Lightened Finishing Screed Composition for Strength and Insulation
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Solution Overview
Problem
Traditional screeds in the building industry are heavy, thermally conductive, environmentally impactful, and lack thermal and sound insulation, requiring oversized structures and increased costs, while existing lightened screeds still rely on non-renewable materials and have high ecological footprints.
Innovation Solution
A composition using hydraulic lime as a binder, combined with cork, expanded clay, expanded perlite, diatomite powder, and cellulose fibers, optimized for particle size and proportions to achieve a lightweight, thermally insulated, and soundproof screed with improved mechanical strength and breathability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional sand and cement screed is used, then mechanical strength is achieved (≥5 Newtons/mm²), but weight and thermal conductivity increase significantly
Solution Approach 1:
The patent uses a composite material system combining cement binder with lightweight aggregate particles (expanded perlite, expanded clay, pumice) to create a screed that achieves mechanical strength ≥5 Newtons/mm² while reducing specific gravity to 800-1500 kg/m³. The composite structure allows the cement matrix to provide strength while the lightweight aggregates reduce overall density.
Solution Approach 2:
The patent incorporates porous lightweight aggregates (expanded perlite, expanded clay, pumice) with high void content into the screed composition. These porous materials have densities of 800-1500 kg/m³ compared to traditional sand at 1600-1800 kg/m³, enabling the screed to achieve the required mechanical strength while reducing specific gravity by 30-50%.
2Strength
If traditional sand and cement screed is used, then mechanical strength is achieved, but thermal insulation performance deteriorates
Solution Approach 1:
The patent creates a composite screed combining cement binder with thermal insulating aggregates (expanded perlite, expanded clay, pumice) to achieve mechanical strength ≥5 Newtons/mm² while reducing thermal conductivity to 0.2-0.4 W/(m·K). The composite structure provides both structural integrity and thermal insulation properties.
Solution Approach 2:
The patent uses porous lightweight aggregates with high void content that trap air pockets, significantly reducing thermal conductivity. The porous structure of expanded perlite, expanded clay, and pumice creates thermal barriers within the screed matrix, achieving thermal conductivity of 0.2-0.4 W/(m·K) while maintaining mechanical strength.
3Weight of moving object
If cement and clay lightened screed is used, then weight is reduced and thermal insulation is improved, but water vapor permeability deteriorates
Solution Approach 1:
The patent applies local quality by using hydraulic lime in specific proportions (10-30% by weight) within the binder composition to provide breathability in critical areas, while maintaining cement for overall strength. This localized application of breathable materials ensures water vapor permeability without compromising structural integrity.
Solution Approach 2:
The patent changes the chemical composition parameters of the binder by incorporating hydraulic lime (10-30% by weight) alongside cement. This parameter change increases water vapor diffusion resistance coefficient to μ < 5 while maintaining mechanical strength ≥5 Newtons/mm² and specific gravity 800-1500 kg/m³, achieving breathability in the lightened screed.
4Strength
If cement is used as binder, then mechanical strength is achieved, but ecological impact increases due to high production temperature
Solution Approach 1:
The patent changes the binder composition parameters by incorporating hydraulic lime (10-30% by weight) which requires lower production temperature (900-1100°C) compared to cement (1450°C). This parameter change reduces CO2 emissions and energy consumption while maintaining mechanical strength ≥5 Newtons/mm² through the synergistic combination of lime and cement.
Solution Approach 2:
The patent recovers and utilizes industrial by-products (fly ash, slag) as partial replacements for cement and lime in the binder composition. This discarding of waste materials and recovering their value reduces ecological impact and production costs while maintaining mechanical strength through the pozzolanic reactions of these by-products.
5Strength
If sand is used as inert material, then mechanical strength is achieved, but environmental impact increases due to quarry extraction
Solution Approach 1:
The patent recovers and utilizes industrial by-products (fly ash from power plants, slag from steel production) as inert materials replacing quarried sand. These discarded waste materials are recovered and transformed into valuable construction components, eliminating the need for sand extraction from quarries while maintaining mechanical strength ≥5 Newtons/mm².
Solution Approach 2:
The patent uses industrial by-products (fly ash, slag) that would otherwise be waste materials requiring disposal. These materials serve the dual purpose of waste elimination and providing functional inert material for the screed, achieving mechanical strength while eliminating environmental harm from quarry extraction.
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 a lightweight screed with reduced thermal conductivity, enhanced thermal and sound insulation, and lower environmental impact, while maintaining mechanical strength and breathability, using renewable materials.
Implementation Method 1
The binder comprises hydraulic lime. The percentage of hydraulic lime in the composition is comprised between 20% and 36%
Implementation Method 2
cork, expanded clay, expanded perlite... A type of lightened screed that comprises cement as binder, and perlite as inert material is also known. Such a type of lightened screed has a mechanical, thermal and weight performance that is substantially similar to that of the lightened screed comprising cement and clay.
Implementation Method 3
A type of lightened screed that comprises cement as binder, and perlite as inert material is also known. cement is not permeable to water, and consequently such a type of lightened screed has a water vapor diffusion resistance coefficient (μ) greater than 5, making the screed non-breathable.
Data Source
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AI summary
Composition for a lightened finishing screed comprising a binder and inert materials; wherein the binder comprises hydraulic lime; and the inert materials comprise: cork, expanded clay, expanded perlite, diatomaceous earth powder, and fiber material.