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Cavalline presentation 4 13-10

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Cavalline presentation

Cavalline presentation

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  • 1. 2010 Concrete Sustainability Conference 1 © National Ready Mixed Concrete Association Building Materials Reclamation Program Construction and Demolition Waste Used as Recycled Aggregates in Concrete: Solutions for Increasing the Marketability of Recycled Aggregate Concrete B tt T t T C lli of Recycled Aggregate Concrete Brett Tempest, Tara Cavalline, Janos Gergely, and David Weggel UNC Charlotte
  • 2. 2010 Concrete Sustainability Conference 2 © National Ready Mixed Concrete Association Building Materials Reclamation Program UNC Charlotte Building Materials Reclamation • Grant from the US Department of Energy P UNC Charlotte Building Materials Reclamation Program Overview • Purpose: – Develop innovative and cost-effective ways of diverting construction and demolition (C&D) waste from landfills h h li dthrough recycling and reuse – Possibly develop strategies that create small business opportunities • Ongoing research as part of this grant: – Reclamation and reuse of structural steel members – Use of gypsum wallboard as a soil amendmentUse of gypsum wallboard as a soil amendment – Use of concrete and masonry rubble as recycled aggregate in concrete materials
  • 3. 2010 Concrete Sustainability Conference 3 © National Ready Mixed Concrete Association Building Materials Reclamation Program UNC Charlotte Building Materials ReclamationUNC Charlotte Building Materials Reclamation Program Overview
  • 4. 2010 Concrete Sustainability Conference 4 © National Ready Mixed Concrete Association Building Materials Reclamation Program Introduction • Most RA used in ready-mixed concrete applications consists of crushed returned concrete. Introduction • Some components of C&D waste, particularly concrete slabs, beams, columns, and masonry walls can be crushed and graded into RA material.g • Use of C&D waste as RA in concrete has been successfully demonstrated • Acceptance and use have not become widespread, particularly in Charlotte and Mecklenburg County, North Carolina
  • 5. 2010 Concrete Sustainability Conference 5 © National Ready Mixed Concrete Association Building Materials Reclamation Program Goal of this Study: From a local/regional perspective, show that use of RA, produced from C&D waste, in concrete is Goal of this Study: – Technically feasible – Economically viable • Investigate the feasibility of developing a substantial supply of concrete-grade RA from C&D waste • Identify a range of potential concrete products that could t ti ll i t th RA f C&D tpotentially incorporate the RA from C&D waste • Synthesize feedback from those involved in the industry regarding i di t t id d f RA f C&D t– impediments to more widespread use of RA from C&D waste in concrete applications – incentives that could promote acceptance and use
  • 6. 2010 Concrete Sustainability Conference 6 © National Ready Mixed Concrete Association Building Materials Reclamation Program Current endpoint for RA comprised of C&D waste • Worldwide: – Europe has excelled at reusing high proportions of C&D Current endpoint for RA comprised of C&D waste Waste in new construction – RILEM and BRE have made strides towards a standard for recycled aggregate use in Portland Cement Concrete • In Mecklenburg County, North Carolina: – Low-grade usesLow grade uses • Fill material • Surfacing material for temporary roads • Some roadbed materialSome roadbed material – Temporary roads at the Landfill
  • 7. 2010 Concrete Sustainability Conference 7 © National Ready Mixed Concrete Association Building Materials Reclamation Program NCDOT R l d Agg g t U g • Allowed – Base course for roadway • Not Allowed – Hot mix asphalt NCDOT Recycled Aggregate Usage construction – Projects with special permission to include – Portland cement concrete – Miscellaneous recycled material NCDOT Specifications (2006 Edition) Division 1 – General Requirements Section 104-13 Recycled Products or Solid Waste Materials “It is the policy of the Department of Transportation to aid in reduction of materials that have become a part of our solid waste stream. To that extent the Department encourages contractors to initiate develop, and tili d t d/ t ti th d th t i t th futilize products and/or construction methods that incorporate the use of recycled or solid waste products…”
  • 8. 2010 Concrete Sustainability Conference 8 © National Ready Mixed Concrete Association Building Materials Reclamation Program NCDOT Recycled Aggregate Usage NCDOT Specifications Section 104-13 Subsequently outlines: NCDOT Recycled Aggregate Usage • Procedure for submitting a Recycled Products or Solid Waste Materials Proposal for approval. • Price adjustment provisions• Price adjustment provisions – Net savings can be shared with contractor under similar provisions to other Value Engineering P lProposals – In the case of a new, innovative use not utilized by NCDOT, will award a bonus payment ($500 to $$2,500) to the Contractor even if there is no net cost savings on the particular project.
