Crack-Resistant Cementitious Materials Using Recycled Aggregates
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Solution Overview
Problem
Current cementitious materials lack effective crack resistance and sustainability, particularly when using recycled aggregates and fibers, which are not adequately utilized in construction due to limitations in workability, strength, and environmental concerns.
Innovation Solution
Development of crack-resistant cementitious materials incorporating recycled steel fibers from scrap tires and reclaimed asphalt pavement as aggregate replacements, combined with optional recycled carbon fibers, to enhance ductility and cracking resistance without compromising compressive strength or impact toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fine reclaimed asphalt pavement is added to cementitious materials, then ductility and toughness are improved, but workability and compressive strength are reduced
Solution Approach 1:
The patent changes the physical and chemical parameters of the recycled asphalt pavement by subjecting it to hydraulic pressure washing and thermal treatment to remove contaminants and optimize surface properties. This allows the recycled asphalt to maintain better interfacial bonding with cement paste, improving workability while preserving the ductility and toughness benefits
Solution Approach 2:
The patent creates a composite material system combining recycled asphalt pavement particles with cementitious binder, optimizing the interface between the two materials through surface treatment. The composite structure allows the recycled asphalt to provide ductility enhancement while the treated surface maintains workability by improving compatibility with the cement matrix
2Reliability
If recycled steel fibers are used from scrap tires, then sustainability is improved, but manufacturing complexity increases due to fiber quality variation
Solution Approach 1:
The patent performs preliminary sorting and classification of recycled steel fibers before they are incorporated into the cementitious material. Fibers are pre-treated to remove rubber residues and categorized by length and diameter, which simplifies the manufacturing process by reducing variability and eliminating the need for complex quality control during production
Solution Approach 2:
The patent standardizes key parameters of the recycled steel fibers through controlled processing, including length, diameter, and surface cleanliness. By establishing consistent fiber specifications upfront, the manufacturing process becomes less complex as workers don't need to constantly adjust for fiber variability
3Object-generated harmful factors
If high replacement levels of recycled aggregate are used, then environmental impact is reduced, but compressive strength and fatigue resistance are compromised
Solution Approach 1:
The patent optimizes the gradation, size distribution, and surface characteristics of recycled asphalt pavement aggregate through controlled processing. By adjusting these parameters, the aggregate maintains better mechanical interlocking and interfacial bonding with the cement matrix, preserving compressive strength and fatigue resistance even at high replacement levels (up to 50% or more)
Solution Approach 2:
The patent creates an optimized composite system where recycled asphalt pavement aggregate is combined with cementitious binder and fiber reinforcement. The composite structure compensates for potential strength losses by distributing stresses more effectively, allowing high volumes of recycled aggregate to be used while maintaining mechanical performance
4Reliability
If crack resistance is improved through recycled materials, then material performance is enhanced, but the need for water reducers and additives increases
Solution Approach 1:
The patent enables the recycled asphalt pavement aggregate and recycled steel fibers to inherently provide crack resistance through their material properties and interfacial characteristics. The treated surface of recycled asphalt and the fiber reinforcement create a self-reinforcing system that reduces cracking without requiring additional chemical additives or water reducers
Data Source
AI summary
Provided herein are cementitious materials, for example, a crack-resistant cementitious mortar. The cementitious materials are a mixture of cement, at least one recycled fiber reinforcement material, a recycled aggregate material, and water. Also provided is a method for increasing the crack-resistance of a cementitious material by replacing the sand in a cement mortar with a recycled aggregate material and adding at least one recycled fiber reinforcement material and a volume of water.