Multifunctional Superplasticizer for Ultra-High Performance Concrete
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Solution Overview
Problem
Conventional water reducing agents fail to effectively disperse ultra-fine particles in ultra-high performance concrete, resulting in poor fluidity and high viscosity, which complicates construction due to weak adsorption on nanoparticles and insufficient surface coverage.
Innovation Solution
A multi-functional group superplasticizer with a backbone of alkyl chains and side chains containing carboxylic acid, carboxylate, polyether, and polyol amine groups substituted with phosphoric acid or phosphite, enhancing adsorption ability and reducing particle friction, is developed through copolymerization of terminal alkenylamine, polyhydroxyaldehyde, and phosphorous-containing composition, followed by free radical polymerization with unsaturated carboxylic acid and polyether.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional polycarboxylate superplasticizer is used in ultra-high performance concrete, then the concrete structure is maintained, but the fluidity is poor and viscosity is high due to insufficient adsorption on ultra-fine particles
Solution Approach 1:
The patent applies local quality by creating different functional regions on the polymer molecule: the backbone provides structural support while side chains with carboxyl groups specifically target ultra-fine particles for adsorption. This localized functional differentiation enables the superplasticizer to simultaneously maintain concrete structure and improve fluidity by preferentially adsorbing on nanoparticle surfaces.
Solution Approach 2:
The patent uses composite materials by combining multiple functional groups (carboxyl, carboxylate, polyether, polyol amine with phosphoric acid or phosphite) into a single superplasticizer molecule. This composite structure provides both strong adsorption capability for ultra-fine particles and adequate steric hindrance for cement particles, resolving the contradiction between adsorption affinity and fluidity.
2Strength
If ultra-fine powder content is increased to achieve ultra-high performance concrete, then compressive strength reaches 100 MPa or more, but viscosity increases and construction becomes difficult
Solution Approach 1:
The patent introduces the multi-functional group superplasticizer as an intermediary substance that mediates between ultra-fine particles and water. The superplasticizer adsorbs on nanoparticle surfaces, creating a lubricating layer that reduces inter-particle friction and lowers viscosity, thereby enabling construction of high-strength concrete with 30-40% ultra-fine powder content.
Solution Approach 2:
The patent applies parameter changes by modifying the chemical composition and molecular structure of the superplasticizer to include multiple functional groups with different adsorption characteristics. This enables the superplasticizer to effectively interact with ultra-fine particles at the nanoscale, changing the rheological parameters of the concrete mixture to achieve lower viscosity while maintaining high strength.
3Strength
If water-binder ratio is reduced to achieve ultra-high performance concrete, then strength increases, but fluidity deteriorates and workability becomes poor
Solution Approach 1:
The patent uses parameter changes by developing a superplasticizer with optimized molecular parameters including side chain length, functional group density, and backbone structure. These parameter optimizations enable the superplasticizer to maintain effective adsorption and steric hindrance functions even at ultra-low water-binder ratios, preserving fluidity while achieving high strength.
Solution Approach 2:
The patent applies universality by designing a multi-functional superplasticizer that simultaneously performs multiple functions: adsorption on ultra-fine particles, steric hindrance for cement particles, water retention, and viscosity reduction. This multi-functionality allows the concrete to achieve high strength at low water-binder ratio while maintaining adequate fluidity and workability.
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 superplasticizer significantly improves the fluidity and reduces viscosity of ultra-high performance concrete, achieving better dispersion and reducing shear viscosity by 17-42% compared to commercial polycarboxylate superplasticizers, while requiring a lower dosage, effectively addressing the limitations of conventional agents.
Implementation Method 1
adsorbed thereon through electrostatic interaction between the charged functional group and surface of cement particles
Implementation Method 2
corresponding long side chain prevents the cement particles from coming close to each other and agglomerating through steric hindrance (repulsion action)
Implementation Method 3
releasing the enclosed moisture, improving workability of the concrete, and reducing water-cement ratio
Data Source
AI summary
Providing a multi-functional group superplasticizer for an ultra-high performance concrete and a method for preparing the same. Its backbone is an alkyl chain, and its side chain are some side chains with carboxylic acid or carboxylate at terminals, some polyether side chains, and some polyol amine side chains substituted with phosphoric acid or phosphite at terminals, the polyol amine side chains substituted with phosphoric acid or phosphite at terminals is connected to the backbone through a phenyl or an alkyl group of 1-9 carbons, and a ratio of a number of the side chains with carboxylic acid or carboxylate at terminals to a total number of side chains is ≥0 and ≤0.8; and a ratio of a number of the polyether side chains to the total number of side chains is ≥0.1 and ≤0.9.