molecular structure parameters of polycarboxylic acid dispersants by introducing specific side chain structures (polyethylene oxide chains with 2-18 carbon atoms) and controlling the ratio of carboxylic acid groups to hydroxyl groups. These parameter changes enable the dispersant to achieve both excellent dispersibility and maintain permeability and setting characteristics, resolving the contradiction between dispersibility improvement and performance maintenance.
Solution Approach 2:
The patent creates a composite dispersant system combining polycarboxylic acid backbone with polyethylene oxide side chains, forming a graft copolymer structure. This composite structure integrates the dispersing capability of polycarboxylic acid groups with the steric hindrance and solubility enhancement of polyethylene oxide chains, achieving both dispersibility and performance retention simultaneously.
2Ease of operation
If ultrafine particle cement is used to improve injectability, then particle aggregation increases, but dispersibility and dispersion retainability deteriorate
Solution Approach 1:
The patent applies preliminary anti-action by incorporating the modified polycarboxylic acid dispersant into the ultrafine particle cement grouting composition before injection. The dispersant pre-coats the particle surfaces with charged and sterically hindered layers, preventing aggregation during storage and transport, and maintains dispersion stability even under high injection pressure conditions.
Solution Approach 2:
The polycarboxylic acid dispersant acts as an intermediary between ultrafine particle cement and water, facilitating stable dispersion. The dispersant molecules adsorb onto particle surfaces through carboxylic acid groups while their polyethylene oxide side chains extend into the water phase, creating a protective interface that prevents particle aggregation and maintains dispersion retainability during injection and setting.
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 composition achieves improved injectability, dispersibility, and setting characteristics, allowing for effective injection into minute spaces and maintaining performance over time, equivalent to or exceeding that of naphthalene dispersant-containing compositions.
Implementation Method 1
the polycarboxylic acid dispersant...suppresses aggregation of the particles...improve and maintain the performances
Implementation Method 2
a polycarboxylic acid copolymer having a repeating unit derived from an unsaturated polyalkylene glycol monomer and a repeating unit derived from an unsaturated carboxylic acid monomer
Data Source
AI summary
To provide an ultrafine particle grouting composition which is excellent in dispersibility and dispersion retainability and can be easily injected into minute spaces between particles of grounds, rock cracks, and the like. An ultrafine particle grouting composition comprising ultrafine particle cement, wherein the ultrafine particle grouting composition is at least one selected from the group consisting of the following (i) and (ii): (i) the ultrafine particle grouting composition comprises ultrafine particle cement (A) and a polycarboxylic acid dispersant (C), and the ultrafine particle cement (A) comprises blast furnace slag and gypsum, andthe ultrafine particle cement (A) has 10% by volume or less of particles having a particle diameter of 16 μm or more in powder form of the cement; and (ii) the ultrafine particle grouting composition comprises ultrafine particle cement (B) and a polycarboxylic acid dispersant (D), and the ultrafine particle cement (B) comprises 2 to 25% by weight of cement clinker containing 5% by weight or less of 3CaO.Al2O3, 74 to 97% by weight of blast furnace slag, and 1 to 5% by weight of gypsum, and the ultrafine particle cement (B) has 60 to 80% by volume of particles having a particle diameter of 1 to 5 μm in powder form of the cement.