Fire Protection Mortar Thermal Stability via Calcium Silicate Cement
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Solution Overview
Problem
Current fire protection materials for tunnels face challenges such as high cost, energy consumption, thermal shrinkage, and limited availability of vermiculite, which affect their ability to withstand severe fire conditions like the Rf RWS test, and require improvements in thermal insulation and stability.
Innovation Solution
A fire protection mortar composition comprising 45-70% hydraulic setting calcium silicate cement, 8-20% calcite, 8-20% mica, 0-5% xonotlite, 0.1-10% expanded perlite, 0.1-10% fibers, and 0.01-4% air entrainer and foaming agents, which forms refractory crystalline phases at high temperatures, reducing heat transfer and providing effective thermal insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high aluminate cement is used as binder (e.g., Promat fire protection board), then thermal stability in Rf RWS condition is improved, but cost and energy consumption of raw materials increase
Solution Approach 1:
The patent changes the chemical composition parameters by using calcium silicate cement instead of high aluminate cement, and by adjusting the proportions of fillers and additives to achieve the required thermal stability at lower cost and energy consumption
Solution Approach 2:
The patent creates a composite material system combining calcium silicate cement with specific fillers (expanded perlite, vermiculite, calcite, mica) and additives to achieve the desired thermal performance without relying on expensive high aluminate cement alone
2Reliability
If high aluminate cement is used as binder (e.g., Promat fire protection board), then thermal stability in Rf RWS condition is improved, but cost of raw materials increases
Solution Approach 1:
The patent changes the chemical composition parameters by using calcium silicate cement instead of high aluminate cement, and by adjusting the proportions of fillers and additives to achieve the required thermal stability at lower cost and energy consumption
Solution Approach 2:
The patent creates a composite material system combining calcium silicate cement with specific fillers (expanded perlite, vermiculite, calcite, mica) and additives to achieve the desired thermal performance without relying on expensive high aluminate cement alone
3Temperature
If vermiculite is used as filler (e.g., CN 101863640 A), then thermal insulation is improved, but availability of vermiculite is limited
Solution Approach 1:
The patent uses different types of fillers in specific proportions adapted to local availability and requirements, allowing the formulation to be adjusted according to regional resource availability while maintaining thermal insulation performance
Solution Approach 2:
The patent creates a composite material system combining calcium silicate cement with specific fillers (expanded perlite, vermiculite, calcite, mica) and additives to achieve the desired thermal performance without relying on expensive high aluminate cement alone
4Strength
If cement content is increased to improve structural strength, then mechanical properties are improved, but thermal insulation performance deteriorates
Solution Approach 1:
The patent optimizes the cement content parameter within a specific range (45-70% by weight) and adjusts the proportions of fillers and additives to achieve the optimal balance between mechanical strength and thermal insulation performance
Solution Approach 2:
The patent creates a composite material system combining calcium silicate cement with specific fillers (expanded perlite, vermiculite, calcite, mica) and additives to achieve the desired thermal performance without relying on expensive high aluminate cement alone
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 mortar achieves superior thermal stability and reduced thermal shrinkage, enabling it to pass stringent fire tests like Rf RWS with a thinner application, while being cost-effective and environmentally friendly, with a cured density below 1200 kg/m³ and excellent freeze-thaw resistance.
Implementation Method 1
the mortar achieves superior thermal stability and reduced thermal shrinkage, enabling it to pass stringent fire tests like Rf RWS with a thinner application
Implementation Method 2
forms refractory crystalline phases at high temperatures
Data Source
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AI summary
A composition for the preparation of a fire protection mortar comprising - 45 to 70% by weight of cement binder, - 8 to 20% by weight calcite, - 8 to 20% by weight mica, - 0 to 5% by weight of xonotlite, - 0.1 to 20% by weight of expanded perlite, - 0.1 to 10% by weight of fibers, - 0.01 to 2% by weight of air entrainer and foaming agent, - 0.01 to 2% by weight of processing aids.