Hazing Control in Carbonatable Calcium Silicate Cements
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Solution Overview
Problem
Carbonatable calcium silicate-based cements and concretes suffer from hazing due to soluble salts like alkali sulfates and chlorides, which affect their aesthetic and durability, and existing methods do not effectively address this issue.
Innovation Solution
The method involves adding admixtures such as calcium aluminate, ground granulated blast furnace slag (GGBFS), and liquid calcium salts to the concrete mixture, along with controlled curing conditions like temperature ramping and high relative humidity, to form low solubility materials that prevent or reduce hazing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If carbonatable calcium silicate-based cements are used to reduce CO2 emissions and energy consumption, then environmental performance is improved, but hazing occurs due to soluble salts affecting aesthetic appearance
Solution Approach 1:
The patent converts the harmful effect of soluble salts (which cause hazing) into a beneficial process by inducing controlled efflorescence. The soluble salts are intentionally allowed to migrate to the surface and crystallize, forming a protective layer that prevents further salt migration and hazing, while simultaneously improving durability and aesthetic appearance through controlled surface formation
Solution Approach 2:
The patent changes the curing parameters (temperature, humidity, CO2 concentration) to control the efflorescence process. By optimizing these parameters, the soluble salts are directed to form desirable surface deposits rather than hazing, transforming the harmful salt presence into a controlled surface treatment that improves overall concrete performance
2Object-affected harmful factors
If admixtures are added to prevent hazing, then aesthetic appearance is improved, but concrete mixture complexity increases
Solution Approach 1:
The patent employs admixtures that enable the concrete system to self-regulate salt migration and surface formation. The admixtures create conditions where the concrete automatically controls efflorescence development without requiring external intervention or complex processing, allowing the system to self-organize the salt deposits into aesthetically pleasing patterns while maintaining simplicity in application
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 significantly mitigates or eliminates hazing in carbonatable calcium silicate-based cements and concretes, improving their appearance and durability while maintaining reduced energy consumption and a lower carbon footprint.
Implementation Method 1
adding to the concrete mixture an admixture comprising one or more components capable of reacting with one or more of soluble alkali, alkaline earth, sulfate or chloride ions to form a low solubility material
Implementation Method 2
the admixture comprises a liquid admixture which is an aqueous solution comprising one or more highly soluble calcium salts
Implementation Method 3
this new cement sequesters CO2 when cured into concrete products because CO2 is needed to react with the carbonatable calcium silicate materials during the curing process to form concrete products
Implementation Method 4
These deposits typically form as soluble calcium hydroxide migrates from the interior of the sample to the outer surface and subsequently reacts with atmospheric CO2 to form calcium carbonate
Implementation Method 5
curable concrete mixture is received, adding to the curable concrete mixture a haze suppressing admixture, and then curing the curable concrete mixture to form a concrete product
Data Source
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AI summary
The invention provides novel methods and compositions that mitigate the occurrence of hazing of products made from carbonatable calcium silicate-based cements. The methods and compositions of the invention may be applied in a variety of cement and concrete components in the infrastructure, construction, pavement and landscaping industries.