Millable Recyclable Paving Fabric Interlayer System
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Solution Overview
Problem
Current geosynthetic interlayers for roadway pavements, such as needle-punched nonwoven fabrics and fiberglass-based mats, face issues with milling and recycling, inadequate stress absorption, moisture barrier effectiveness, and durability, leading to increased maintenance costs and safety concerns for workers.
Innovation Solution
A millable and recyclable paving fabric interlayer system comprising a flexible, nonwoven fabric with a tack coat, which can be conjoined with a scrim or grid, providing high elongation, effective asphalt retention, and improved durability, allowing for seamless installation and recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If needle-punched nonwoven paving fabric is used as geosynthetic interlayer, then stress absorption and moisture barrier performance are improved, but milling operations are disrupted due to large fabric pieces wrapping and clogging milling drums
Solution Approach 1:
The nonwoven fabric is engineered to segment into small particles during milling operations, preventing large pieces from wrapping and clogging milling drums while maintaining the fabric's moisture barrier functionality
Solution Approach 2:
The physical and chemical parameters of the nonwoven fabric are optimized to balance durability for moisture barrier performance with controlled disintegration characteristics for easy milling and recycling
2Ease of operation
If fiberglass-based paving mats are used to enable milling and recycling, then ease of operation during milling is improved, but stress absorption capacity and moisture barrier effectiveness are insufficient
Solution Approach 1:
The invention uses a composite nonwoven fabric structure combining high-elongation fibers with controlled bonding characteristics, achieving both the stress absorption capacity of thick materials and the millability of thinner materials
Solution Approach 2:
The fabric's physical parameters including fiber length, fiber diameter, basis weight, and elongation are optimized to provide sufficient stress absorption capacity while maintaining millability and recyclability
3Ease of manufacture
If fiberglass-based paving mats are used, then milling and recycling are facilitated, but worker safety is compromised due to brittle nature and potential for tearing and splitting
Solution Approach 1:
The fabric's elongation and tensile strength parameters are enhanced through fiber selection and construction methods, making the material more ductile and resistant to sudden failure, thereby reducing worker exposure to sharp fragments
Solution Approach 2:
The nonwoven fabric is designed as a disposable interlayer that provides its function during pavement service life and then easily mills into safe, small particles for recycling, eliminating long-term safety concerns
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 system offers a robust moisture barrier with low permeability, enhanced stress absorption, and improved durability, reducing maintenance costs and worker safety risks, while maintaining continuous integrity over uneven surfaces and during construction stresses.
Implementation Method 1
the interlayer fabric described herein has a tight, needlepunched, nonwoven structure that absorbs and retains the asphalt tack coat to provide a durable, stable waterproofing membrane
Implementation Method 2
These fabrics are combined in the field with an asphalt cement to form a thick interlayer
Implementation Method 3
The bond between the liner and the two road layers is achieved by means of a bonding agent such as bitumen
Data Source
Figure 1
AI summary
A millable, recyclable, paving fabric interlayer system for the construction and repair of roadways and other load-bearing surfaces and method of using such a fabric is disclosed. The paving fabric includes thermoplastic materials and is combined with asphalt cement to provide a flexible, stress relieving, waterproofing layer for roadways. Because of the thickness and asphalt cement absorption of the fabric, the system provides a stress absorbing interlayer to resist fatigue and reflective cracking in pavements. The system also acts as an effective moisture barrier due to the enhanced capability to retain sufficient asphalt cement when paved onto a roadway. Such a system has the required strength and elongation to be installed on smooth or milled surfaces yet is easily milled and recycled owing to the uniquely engineered tensile and tear strengths of the fabric.