Durability Improving Agent for Cement Composition
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Solution Overview
Problem
Conventional cement compositions face challenges in maintaining freezing-thawing resistance and shrinkage reduction simultaneously, as additives like air entraining agents and shrinkage reducing agents often compromise one another's effectiveness, leading to inadequate durability, especially in cold regions.
Innovation Solution
A durability improving agent comprising a hydrocarbon-based compound with an average molecular weight of 150 to 600 and a pour point of 20° C. or less, combined with a compound of the general formula R—O-(AO)n—H, is added to the cement composition, enhancing freezing-thawing resistance, shrinkage reduction, and substance blocking properties without compromising original durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an air entraining component is added to a cement composition, then air bubbles are entrained to improve freezing-thawing resistance, but the air bubbles cannot be sufficiently entrained after hardening and the freezing-thawing resistance is insufficient
Solution Approach 1:
The air entraining component is added to the cement composition before hardening occurs, allowing air bubbles to be entrained during the plastic state when the cement matrix is still flexible. This preliminary action enables sufficient air bubble incorporation before the matrix sets, resolving the contradiction between improving freezing-thawing resistance and achieving adequate air entrainment efficiency.
2Stability of the object's composition
If a shrinkage reducing agent is added to a cement composition, then drying shrinkage is reduced, but the freezing-thawing resistance is dramatically harmed
Solution Approach 1:
The invention introduces an intermediary substance (the specific air entraining component with surfactant properties) that mediates between the shrinkage reducing agent and the cement matrix. This intermediary allows the shrinkage reducing agent to function while simultaneously improving air bubble stability and freezing-thawing resistance, thus resolving the contradiction between shrinkage reduction and freezing-thawing resistance.
3Reliability
If the strength of the cement composition is increased to ensure freezing-thawing resistance, then durability is improved, but the complexity of achieving this strength increase is not reduced
Solution Approach 1:
The air entraining component performs multiple functions simultaneously: it entrains air bubbles for freezing-thawing resistance, acts as a surfactant to stabilize the mixture, and reduces the need for complex curing processes. The component serves itself by incorporating multiple protective functions into a single additive, simplifying the overall system while improving durability.
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 effectively improves freezing-thawing resistance and shrinkage reduction while maintaining or enhancing durability, reducing cracking, and ensuring good air entrainment, thus addressing the limitations of conventional additives.
Implementation Method 1
a frost damage resistant cement admixture material characterized by containing an AE agent having a high-range water reducing agent
Implementation Method 2
improves freezing-thawing resistance and shrinkage reduction while maintaining or enhancing durability, reducing cracking, and ensuring good air entrainment
Data Source
AI summary
It is an object of the present invention to provide a durability improving agent for a cement composition that improves the freezing-thawing resistance of the cement composition and also exhibits a sufficient shrinkage reducing performance as well, and a cement composition including such a durability improving agent. Specifically, the present invention provides a durability improving agent for a cement composition, characterized by comprising a hydrocarbon-based compound having an average molecular weight of 150 to 600 and a pour point of 20° C. or less as an active ingredient, and a cement composition including such durability improving agent.