White Cementitious Compositions with GGBFS for Efflorescence Control
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Solution Overview
Problem
White Portland cement-based compositions are prone to efflorescence and high alkali content, which can lead to long-term degradation in structural integrity and aesthetics, especially when used as a sole binder in cementitious applications.
Innovation Solution
The development of cementitious compositions comprising white Portland cement and light-colored ground granulated blast furnace slag (GGBFS), where the components are ground separately to control particle size distribution, reducing the need for high amounts of white cement and incorporating supplementary cementitious materials like limestone or pozzolans to enhance strength and reduce efflorescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If white Portland cement is used as a sole binder to achieve high compressive strength, then strength is improved, but efflorescence and alkali content increase leading to long-term degradation
Solution Approach 1:
The patent applies composite materials by combining white Portland cement with light-colored GGBFS and supplementary cementitious materials to create a blended cementitious composition. This composite approach reduces the harmful effects of pure white cement (efflorescence and high alkali content) while maintaining or improving compressive strength through the synergistic interaction of different binder components.
Solution Approach 2:
The patent changes the chemical and mineralogical parameters of the binder system by incorporating GGBFS and SCMs, which alter the composition to reduce alkali content and suppress efflorescence formation. The particle size distribution parameters are also optimized through separate grinding processes to enhance performance.
2Object-generated harmful factors
If white Portland cement content is reduced to decrease efflorescence, then efflorescence is reduced, but compressive strength may decrease
Solution Approach 1:
By creating a composite binder system with GGBFS and SCMs, the patent compensates for the reduced white cement content. The composite composition maintains compressive strength through the combined contributions of different materials, allowing white cement reduction without strength sacrifice.
Solution Approach 2:
The patent applies local quality by assigning different functional roles to different components: white Portland cement provides early strength and binding, while GGBFS and SCMs contribute to long-term strength development and efflorescence reduction. Each material is optimized for its specific function within the composite system.
3Ease of manufacture
If white Portland cement and GGBFS are interground together to simplify manufacturing, then manufacturing complexity is reduced, but particle size distribution control is compromised
Solution Approach 1:
The patent applies segmentation by dividing the grinding process into separate operations for white Portland cement and GGBFS. This allows independent optimization of particle size distribution for each material, achieving precise PSD control that would be difficult to obtain through intergrinding, while still simplifying overall manufacturing compared to multiple separate blending steps.
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 use of GGBFS in combination with white Portland cement reduces efflorescence and maintains or increases the compressive strength of cementitious compositions, even with reduced white cement content, while providing improved durability and aesthetic consistency.
Implementation Method 1
The white Portland cement and the light color GGBFS are advantageously ground separately, and without intergrinding with each other, in order to control their respective particle size distribution (PSD)
Implementation Method 2
A hardened cementitious composition comprises reaction products of a fresh cementitious mixture comprising water, white Portland cement, and light color GGBFS
Data Source
AI summary
A cementitious composition includes (i) white Portland cement having a Blaine fineness between about 350 m2/kg and about 550 m2/kg, a D90 between about 11 μm and about 50 μm, and a total combined iron oxide, manganese oxide, and chromium oxide content of less than 1.0% by weight and (ii) a light color ground granulated blast furnace slag (GGBFS) having a Blaine fineness greater than the Blaine fineness of the white Portland cement, a D90 less than the D90 of the white Portland cement, and a total combined iron oxide, manganese oxide, and chromium oxide content of less than 2.0% by weight. The cementitious composition may optionally include at least one of additional SCM, aggregate, fibers, or admixture. The cementitious composition can be a dry blend, a fresh cementitious mixture, or hardened cementitious composition. The cementitious composition can be precast concrete, stucco, GFRC, UHPC or SCC.