Variable Dose Superplasticizer for Cement Slump Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Excessive dosages of dispersants in concrete and mortar lead to increased initial workability but result in instability, causing segregation of aggregate constituents and extended setting times, making it challenging to achieve extended slump life without compromising stability.
Innovation Solution
A variable dose superplasticizer formulation comprising three components: an initial slump increasing agent, a moderating agent to control the initial slump, and a long-term slump retention agent, allowing for predictable slump retention and stability without excessive set retardation or strength reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the dosage of dispersing agent is increased to extend slump life, then the initial workability increases, but the mixture becomes unstable causing segregation of aggregate constituents
Solution Approach 1:
The dispersing agent is divided into two separate functional components: an initial slump agent that provides immediate workability enhancement, and a slump retention agent that maintains slump over time. This segmentation allows each component to perform its specific function without the harmful effects of excessive dosage, as the initial slump agent is used at lower doses and the slump retention agent acts later to extend slump life without causing segregation
Solution Approach 2:
The initial slump agent is applied during mixing to establish the desired initial workability. This preliminary action ensures that the concrete achieves the required slump immediately, allowing subsequent slump retention to be managed separately by the retention agent without compromising initial stability
2Duration of action of moving object
If the dosage of dispersing agent is increased to achieve longer slump life, then the slump retention is extended, but the setting time is excessively extended
Solution Approach 1:
The dispersing system is segmented into two distinct agents with different functional profiles: the initial slump agent provides immediate workability without significant set retardation, while the slump retention agent is specifically designed to extend slump life with minimal impact on setting time. This segmentation allows independent optimization of each function
Solution Approach 2:
The system transitions from static dispersant dosing to a dynamic two-stage approach where the initial slump agent acts immediately during mixing, and the slump retention agent provides time-dependent slump maintenance. This dynamic approach allows slump extension without proportionally extending setting time, as each agent operates in its optimal time window
3Duration of action of moving object
If the dosage of dispersing agent is increased to extend slump life, then the workability is maintained longer, but the initial workability becomes excessive causing instability
Solution Approach 1:
The dispersing function is segmented into two specialized agents: the initial slump agent that provides controlled immediate workability enhancement, and the slump retention agent that maintains slump over time. This segmentation prevents the need to use excessive doses of a single agent, allowing precise control of initial workability while achieving extended slump life through the retention agent's later action
Solution Approach 2:
The system changes the temporal parameters of dispersant action by using an initial slump agent for immediate effect and a slump retention agent for sustained effect. This parameter change allows the initial workability to be controlled at appropriate levels while achieving extended slump life through time-dependent retention mechanisms
Data Source
AI summary
The present invention relates to dispersants such as superplasticizers for hydratable cementitious compositions, and more particularly to methods for achieving variable degrees of longer slump life in concrete and mortar without loss of stability. This is achieved by using two admixture systems. The first admixture composition has multi-components for achieving initial-slump-enhancement, later-slump-retention, and limiting initial slump. The second admixture composition has the later-slump-enhancing component. Alternatively, conventional water reducers or superplasticizers can be employed initially, followed by the later-slump-enhancing admixture composition.