Batch Casting High-Fluidity and Low-Fluidity Concrete for Bridge Decks
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Solution Overview
Problem
Current methods for casting high-performance concrete on bridge structures with slope gradients face challenges in maintaining fluidity and workability, leading to increased construction costs, reduced durability, and difficulties in achieving desired shapes, particularly with high-fluidity concrete which flows excessively and requires separate formwork for inclined surfaces.
Innovation Solution
A method of batch-casting high-fluidity and low-fluidity high-performance concrete using a concrete casting apparatus, where the amount of superplasticizer is maintained constant, and additives like cellulose derivatives or air entraining agents are used to control fluidity and workability, allowing for efficient casting of girder and deck plate portions with slope gradients without separate formwork.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high-performance concrete with high fluidity is used to improve workability and self-compaction, then constructability is improved, but the concrete flows excessively on inclined surfaces and cannot maintain the required shape
Solution Approach 1:
The patent adjusts the water-to-binder ratio and superplasticizer dosage to control concrete fluidity parameters, creating two distinct mixes: one with higher fluidity for horizontal surfaces and another with lower fluidity for inclined surfaces, thereby resolving the contradiction between workability and shape retention
Solution Approach 2:
The patent applies different concrete mixes with different fluidity characteristics to different locations: high-fluidity concrete for girder portions and low-fluidity concrete for deck plate portions with slope gradients, allowing each location to have the optimal fluidity for its specific casting requirements
2Shape
If upper formwork is used to prevent concrete flow on inclined surfaces, then shape retention is improved, but closed air and foam are generated, deteriorating appearance and durability
Solution Approach 1:
The patent changes the fluidity parameter of the concrete mix itself rather than relying on formwork constraints, using a lower water-to-binder ratio and reduced superplasticizer dosage to create concrete with appropriate viscosity that maintains shape without requiring upper formwork
Solution Approach 2:
The patent uses a viscosity-modifying agent as an intermediary substance that adjusts the rheological properties of the concrete, allowing it to maintain shape on inclined surfaces without the harmful effects of upper formwork while preserving durability
3Reliability
If high-performance concrete with low water-to-binder ratio is used to improve durability, then durability is improved, but fluidity is reduced making it difficult to achieve required shapes
Solution Approach 1:
The patent systematically adjusts multiple parameters including water-to-binder ratio, superplasticizer dosage, and viscosity-modifying agent content to achieve the optimal balance between durability and fluidity, creating concrete mixes that satisfy both requirements simultaneously
Solution Approach 2:
The patent uses composite chemical admixtures including superplasticizers and viscosity-modifying agents in combination with high-performance concrete materials, creating a composite system that provides both high durability through low water-to-binder ratio and adequate fluidity through the synergistic effects of the admixtures
4Ease of operation
If separate casting of high-fluidity and low-fluidity concrete is performed to achieve different fluidity requirements, then workability is improved, but construction time and cost increase
Solution Approach 1:
The patent combines the casting of high-fluidity and low-fluidity concrete into a single batch operation using a concrete mixer truck with separate charging ports, allowing both types of concrete to be prepared and cast simultaneously, thereby reducing construction time and cost while maintaining the required workability differences
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
This approach reduces construction costs and time, enhances durability by preventing cold joints, and ensures consistent workability across different fluidity levels, improving the overall lifespan of bridge structures.
Implementation Method 1
due to having a low water-to-binder ratio and using a large amount of binder, the high performance (or ultra-high performance) concrete has a characteristic of having fluidity that allows it to flow like water by using a large amount of superplasticizer
Implementation Method 2
forming the high-fluidity high performance concrete with adjusted fluidity by using a thickener
Implementation Method 3
an air entraining agent, and/or an alginate foaming agent
Data Source
AI summary
A method of batch-casting high-fluidity high performance concrete and low-fluidity high performance concrete, wherein the method is capable of batch-casting high-fluidity high performance concrete for forming a girder portion of a bridge and low-fluidity high performance concrete for forming a deck plate portion of the bridge by using a concrete casting apparatus. Accordingly, the construction cost can be reduced and the construction period can be shortened. In addition, because a cold joint does not occur, durability can be improved, and thus the life of the bridge can be increased.