Improving the Strength of Concrete using Demolition Waste

Improving the Strength of Concrete using Demolition Waste

Ummam Shitab, Anupam Kumar Gautam

Environmental engineering Maharishi University of Information technology

Abstract:

Thisresearchexploresthepotentialof usingdemolition waste as an alternative material for strengtheningconcrete. Concrete is one of the most widely used construction materials, but the environmental impact associated with its production and disposal is substantial. Demolition waste, which includes materials like crushed bricks, concrete, and tiles, can be repurposed to reduce the need for virgin aggregates and lower the carbon footprint of concrete production. The study evaluates various mixes, testing methods, and performance characteristics, ultimately aiming to develop an improved concrete formula with sustainable practices. The research concludes that using demolition waste in concrete mixes can enhance certain properties like compressivestrengthwhilepromoting environmentalbenefits.

1. INTRODUCTION:
   1. Background: Concrete is one of the most essential materials in the construction industry. It accounts for a significant portion of the global construction market. However, its production requires large amounts of natural resources and results in significant CO emissions. The construction sector also generates a substantial amount of waste, particularly demolition waste. Globally, millions of tons of demolition waste are produced each year, yet much of it remains underutilised.
   2. Problem Statement: While concrete is widely used, its production and disposal have substantial environmental impacts. The use of demolition waste as an aggregate alternative in concrete production has emerged as a potentialsolution to reduceboththeenvironmentalimpact andtherelianceonvirginmaterials.
   3. Research Objective: The objective of this study is to investigate the use of demolition waste as a partial or complete substitute for natural aggregates in concrete production and assess its effects on the compressive strength anddurabilityoftheconcrete.
   4. Research Scope: Theresearch willfocuson:
      • Assessingthetypesof demolitionwastethatcan be used in concrete.
      • Conducting laboratory tests to compare the mechanical properties (compressive strength, tensile strength, etc.) ofconcretewith andwithout demolition waste.
      • Reviewingtheenvironmentalimplications ofusing demolition waste in concreteproduction.
2. LITER ATURE REVIEW:
   • 2.1 Concreteand Demolition Waste:
     1. • OverviewofConcreteComposition: Cement, aggregates(fineandcoarse),andwater.
        • Types of Demolition Waste: Concrete debris, bricks, tiles, asphalt, and wood, which are often disposed of in landfills.
        • Previous Studies on Recycling in Concrete: Research by authors such as Mardani-Aghabaglou et al. (2015) and Ramos et al. (2019) has shown positive results when using crushed concrete and other waste materials in concrete,oftenimproving sustainabilitywithoutcompromisingstrength.
   • 2.2 Advantagesand Challenges of Using Demolition Waste:
   1. • Advantages:
        • Reduceslandfillwaste.
        • Minimisestheextraction ofvirginaggregates, reducingtheecologicalimpact.
        • Canpotentiallyimprovecertainmechanical properties.
      • Challenges:

• Variability in the quality of demolition waste.

• Possiblecontaminationwithimpuritiesthat may affectconcreteperformance.
• Difficultyinstandardisingdemolitionwastefor widespread use.

• 2.3Strength andDurability ofConcretewith Demolition Waste:
  • Concrete properties, such as compressive strength, tensilestrength, and modulus of elasticity,arevital to structuralperformance.
  • Effect of Demolition Waste on Strength: While some studies report a decrease in compressive strength, others suggest that by optimising mix ratios, certain types of demolition waste can enhance strength or provide comparable resultsto natural aggregates.
  • 3. MATERIALSANDMETHODS:
• 3.1 Materials Used:
  • Cement: Ordinary PortlandCement(OPC).
  • Aggregates: Natural aggregates (sand and gravel) and demolition waste aggregates (crushed concrete, tiles, bricks).
  • Water:Potablewater.
    • 3.2Demolition WastePreparation:
    • Collection and Selection: Demolition waste is sourced from construction sites and processed (crushing, sieving, andwashing).
    • Characterisation: Analysis of the physical properties(sizedistribution,shape, moisture content)ofthe demolitionwaste.
      • 3.3 ConcreteMix Design:
    • Controlmixwithoutdemolitionwaste.
    • Experimental mixes with varying proportions of demolition waste as a replacement for natural aggregates (e.g., 10%, 20%, 30%).
    • Other additives or chemical admixtures may be consideredforbetterperformance.
      • 3.4 Testing Methods:
    • Compressive Strength Test: Using standard moulds, concretespecimens arecuredfor28 days and subjected to compression testing.
    • TensileStrengthandFlexuralStrength Tests: To evaluatetheoverallperformanceoftheconcrete.
    • Durability Tests: Freeze-thaw cycles, water absorption, and chemical resistance.
    • Microstructural Analysis: SEM(Scanning Electron Microscopy) may beused toinvestigate thebond between cement paste and aggregate.
    • 4. RESULTS AND DISCUSSION:4.1 Compressive Strength Results: Present the findings ofcompressive strengthfor eachmix, including controlandthosewith varyingdemolitionwaste proportions. Discuss trends such as:
      • Ifthereisan increaseordecreasein strength.
      • Theeffectofdifferenttypesofdemolitionwaste (bricks, concrete, tiles)on strength.
      • Comparewith relevantstudiesandbenchmarks.
      • 4.2 Durability and Other Properties: Discuss the resultsoftensilestrength, flexuralstrength, andany observed improvements orconcerns inthedurability of concrete with demolitionwaste.
      • 4.3 Microstructural Analysis: Discuss how the microstructure of concrete changes with the inclusion of demolition waste. Use SEMimagestoshowthebond between cement pasteand recycled aggregates.
      • 4.4 Environmental Impact: Calculate the carbon footprint of using demolition waste versus natural aggregates in concreteproduction. Highlightthe potential reduction in O emissions and the sustainable advantages.
      • 5. CONCLUSION:
        • 5.1Summary ofFindings:
          • Concludewhethertheuseofdemolitionwaste improves or reduces concrete strength.
          • Highlightanysignificantdifferences in properties likedurability, workability, andsustainability.
            • 5.2Recommendations forFutureResearch:
          • Investigatethepotentialuseofothertypesof demolition waste.
          • Furtherstudieson thelong-termdurabilityof concretewith recycledaggregates.
          • Examination of cost-effectiveness and scalability fortheconstructionindustry.
            • 5.3 ImplicationsfortheConstruction Industry:
          • Discusshowwidespread adoptionofthismethod could impact construction practices.
          • Explorepotentialpolicy changesfor encouraging theuse of demolition waste.REFERENCES:
            • Include studies and academic articles that have contributed to thedevelopmentof your research. For instance:
          • Mardani-Aghabaglouet al.(2015).”Utilisationof recycledaggregateinconcrete: Areview.”
          • Ramos et al. (2019).”Recyclingconstruction and demolition waste forsustainable concrete production.”
          • Other relevantstudies, standards, andbookson concrete technology and wastemanagement.

• Tables ofexperimental data.APPENDICES :
• Diagrams or charts comparingstrength and durability.
• Detailedmaterial specifications.

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