  • 9. 2010 Concrete Sustainability Conference 9 © National Ready Mixed Concrete Association Building Materials Reclamation Program RA in Mecklenburg County North Carolina • 2005 statistics: – Concrete and other hardscape rubble comprised 8% of RA in Mecklenburg County, North Carolina the C&D waste produced – Approximately 28,000 tonnes R t i d t h lt d i• Recent economic downturn has resulted in a reduced intake of rubble materials (and overall C&D waste volume) • Currently, the C&D landfill has more internal demand for RA produced from C&D waste (for haul roads) than that which is being provided
  • 10. 2010 Concrete Sustainability Conference 10 © National Ready Mixed Concrete Association Building Materials Reclamation Program Case Study Idlewild Elementary School • Demolished portion of school was built in 1953. – Concrete slab-on-grade Case Study – Idlewild Elementary School – Reinforced and unreinforced masonry walls – Steel framed roof, some prestressed concrete double- tees
  • 11. 2010 Concrete Sustainability Conference 11 © National Ready Mixed Concrete Association Building Materials Reclamation Program C St d Idl ild El t S h lCase Study – Idlewild Elementary School
  • 12. 2010 Concrete Sustainability Conference 12 © National Ready Mixed Concrete Association Building Materials Reclamation Program On Site Testing Prior to Demolition • Concrete slab-on-grade – Documented location of portion of On-Site Testing Prior to Demolition Documented location of portion of slab to be crushed, graded, and returned to laboratory – Cores removed– Cores removed – Rebound hammer testing • Masonry walls – Documented location of walls to be crushed, graded, and returned to laboratory – Whole brick and whole clay tile samples removed
  • 13. 2010 Concrete Sustainability Conference 13 © National Ready Mixed Concrete Association Building Materials Reclamation Program Top Down Demolition Strategy • From demolition contractor’s standpoint, Top-Down Demolition Strategy advantageous for several reasons: – Concrete slab-on-gradeg remains in place until remainder of building is cleared from site • Ensures that equipment has a sound surface to traverse – Concrete slab is used as a sorting pad for othera sorting pad for other materials
  • 14. 2010 Concrete Sustainability Conference 14 © National Ready Mixed Concrete Association Building Materials Reclamation Program Top Down Demolition Sequence 1. Removal of hazardous materials such as asbestos 2. Removal of valuable metals (copper, non-critical steel Top-Down Demolition Sequence structures) 3. Demolition of non-masonry partition walls, drop ceilings, and fenestrationceilings, and fenestration 4. Collection and disposal of materials listed in #3 5. Demolition and removal of roof framing, decking and icovering 6. Demolition and removal of masonry partition and exterior walls 7. Demolition and removal of concrete slab
  • 15. 2010 Concrete Sustainability Conference 15 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 16. 2010 Concrete Sustainability Conference 16 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 17. 2010 Concrete Sustainability Conference 17 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 18. 2010 Concrete Sustainability Conference 18 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 19. 2010 Concrete Sustainability Conference 19 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 20. 2010 Concrete Sustainability Conference 20 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 21. 2010 Concrete Sustainability Conference 21 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 22. 2010 Concrete Sustainability Conference 22 © National Ready Mixed Concrete Association Building Materials Reclamation Program Crushing Operations • Portions of concrete slab and masonry walls were transported (separately) to demolition contractor’s crushing operations. Crushing Operations • Crushed and graded – Minimal additional work was required to ensure that the material stayed “clean.” – No additional equipment was added and no operational changes made prior to crushing and grading of the material.
  • 23. 2010 Concrete Sustainability Conference 23 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 24. 2010 Concrete Sustainability Conference 24 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 25. 2010 Concrete Sustainability Conference 25 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 26. 2010 Concrete Sustainability Conference 26 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 27. 2010 Concrete Sustainability Conference 27 © National Ready Mixed Concrete Association Building Materials Reclamation Program
  • 28. 2010 Concrete Sustainability Conference 28 © National Ready Mixed Concrete Association Building Materials Reclamation Program Characteristics of RACharacteristics of RA Gradation of RA and Recycled Brick Masonry Aggregates Produced from Idlewild Elementary School Demolition Rubble % Finer Sieve Opening [mm] Recycled Concrete Aggregate Recycled Brick Masonry Aggregate 19 100 10019 100 100 13 100 99.8 9.5 85.0 85.1 4.75 14.0 19.5 2.36 3.0 0.8 Pan 0.0 0.0
  • 29. 2010 Concrete Sustainability Conference 29 © National Ready Mixed Concrete Association Building Materials Reclamation Program Characteristics of RACharacteristics of RA Characteristics of RA and Recycled Brick Masonry Aggregates Produced from Idl ild El t S h l D liti R bblIdlewild Elementary School Demolition Rubble Characteristic Recycled Concrete Aggregate Recycled Brick Masonry Aggregate B lk D it 1 281 975 5 (ASTM C29Bulk Density (kg/m3 ) 1,281 975.5 (ASTM C29 shoveling procedure) Absorption (%) 7.6 12.2 Abrasion Resistance (% lost) TBD 43.1 (% lost)
  • 30. 2010 Concrete Sustainability Conference 30 © National Ready Mixed Concrete Association Building Materials Reclamation Program Characteristics of RBMACharacteristics of RBMA Composition of Recycled Brick Masonry Aggregate Material % by weight % by volumey g y Clay brick 64.5 63.9 Clay tile 2.1 1.9 Mortar 30.1 31.6 Other (rock porcelain 3 3 2 6Other (rock, porcelain, lightweight debris) 3.3 2.6
