Blast Furnace Slag Concrete with Expansive Additives
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Solution Overview
Problem
Conventional concrete compositions with low environmental impact struggle to achieve the same strength and fluidity as traditional concrete, often resulting in shrinkage and cracking due to high water content or limited applicability in architectural works.
Innovation Solution
A concrete composition incorporating blast furnace slag, an expansive additive, and a binder property inducing material, along with optimized water and aggregate content, to enhance strength, fluidity, and reduce shrinkage, while minimizing cement usage and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If low water content concrete composition is used to reduce environmental impact, then cement usage is reduced, but fluidity deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific expansive additives (calcium oxide, calcium hydroxide, calcium carbonate) and adjusting their content ratios (CaO: 0.1-5 mass%, Ca(OH)2: 0.1-5 mass%, CaCO3: 0.1-5 mass%). This allows the concrete to achieve both low water content (100-150 kg/m³) and good fluidity through chemical composition optimization rather than relying on high water content.
Solution Approach 2:
The patent creates a composite material system combining blast furnace slag (70-90 mass%), expansive additives, and minimal cement (10-30 mass%). This composite approach allows the blast furnace slag to provide the bulk structure while the expansive additives compensate for the lack of fluidity that would normally require high water content, thus reducing environmental impact while maintaining workability.
2Ease of operation
If high water content is used to improve fluidity, then fluidity is improved, but shrinkage and cracking increase
Solution Approach 1:
The patent optimizes the water content parameter to a specific range (100-150 kg/m³) and combines it with controlled amounts of expansive additives (CaO, Ca(OH)2, CaCO3). This parameter optimization ensures sufficient fluidity for construction while the expansive additives counteract shrinkage forces, preventing cracking and improving reliability.
Solution Approach 2:
The patent converts the potentially harmful effect of water (which causes shrinkage and cracking when evaporated) into a beneficial expansive force through the addition of expansive additives. These additives react with water to produce expansion that counteracts shrinkage, transforming the harmful shrinkage effect into a beneficial stress-relief mechanism that prevents cracking.
3Object-affected harmful factors
If cement content is reduced to lower environmental impact, then environmental impact is reduced, but strength may deteriorate
Solution Approach 1:
The patent creates a composite binder system where blast furnace slag (70-90 mass%) serves as the primary binding material, supplemented by expansive additives and minimal cement (10-30 mass%). The blast furnace slag provides the main structural strength while the expansive additives ensure proper setting and crack resistance, achieving both environmental sustainability and mechanical strength requirements.
Solution Approach 2:
The patent optimizes the chemical composition parameters including the CaO content (0.1-5 mass%), Ca(OH)2 content (0.1-5 mass%), and CaCO3 content (0.1-5 mass%) within the blast furnace slag. These parameter optimizations ensure that the reduced-cement mixture still achieves adequate compressive strength through the controlled chemical reactions and microstructure development of the slag-based system.
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 good fluidity and strength comparable to traditional concrete, while reducing shrinkage and environmental footprint, making it suitable for various architectural applications.
Implementation Method 1
contains expansive additive, and water... the concrete composition... reducing shrinkage
Data Source
AI summary
Provided is a concrete composition, including: blast furnace slag; at least any one of expansive additive and cement; and water, wherein a unit water content of the water is 130 kg/m3 or less; wherein a content of the cement is 22% by mass or less relative to the blast furnace slag, and wherein a slump flow value of the concrete composition is 40 cm or greater.