Lightweight Gypsum-Cement Panels with Coated Perlite
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Solution Overview
Problem
Current gypsum-cement based structural cement panels fail to meet the required shear rating in certain locations and have limitations in water durability and thermal resistance compared to wood-based panels, and they are heavier than desired.
Innovation Solution
The development of lightweight gypsum-cement compositions reinforced with glass fibers and coated expanded perlite particles, which replace hollow ceramic or polymer microspheres, enhancing mechanical performance, water durability, and thermal stability while maintaining reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gypsum-cement based structural cement panels are used, then fire resistance and non-combustibility are improved, but water durability and thermal resistance deteriorate compared to wood-based panels
Solution Approach 1:
The patent employs a composite material system combining gypsum-cement binder with hydrophobic expanded perlite particles and glass fiber reinforcement. This composite structure integrates the fire resistance of gypsum-cement with the water repellency of hydrophobic perlite and the mechanical strength of glass fibers, achieving both fire resistance and improved water durability simultaneously
Solution Approach 2:
Hydrophobic expanded perlite particles serve as intermediary agents between the gypsum-cement matrix and water. The hydrophobic coating on perlite particles creates a water-repellent interface that prevents water penetration while maintaining the inherent fire resistance of the gypsum-cement base material
2Strength
If traditional structural cement panels are used, then structural strength is achieved, but weight increases reducing efficiency
Solution Approach 1:
The patent changes the density parameter of the panel by incorporating lightweight expanded perlite particles (density 0.1-0.3 g/cm³) as aggregate, reducing overall panel weight while maintaining structural integrity through optimized glass fiber reinforcement content (0.5-2.0% by weight)
Solution Approach 2:
The patent applies local quality enhancement by concentrating glass fiber reinforcement in critical load-bearing regions and using hydrophobic perlite particles primarily in the matrix structure, achieving optimal strength-to-weight ratio with localized material property optimization
3Weight of stationary object
If hydrophilic perlite particles are used, then lightweight structure is achieved, but water absorption increases causing swelling
Solution Approach 1:
The patent fundamentally changes the surface property parameter of perlite particles by applying hydrophobic coatings (silane, silicone, or wax), transforming them from water-attracting to water-repelling surfaces while maintaining their lightweight structural function
Solution Approach 2:
The hydrophobic coating on perlite particles provides a durable but replaceable protective layer that prevents water absorption; even if the coating degrades over time, the base perlite structure remains intact and can be re-coated, providing long-term water protection at low cost
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 provides panels with improved shear strength, water resistance, and thermal stability at a lower weight, meeting the performance requirements for structural cement panels and allowing for more efficient use of building volume and better resistance to moisture-induced swelling.
Implementation Method 1
coated expanded perlite particles, which replace hollow ceramic or polymer microspheres, enhancing mechanical performance, water durability, and thermal stability
Implementation Method 2
gypsum-cement compositions reinforced with glass fibers
Implementation Method 3
enhancing mechanical performance, water durability, and thermal stability
Data Source
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AI summary
Structural cement panel for resisting transverse and shear loads equal to transverse and shear loads provided by plywood and oriented strain board, when fastened to framing for use in shear walls, flooring and roofing systems. The panels provide reduced thermal transmission compared to other structural cement panels. The panels employ one or more layers of a continuous phase resulting from curing an aqueous mixture of calcium sulfate alpha hemihydrate, hydraulic cement, coated expanded perlite particles filler, optional additional fillers, active pozzolan and lime. The coated perlite has a particle size of 1-500 microns, a median diameter of 20-150 microns, and an effective particle density (specific gravity) of less than 0.50 g/cc. The panels are reinforced with fibers, for example alkali-resistant glass fibers. The preferred panel contains no intentionally added entrained air. A method of improving fire resistance in a building is also disclosed.