Accelerated Drying Concrete via Water-Soluble Salts
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Solution Overview
Problem
Conventional concrete compositions face challenges with prolonged water vapor emissions, leading to delayed application of coatings and adhesives, increased construction time, and potential for moisture-related issues like mold growth and delamination, especially with lightweight aggregates that absorb water, prolonging drying times.
Innovation Solution
A cementitious composition incorporating hydraulic cement, superplasticizer, and water-soluble salts like alkali metal halides or nitrates, which reduce water vapor emissions by enhancing water retention in the concrete and inhibiting diffusion through the concrete surface, allowing faster attainment of desired internal humidity and surface dryness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional concrete compositions are used, then the concrete provides structural integrity and durability, but water vapor emissions persist for extended periods causing construction delays
Solution Approach 1:
The patent changes the chemical parameters of the concrete composition by incorporating water-soluble salts (such as calcium chloride, sodium nitrate, potassium sulfate) at controlled concentrations (0.5-5% by weight). These parameter changes modify the evaporation kinetics of water from the concrete, enabling faster moisture removal while maintaining concrete durability through proper formulation and curing protocols
Solution Approach 2:
The patent creates a composite concrete material by combining conventional cementitious materials with water-soluble salts. This composite approach allows the concrete to exhibit both structural integrity from the cement matrix and accelerated drying properties from the salt components, resolving the contradiction between durability and drying speed
2Weight of moving object
If lightweight aggregates are used to reduce concrete density, then the concrete becomes easier to handle and install, but water absorption increases prolonging drying times
Solution Approach 1:
The patent modifies the moisture-evaporation parameters by adding water-soluble salts that alter the vapor pressure and evaporation rate of water within the concrete matrix. This parameter change enables lightweight concrete to shed moisture faster despite its high water absorption capacity, turning a disadvantage into an advantage through controlled chemical composition
3Ease of operation
If high water content is used to improve workability and flow characteristics, then the concrete is easier to place and consolidate, but water vapor emissions increase extending the drying period
Solution Approach 1:
The patent changes the evaporation parameter by incorporating water-soluble salts that accelerate moisture removal from the concrete. This allows the concrete to maintain high water content for improved workability during placement, then rapidly reduce water vapor emissions afterward, effectively decoupling the workability phase from the drying phase
Solution Approach 2:
The patent applies preliminary action by incorporating water-soluble salts into the concrete mixture before placement. These salts are pre-positioned to accelerate evaporation once the concrete is placed and begins to set, allowing the concrete to achieve both high workability during mixing and rapid drying afterward without compromise
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 proposed solution significantly reduces water vapor emissions, enabling quicker application of coatings and adhesives, reducing construction delays, and enhancing the durability of concrete by promoting faster surface drying and reduced moisture-related issues.
Implementation Method 1
a substantial portion remains unreacted and is typically removed from concrete by evaporation
Implementation Method 2
inhibiting diffusion through the concrete surface
Data Source
AI summary
Cementitious compositions and processes for preparing and using the cementitious compositions are provided. The cementitious compositions are characterized by the property of a reduced or an attenuated water vapor emission from a cementitious mix and a concrete formed therefrom. Certain cementitious compositions are characterized by the property of accelerated drying while still maintaining good workability. Methods of improving water retention and surface drying of concrete, including lightweight concrete are provided. A water soluble ionic salt may be used to sequester water within the pores and capillaries of the cement paste and/or porous lightweight aggregate. In some examples, the salt may be added directly to concrete or aggregates may be infused with a water-salt solution to provide treated porous aggregates having improved water saturation and water retention.