Short answer

Designers and engineers can confidently specify concrete mixes incorporating recycled aggregate and fly ash, provided appropriate fiber reinforcement and admixtures are used, to achieve sustainable and durable pavement solutions.

Field
Sustainability
Source
Construction Materials (2026)
Method
Experimental research and life-cycle assessment.
Sample
18 concrete mixtures (15 modified, 3 control)
Evidence
Strong effect

Incorporating recycled concrete aggregate and fly ash, along with polypropylene fibers and superplasticizers, can create high-performance concrete for road applications that meets stringent strength and durability requirements while significantly reducing environmental impact. This sustainability research insight is drawn from a 2026 study published in Construction Materials. Using Experimental research and life-cycle assessment. with 18 concrete mixtures (15 modified, 3 control), researchers explored how this design variable affects real-world outcomes. The key design takeaway: Designers and engineers can confidently specify concrete mixes incorporating recycled aggregate and fly ash, provided appropriate fiber reinforcement and admixtures are used, to achieve sustainable and durable pavement solutions.

Study
SustainabilityNew This WeekStrong effect

Recycled Concrete Aggregate and Fly Ash Enhance Road Pavement Durability and Sustainability

Incorporating recycled concrete aggregate and fly ash, along with polypropylene fibers and superplasticizers, can create high-performance concrete for road applications that meets stringent strength and durability requirements while significantly reducing environmental impact.

Construction Materials · 2026

01

Key Findings

  • 01Modified concrete mixtures with 10-12% fly ash replacement and at least 2 kg/m³ of polypropylene fiber achieved compressive strengths of at least 50 MPa and flexural strengths of no less than 5 MPa.
  • 02Abrasion resistance was significantly enhanced, ranging from 0.48–0.50 g/cm².
  • 03The environmental impact assessment showed reduced Global Warming Potential, Non-renewable Primary Energy Demand, and Abiotic Depletion Potential compared to conventional concrete.
  • 04The modified compositions meet required performance criteria for rigid pavement applications.
02

Application

Design takeaway

Designers and engineers can confidently specify concrete mixes incorporating recycled aggregate and fly ash, provided appropriate fiber reinforcement and admixtures are used, to achieve sustainable and durable pavement solutions.

How to apply

When designing concrete mixes for infrastructure projects, explore the inclusion of recycled concrete aggregate and fly ash, carefully optimizing fiber content and admixtures to meet performance specifications and sustainability goals.

Project actions

  • 01When researching materials, consider the environmental impact and potential for using recycled or waste components.
  • 02Document the performance trade-offs when substituting materials and how additives can mitigate these.
03

Method & Evidence

AimTo investigate the feasibility of using recycled concrete aggregate (RCA) and fly ash (FA) in fiber-reinforced concrete for road and airfield applications, and to determine optimal mix designs that achieve comparable performance to conventional concrete while offering environmental benefits.
MethodExperimental research and life-cycle assessment.
ProcedureResearchers developed and tested 15 modified concrete mixtures using RCA as a full gravel replacement and FA as a partial cement substitute, incorporating polypropylene fibers and superplasticizers. Three control mixtures with natural aggregate were also tested. Workability was standardized, and key performance indicators such as compressive strength, flexural strength, and abrasion resistance were evaluated. A cradle-to-gate life-cycle assessment was conducted for the constituent materials.
Sample18 concrete mixtures (15 modified, 3 control)
ContextCivil engineering, construction materials, sustainable infrastructure.

Variables

IV["Percentage of recycled aggregate used","Percentage of fly ash used as cement substitute","Content of polypropylene fiber","Content of superplasticizer"]
DV["Compressive strength","Flexural strength","Abrasion resistance","Brittleness index","Workability (slump)"]
CV["Slump class (S1)","Aggregate type (full gravel replacement)","Fiber length (36 mm)","Design age for strength testing"]
04

Strengths & Limitations

Strengths

  • +Comprehensive experimental testing of multiple mix designs.
  • +Inclusion of a life-cycle assessment to quantify environmental benefits.
  • +Focus on practical applications in road construction.

