Semi-ordered Calcium Silicate Hydrate Cement Accelerator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing calcium silicate hydrate-based accelerators for cement hydration have unsatisfactory accelerating effects and are associated with high viscosity and corrosivity, limiting their economic and practical use in enhancing early strength of hydraulic and latent hydraulic binders.
Innovation Solution
A composition comprising a semi-ordered calcium silicate hydrate with an apparent crystallite size of 15 nm or less and less than 35% crystalline phases other than calcium silicate hydrate, combined with a polymeric water-soluble dispersant, which improves handling and accelerating properties without excessive viscosity or corrosivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If calcium silicate hydrate nuclei are added to accelerate cement hydration, then strength development is improved, but viscosity becomes excessively high making pumping and spraying difficult
Solution Approach 1:
The patent changes the particle size parameter of calcium silicate hydrate to nanoscale (15 nm or less) and controls crystallite size to achieve optimal accelerating effect while maintaining acceptable viscosity. This parameter optimization allows the composition to be pumped and sprayed easily while still providing strong acceleration of cement hydration.
Solution Approach 2:
The patent creates a composite composition combining calcium silicate hydrate with specific crystalline phases (xonotlite, tobermorite, and/or hillebrandite) in controlled proportions. This composite structure provides both the accelerating effect and manageable viscosity by balancing the properties of different crystalline phases.
2Productivity
If water-soluble calcium and silicon components are reacted to form calcium silicate hydrate, then accelerating effect is improved, but foreign ions such as chloride and nitrate are introduced causing corrosivity
Solution Approach 1:
The patent extracts and eliminates foreign ions (chloride, nitrate) from the composition by using calcium hydroxide and silicon dioxide as starting materials, which do not introduce harmful ions. The calcium silicate hydrate is formed through a clean reaction pathway that avoids contamination with corrosive foreign ions while maintaining the accelerating effect.
Solution Approach 2:
The patent uses readily available, inexpensive starting materials (calcium hydroxide, silicon dioxide, water) that do not introduce harmful ions. These simple, clean starting materials produce calcium silicate hydrate without the corrosivity associated with using water-soluble calcium and silicon components that contain foreign ions.
3Productivity
If crystalline calcium silicate hydrate is used as accelerator, then accelerating effect is improved, but viscosity and corrosivity increase
Solution Approach 1:
The patent optimizes the crystallite size parameter to 15 nm or less and controls the proportion of crystalline phases to achieve the best balance between accelerating effect and viscosity. This fine-tuning of physical parameters ensures the composition remains pumpable and sprayable while maintaining strong acceleration capability.
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 composition exhibits a pronounced accelerating effect on cement hydration, allowing easy handling and improved early strength development of hydraulic and latent hydraulic binders, particularly portland cement, while avoiding the limitations of high viscosity and corrosivity.
Implementation Method 1
Accelerating cement hydration by addition of calcium silicate hydrate nuclei to cement is known from WO 2010/026155. The strength development of a cement can thus be accelerated by the addition of such calcium silicate hydrate nuclei.
Implementation Method 2
a composition comprising a semi-ordered calcium silicate hydrate with an apparent crystallite size of 15 nm or less and less than 35% crystalline phases other than calcium silicate hydrate, combined with a polymeric water-soluble dispersant
Data Source
AI summary
A curing accelerator composition for building chemical mixtures comprises a mineral constituent and a polymeric water-soluble dispersant. The mineral constituent comprises a semi-ordered calcium silicate hydrate having an apparent crystallite size of 15 nm or less and less than 35% by weight of crystalline phases other than the semi-ordered calcium silicate hydrate. The composition displays a more pronounced accelerating effect than comparative compositions in which the mineral component comprises a calcium silicate hydrate having a higher degree of crystallinity.