Elastic Sub-Base Structure for Fatigue-Resistant Pavement
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Solution Overview
Problem
Existing pavement systems face challenges in effectively utilizing recycled tire waste and improving fatigue life due to issues such as air void restrictions and rubber swelling, leading to costly repairs and reduced durability.
Innovation Solution
Incorporating recycled tire rubber as an elastic aggregate in the sub-base layer using a dry process, which enhances the elasticity and distributes traffic loads, thereby improving fatigue resistance by at least 25% compared to non-elastic sub-base layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dry process is used to incorporate recycled tire rubber in surface layer, then rubber recycling quantity increases by 700%, but air void control becomes technically difficult due to rubber swelling
Solution Approach 1:
The invention changes the physical state and distribution parameters of rubber by using it as aggregate in the sub-base layer rather than as surface modification. This allows the rubber to function structurally without causing air void issues in the surface layer, resolving the contradiction between recycling quantity and air void control precision
Solution Approach 2:
The invention moves the rubber application from the traditional horizontal dimension (surface layer) to a vertical dimension (sub-base layer), allowing rubber recycling without interfering with surface layer air void requirements. This dimensional shift enables both high rubber recycling and proper air void control in surface layers
2Strength
If conventional rigid base layer is used, then structural support is provided, but fatigue life is reduced due to stress concentration
Solution Approach 1:
The invention changes the mechanical parameter of the base layer from rigid to elastic by incorporating recycled tire rubber. This elastic property allows the base layer to absorb and dissipate traffic loads through deformation, reducing stress concentration and extending fatigue life while maintaining structural support capability
Solution Approach 2:
The invention creates a composite elastic base layer by combining recycled tire rubber with base layer materials. This composite structure provides both structural support and elastic deformation capability, resolving the contradiction between strength and fatigue life
3Reliability
If recycled tire rubber is used in surface layer, then skid resistance and durability improve, but environmental problems persist from tire waste piles
Solution Approach 1:
The invention recovers recycled tire rubber from waste piles and reuses it as functional aggregate in the sub-base layer. This transforms the harmful waste material into a valuable resource, eliminating environmental problems while improving pavement durability through elastic load distribution
Solution Approach 2:
The invention converts the harmful rigid rubber material from tire waste into a beneficial elastic aggregate that improves pavement performance. By changing the application context from surface modification to sub-base aggregate, the rubber's durability becomes an asset rather than a liability
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 use of recycled tire rubber in the sub-base layer significantly enhances pavement durability and fatigue life, ensuring structural stability and reducing the need for expensive repairs.
Implementation Method 1
the elastic property of rubber, the pavement durability is enhanced since the stress is dissipated rather than concentrated at certain points in a rigid system
Data Source
AI summary
A fatigue-resistant flexible road structure that includes one or more sub-base structural support layers positioned over a compacted earth foundation. At least one of the sub-base structural support layers is an elastic sub-base layer for more completely distributing surface loads. The elastic sub-base layer includes aggregate, filler, binder, and recycled tire rubber. The recycled tire rubber is included in an amount of 3% to 5% by weight of the sum of aggregate, filler, and rubber. The elastic sub-base layer has a fatigue life at least 25 percent greater than a non-elastic sub-base layer without recycled rubber. Further, the elastic sub-base layer has a modulus of elasticity at least 25 percent lower than a non-elastic sub-base layer without recycled rubber.