Lightweight Insulating Mortar Composition Air Stability
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Solution Overview
Problem
Current insulating mortars struggle to achieve low densities while maintaining workability and mechanical strength, as the addition of lightening fillers often leads to issues with granular particle concentration, pumpability, and air stability, making it difficult to achieve densities below 250 kg/m³ with conventional air-entraining additives.
Innovation Solution
A composition combining mineral hydraulic binders with lightening mineral fillers and a surfactant-type air-entraining agent, along with a thickening agent, to significantly reduce density while maintaining stability and workability, comprising at least 40% by weight of lightening mineral fillers and an air-entraining agent, without the need for additional stabilizers, and using a specific binder mix to control pH and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional air-entraining additives are used to reduce mortar density, then low density is achieved, but air stability deteriorates and bubbles collapse quickly
Solution Approach 1:
The patent uses a composite approach by combining multiple air-entraining agents with different mechanisms (surface-active substances and foaming agents) to create a synergistic effect. This composite additive system stabilizes air bubbles through multiple simultaneous actions: surface tension reduction, foam formation, and bubble wall reinforcement, preventing the rapid collapse seen with conventional single-agent systems.
Solution Approach 2:
The patent modifies the chemical composition parameters of the air-entraining system by selecting specific surface-active substances (anionic, cationic, or nonionic) and foaming agents with controlled molecular structures. These parameter changes optimize the interfacial properties of bubble walls, enhancing their stability during pumping and application while maintaining low density.
2Quantity of substance
If lightening fillers are increased to achieve lower density, then density reduction is improved, but workability and pumpability deteriorate
Solution Approach 1:
The patent optimizes the particle size distribution parameter of lightening fillers, using a mix of different粒径 (particle sizes) to improve packing efficiency and reduce maximum granular stacking. This parameter optimization maintains lower density while improving paste flowability and pumpability compared to using单一粒径 (single particle size) fillers.
Solution Approach 2:
The patent introduces chemical additives as intermediaries between the lightening fillers and the cementitious matrix. These additives modify the interfacial properties between filler particles and the binding phase, reducing agglomeration and improving dispersion, thereby maintaining workability despite high filler content.
3Quantity of substance
If foam is introduced to achieve very low density, then density is reduced, but preparation complexity and time increase
Solution Approach 1:
The patent employs self-service air entrainment where the chemical additives automatically generate and stabilize air bubbles during the normal mixing process without requiring external foam generation equipment. The surface-active substances and foaming agents spontaneously form stable bubbles when mixed with water, eliminating the need for complex foam generators or specialized preparation procedures.
Solution Approach 2:
The patent replaces mechanical foam generation systems with a chemical approach. Instead of using mechanical agitation or foam generators to introduce and stabilize air, the patent uses chemical surfactants and foaming agents that autonomously create and stabilize bubbles through surface tension reduction and foam film formation, simplifying the overall system.
4Quantity of substance
If polystyrene beads are used to achieve low density, then density is reduced, but fire resistance deteriorates
Solution Approach 1:
The patent changes the material composition parameter by selecting mineral-based lightening fillers (expanded perlite, vermiculite, expanded clay, pumice) instead of organic polystyrene beads. These mineral fillers inherently possess fire resistance while maintaining low density, eliminating the fire safety issue associated with organic fillers.
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 solution achieves a thermal conductivity of less than 55 mW/m.K and a compressive strength of at least 0.40 MPa, allowing for stable, lightweight, and thermally insulating mortars that can be used in construction applications, with improved acoustic properties and retention of lightening properties during pumping and spraying.
Implementation Method 1
an air-entraining agent of surfactant type chosen from organic fatty acids, sulphated compounds, sulphonated compounds and/or natural wood resins
Implementation Method 2
The use of these types of air entrainers remains limited, however, because it is difficult to obtain the stability of the entrained air
Implementation Method 3
a thickening agent chosen from polyvinyl alcohols, starch ethers, cellulose ethers, guar ethers or clays such as bentonite
Implementation Method 4
The present invention relates to a lightweight thermally insulating mortar composition, whose low density of the paste after mixing remains stable
Data Source
AI summary
The present invention relates to a thermally insulating mortar composition devoid of siliceous, calcareous and/or siliceous/calcareous aggregates with a particle size of greater than 100 µm and comprising a mixture of at least: - 40% of inorganic lightening fillers, the bulk density of which is less than 200 kg/m3, - an inorganic binder chosen from sulfoaluminate cements, high-alumina cements and/or binary or ternary binders comprising at least one high-alumina or sulfoaluminate cement, - an air-entraining agent of surfactant type chosen from organic fatty acids, sulfate compounds, sulfonate compounds and/or natural wood resins, and - a viscosifying agent chosen from polyvinyl alcohols, starch ethers, cellulose ethers, guar ethers or clays, such as bentonite. This composition can be used in a spraying device operating in continuous or noncontinuous mode and makes it possible to obtain lightweight hardened mortars by virtue of a very good stability of the paste. The present invention also relates to a process for the preparation of a construction material, to the material thus obtained and to the use thereof in the construction field.