Cementitious Binders With Calcium Sulfoaluminate and Sulfates
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Solution Overview
Problem
Current cementitious compositions containing calcium sulfoaluminate and pozzolanic materials face challenges in achieving high mechanical strengths, particularly at early ages, and require prolonged wet curing and favorable temperatures due to slow pozzolanic reactions, which are environmentally costly and inefficient.
Innovation Solution
A cementitious composition comprising 72-94% ground granulated blast furnace slag, at least 0.5% calcium sulfoaluminate, 1.2-11% inorganic sulfate, and a total sulfate content of 3-12%, with a maximum 5% calcium sulfoaluminate and minimal Ordinary Portland Cement, forming a wet paste or concrete mixture that includes aggregates, optimizing mechanical and chemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If pozzolanic materials are used in cementitious compositions, then environmental friendliness and cost-effectiveness are improved, but mechanical strength development is slowed and curing time is extended
Solution Approach 1:
The patent applies preliminary action by incorporating calcium sulfoaluminate cement (CSA) and sulfates into the binder composition before mixing with pozzolanic materials. These components pre-establish the chemical environment necessary for rapid early-age strength development, allowing the pozzolanic materials to react more quickly than they would alone. The CSA and sulfates create ettringite and other hydration products in advance that accelerate the overall hardening process while maintaining the environmental benefits of using pozzolanic substitutes for Portland cement.
2Object-affected harmful factors
If ground granulated blast furnace slag is used as a binder, then environmental impact is reduced, but early-age mechanical strength is decreased
Solution Approach 1:
The patent employs composite materials by combining ground granulated blast furnace slag (GGBFS) with calcium sulfoaluminate cement (CSA) and sulfates to create a blended binder system. This composite approach leverages the environmental advantages of GGBFS while compensating for its slow reactivity through the addition of CSA, which provides rapid early-age strength. The synergistic interaction between these components produces a binder that achieves both sustainability goals and mechanical performance requirements.
Solution Approach 2:
The patent applies parameter changes by modifying the chemical composition of the binder system through the addition of specific sulfate compounds (calcium sulfate hemihydrate, anhydrous calcium sulfate, or calcium sulfate dihydrate) at controlled levels (1.2-11% by weight). This chemical parameter adjustment accelerates the hydration reactions of GGBFS, enabling faster strength development while maintaining the low-carbon benefits of slag-based binders. The sulfate addition transforms the slow-reacting slag into a more reactive system without compromising environmental performance.
3Reliability
If prolonged wet curing is applied to pozzolanic materials, then complete hydration is achieved, but time and energy consumption increase
Solution Approach 1:
The patent uses calcium sulfoaluminate cement (CSA) and sulfates as intermediary substances that mediate between the pozzolanic materials and water during hydration. These intermediaries facilitate faster and more complete reactions by creating a chemically active environment that promotes rapid pozzolanic activity. The CSA and sulfates act as catalysts that speed up the hydration process, allowing the pozzolanic materials to achieve complete hydration in a shorter time frame with reduced curing requirements compared to traditional Portland cement systems.
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 achieves high mechanical strengths over short and medium-term periods, reducing the need for prolonged curing and minimizing environmental impact while controlling costs, with improved compressive strength development and reduced carbon dioxide emissions.
Implementation Method 1
A pozzolan is a siliceous or alumino-siliceous material, which, in finely divided form and in the presence of moisture, chemically reacts with calcium hydroxide released by the hydration of Portland cement to form calcium silicate hydrate and other cementitious compounds.
Implementation Method 2
ground granulated blast furnace slag (GGBFS) is considered a latently hydraulic material or binder, exhibiting hydraulic reactivity in the presence of an alkaline activator such as ordinary Portland cement (OPC) and/or a sulfate activator calcium sulfate. In the presence of calcium sulfate, the main hydration products formed are the ettringite and C-S-H phases.
Implementation Method 3
the binder and water forming a wet cementitious paste
Data Source
Figure 1
AI summary
A cementitious composition including: a binder containing (a) 60-94%, by weight, of at least one pozzolanic material; (b) at least 0.5% calcium sulfoaluminate (CSA), by weight; (c) 1.2-1 1% by weight, expressed as SO3, of at least one inorganic sulfate selected from the group of sulfates consisting of a calcium sulfate hemihydrate, an anhydrous calcium sulfate, a calcium sulfate dihydrate, a sodium sulfate, and a sodium calcium sulfate; and (d) a total sulfate content of at least 3%, by weight, expressed as SO3, the cementitious composition including, at most, 3% natural lime, the cementitious composition including, at most, 10% alumina cement, the contents of the composition being calculated on a dry, aggregateless basis.