Fibre-Reinforced Building Board Dimensional Stability
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Solution Overview
Problem
The dimensional stability of fibre-reinforced building boards manufactured using hydraulic-setting compositions is insufficient, despite the use of mica and wollastonite, which affects their strength and processability.
Innovation Solution
A hydraulic-setting composition comprising a cementitious binder, silica, cellulose fibres, mica, wollastonite, and an aluminium compound that releases Al3+ ions during autoclave curing, with specific ratios of these components to enhance dimensional stability and strength, is used to produce fibre-reinforced building boards via the Hatschek process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If mica and wollastonite are added to hydraulic-setting composition to improve dimensional stability, then the dimensional stability is partially improved, but the dimensional stability remains insufficient
Solution Approach 1:
The patent uses a composite material approach by combining mica, wollastonite, and aluminium compounds in specific proportions within the hydraulic-setting composition. This multi-component composite system synergistically improves dimensional stability more effectively than individual additives alone, resolving the insufficiency of dimensional stability while maintaining cost-effectiveness.
Solution Approach 2:
The patent optimizes the quantitative parameters of the composition by specifying precise weight percentages: mica (8-12%), wollastonite (4-8%), and aluminium compound (2-6%). By carefully controlling these parameter values, the patent achieves sufficient dimensional stability that was not obtainable with conventional additive levels.
2Stability of the object's composition
If aluminium compound is added to enhance dimensional stability, then wet-dry dimensional stability is significantly improved, but the composition complexity increases
Solution Approach 1:
The patent manages composition complexity by defining specific parameter ranges for the aluminium compound (2-6 wt%) and specifying its solubility characteristics in the alkaline cementitious matrix. This parameter-based approach ensures improved wet-dry dimensional stability while keeping the composition formulation manageable and not excessively complex.
3Reliability
If aluminium hydroxide is used as the aluminium compound, then solubility in alkaline matrix is maximized, but the cost increases
Solution Approach 1:
The patent addresses the cost-solubility trade-off by specifying aluminium hydroxide as the preferred aluminium compound with a D50 particle size of 10-200 μm. This parameter specification ensures high solubility in the alkaline cementitious matrix during autoclave curing while maintaining cost-effectiveness through controlled particle size and optimized composition ratios.
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 significantly improves the wet-dry dimensional stability and delamination resistance of the building boards, making them suitable for applications such as interior backer boards and exterior façade backer boards, while maintaining cost-effectiveness and handling strength.
Implementation Method 1
an aluminium compound, selected from the group consisting of aluminium hydroxide, bauxite or boehmite, and their mixtures, capable to release Al3+
Implementation Method 2
obtained by the autoclave curing of a hydraulic-setting composition
Implementation Method 3
a hydraulic-setting composition for manufacturing an autoclave cured fibre-reinforced building board, comprising as components : (a) a cementitious binder
Data Source
AI summary
A hydraulic-setting composition for manufacturing an autoclave cured fibre-reinforced building board of improved dimensional stability, comprising as components: (a) a cementitious binder, (b) silica, (c) reinforcing cellulose fibres, said composition further comprising the additional components in % with respect to the total weight of the composition at dry state: (d) 8-12% of mica, (e) 4-8% of wollastonite, and (f) an amount of at least one aluminium compound capable to release AI3+ in autoclave curing conditions, said amount being such that the dry composition comprises 0,02-2,2% of Al3+, as well as (g) optionally other additives, the sum of amounts of components (a) to (g) being equal to 100 weight %, and board so obtained.