Graded Aggregate Composition for Fresh Flow and Shrinkage Control
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Solution Overview
Problem
Existing compositions containing aggregate, binder, and water, such as concrete and mortar, face challenges in achieving both high flowability in the fresh state and limited autogenous shrinkage.
Innovation Solution
The composition includes specific ratios of small-, medium-, and large-diameter aggregates with controlled BET specific surface areas, porosities, and pore radii, along with a defined water-to-aggregate ratio, to enhance flowability and limit autogenous shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the water-to-aggregate ratio is increased to improve flowability, then the composition becomes more workable, but the strength and durability deteriorate
Solution Approach 1:
The patent utilizes porous aggregate materials with specific pore structures to improve flowability while maintaining strength. The porous structure allows for better water distribution and reduces the need for excessive water to achieve desired workability, thereby resolving the contradiction between flowability and strength.
Solution Approach 2:
The patent employs composite aggregate systems combining different particle sizes, shapes, and porosity levels. This composite approach optimizes the packing efficiency and water distribution, enabling good flowability with reduced water content, thus maintaining both workability and strength.
2Strength
If the water-to-aggregate ratio is decreased to improve strength, then the strength increases, but the flowability deteriorates
Solution Approach 1:
The porous aggregate structure acts as an internal water reservoir, releasing water gradually during mixing and placement. This allows for lower overall water content while maintaining adequate flowability, thus resolving the contradiction between strength and workability.
Solution Approach 2:
The patent changes the physical parameters of the aggregate, specifically its porosity and pore size distribution, to optimize the water-cement-aggregate interaction. This enables achieving both high strength and good flowability by controlling the aggregate's internal structure rather than simply adjusting water content.
3Strength
If fine aggregate with high specific surface area is used to improve strength, then the strength increases, but the water demand increases causing shrinkage
Solution Approach 1:
The porous aggregate provides internal porosity that compensates for the high surface area of fine particles. The pores store water that would otherwise be consumed by surface adhesion, reducing the overall water demand while maintaining strength through the porous structure's contribution to the composite material properties.
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 achieves a higher degree of flowability in the fresh state while significantly reducing autogenous shrinkage, as demonstrated by improved flow values and limited shrinkage strains in mortar and concrete samples.
Implementation Method 1
the medium-diameter aggregate and the large-diameter aggregate each have porosity of 10% or more
Implementation Method 2
in a range of pore radii from 0.01 to 1 μm, the small-diameter aggregate, the medium-diameter aggregate, and the large-diameter aggregate each have a pore radius having a largest differential pore volume in a range from 0.03 to 0.3 μm
Implementation Method 3
A composition containing aggregate, binder, and water, such as concrete and mortar
Data Source
AI summary
The present invention aims at providing a composition containing aggregate, binder, and water that can achieve a higher degree of both flowability in the fresh state and a limitation of autogenous shrinkage. A composition of the present invention contains binder, aggregate, and water, wherein the aggregate contains: small-diameter aggregate classified into particle diameters of 300 μm or more and less than 1.18 mm; medium-diameter aggregate classified into particle diameters of 1.18 mm or more and less than 4.75 mm; and large-diameter aggregate classified into particle diameters of 4.75 mm or more and 5 mm or less; wherein a ratio of volume of water to a sum of volume of the binder and volume of aggregate having particle diameters of 5 mm or less is 15% or more and 26% or less, and the small-diameter aggregate, the medium-diameter aggregate, and the large-diameter aggregate each have a BET specific surface area of 0.4 (m2/g) or less.