Limitations

The availability and consistency of recycled aggregate and fly ash can vary, potentially affecting mix design and performance.

Reliability & validity

The study's validity is supported by rigorous experimental testing and a life-cycle assessment. Reliability could be further enhanced by repeating tests on multiple samples for each mix design and potentially exploring a wider range of material sources.

Think critically

How might the variability in the properties of recycled aggregate and fly ash impact the consistency and reliability of the final concrete product in large-scale construction projects?

05

Design Principles

"Maximize resource circularity by integrating waste materials into high-performance applications without compromising structural integrity or durability."

This research demonstrates a practical pathway to achieving a circular economy in construction by repurposing waste materials into durable, high-performance road infrastructure. It offers designers and engineers a viable method to balance performance demands with environmental responsibility, reducing reliance on virgin resources.

06

What This Means for Your Design

You can build strong roads using old concrete and industrial byproducts like fly ash, making them last longer and be better for the environment.

How to use in your project

  • 1.Use this study to justify the selection of sustainable materials in your design project, referencing its findings on performance and environmental benefits.
07

Add to My Project

08

Quick Cite

Paragraph starter

This research by Kryzhanovskyi et al. (2026) demonstrates that incorporating recycled concrete aggregate and fly ash into fiber-reinforced concrete can yield materials with performance characteristics comparable to conventional concrete for road applications, while simultaneously advancing sustainability goals through waste material utilization and reduced environmental impact.

09

Source

Construction Materials

Design of Recycled Aggregate Fiber-Reinforced Concrete for Road and Airfield Applications Using Polypropylene Fibers and Fly Ash

journal · 2026

View source

Questions About This Research

What does the research say about recycled concrete aggregate and fly ash enhance road pavement durability and sustainability?
Designers and engineers can confidently specify concrete mixes incorporating recycled aggregate and fly ash, provided appropriate fiber reinforcement and admixtures are used, to achieve sustainable and durable pavement solutions. Evidence: Construction Materials (2026).
Why does "Recycled Concrete Aggregate and Fly Ash Enhance Road Pavement Durability and Sustainability" matter for design?
This research demonstrates a practical pathway to achieving a circular economy in construction by repurposing waste materials into durable, high-performance road infrastructure. It offers designers and engineers a viable method to balance performance demands with environmental responsibility, reducing reliance on virgin resources.
How can designers apply this research?
Designers and engineers can confidently specify concrete mixes incorporating recycled aggregate and fly ash, provided appropriate fiber reinforcement and admixtures are used, to achieve sustainable and durable pavement solutions.
What were the main findings?
Modified concrete mixtures with 10-12% fly ash replacement and at least 2 kg/m³ of polypropylene fiber achieved compressive strengths of at least 50 MPa and flexural strengths of no less than 5 MPa.. Abrasion resistance was significantly enhanced, ranging from 0.48–0.50 g/cm².. The environmental impact assessment showed reduced Global Warming Potential, Non-renewable Primary Energy Demand, and Abiotic Depletion Potential compared to conventional concrete.. The modified compositions meet required performance criteria for rigid pavement applications.
What research method was used?
Experimental research and life-cycle assessment. with 18 concrete mixtures (15 modified, 3 control).
How strong is the evidence?
Evidence strength is rated Strong effect, based on a 2026 journal from Construction Materials.
What should I do differently in my next project?
When designing concrete mixes for infrastructure projects, explore the inclusion of recycled concrete aggregate and fly ash, carefully optimizing fiber content and admixtures to meet performance specifications and sustainability goals.
What are the limitations?
The study focused on a specific range of RCA and FA percentages, polypropylene fiber content, and superplasticizer dosage. Long-term performance under varied environmental conditions and traffic loads was not assessed.