  • 31. 2010 Concrete Sustainability Conference 31 © National Ready Mixed Concrete Association Building Materials Reclamation Program Development of Concrete Applications • Ongoing research • Portland Cement Concrete Development of Concrete Applications – Recycled concrete aggregate (slab-on-grade) – Recycled brick masonry aggregate (brick masonry walls) • Development of concrete mixture designs mechanical• Development of concrete mixture designs, mechanical properties • Geopolymer Concrete R l d ( l b d )– Recycled concrete aggregate (slab-on-grade)
  • 32. 2010 Concrete Sustainability Conference 32 © National Ready Mixed Concrete Association Building Materials Reclamation Program Geopolymer Concrete BeamsGeopolymer Concrete Beams with Recycled Aggregates
  • 33. 2010 Concrete Sustainability Conference 33 © National Ready Mixed Concrete Association Building Materials Reclamation Program Geopolymer Concrete BeamsGeopolymer Concrete Beams with Recycled Aggregates
  • 34. 2010 Concrete Sustainability Conference 34 © National Ready Mixed Concrete Association Building Materials Reclamation Program Development of Concrete Applications • Overall: – Careful source separation of reasonable quality C&D Development of Concrete Applications p q y waste materials has resulted in production of a relatively consistent RA. – Concrete incorporating RA (up to 100% replacement) produced from C&D waste obtained at the case study site has exhibited acceptable fresh properties andsite has exhibited acceptable fresh properties and mechanical properties. • Findings to be presented in subsequent publications• Findings to be presented in subsequent publications
  • 35. 2010 Concrete Sustainability Conference 35 © National Ready Mixed Concrete Association Building Materials Reclamation Program Local and Regional Market for RA • Demolition Contractors Local and Regional Market for RA – Input from Those Involved in the Industry Demolition Contractors • Aggregate Producers • Concrete Producers • Impediments preventing widespread acceptance d f RA i tand use of RA in concrete • Possible incentives that could be used to promote use of RA in concretep – Particularly RA from C&D waste
  • 36. 2010 Concrete Sustainability Conference 36 © National Ready Mixed Concrete Association Building Materials Reclamation Program Impediments to Use of RA in Concrete – • Existence of on site and low grade uses for RA Impediments to Use of RA in Concrete Perspective of Aggregate Producers • Existence of on-site and low-grade uses for RA • Potential for unsteady supply of source material • No examples of large scale use • Conflict with other cost centers within a company • Equipment costs Li it d f hi di l ti• Limited awareness of crushing as a disposal option • Availability of illicit dump sites • Quarries have a political advantage in large projectsQ p g g p j
  • 37. 2010 Concrete Sustainability Conference 37 © National Ready Mixed Concrete Association Building Materials Reclamation Program Impediments to Use of RA in Concrete – • Ready supply of virgin aggregates in the Mecklenburg Impediments to Use of RA in Concrete Perspective of Concrete Producers y pp y g gg g g County, NC area • Preference for returned material, if RA is used Known composition enhances comfort level– Known composition enhances comfort level • Storage space and handling requirements – Space at a premium at many facilities – Cost to up-fit existing facilities with storage and conveying systems can be significant • Lack of experience with recycled materials – Additional training and guidance, grounded in research and field study is needed
  • 38. 2010 Concrete Sustainability Conference 38 © National Ready Mixed Concrete Association Building Materials Reclamation Program Incentives and Tactics to Promote the Use of RA • Waive tipping fees for higher quality rubble at crushing Incentives and Tactics to Promote the Use of RA – Input from Aggregate Producers g g g operations – Offset cost of hauling • Provide income tax credits – Identified as perhaps the incentive of most interest • Create demand from project owners – Tax credits for use or other incentives to encourage selectiong over virgin aggregates • Create more stationary/permanent crushers – Capable of producing more consistently graded material
  • 39. 2010 Concrete Sustainability Conference 39 © National Ready Mixed Concrete Association Building Materials Reclamation Program Incentives and Tactics to Promote the Use of RA • Explore potential products and markets Incentives and Tactics to Promote the Use of RA – Input from Concrete Producers Explore potential products and markets – Lower-strength uses such as footings • Consolidate operations – If a single facility could receive and crush C&D wasteIf a single facility could receive and crush C&D waste, quarry virgin aggregates, and batch concrete, development of mixtures containing appropriate quantities of RA would be more feasible. • Engineers submit their own quality control plan – For use on niche projects (such as buildings seeking LEED certification), specifications from engineer regarding source material handling prequalification tests for mixtures andmaterial handling, prequalification tests for mixtures, and additional testing requirements.
  • 40. 2010 Concrete Sustainability Conference 40 © National Ready Mixed Concrete Association Building Materials Reclamation Program Conclusions • In Mecklenburg County, North Carolina, RA produced from the existing stream of C&D waste is currently Conclusions directed to non-concrete low-grade applications. • Shortage of field experience with RAC in North Carolina• Shortage of field experience with RAC in North Carolina has delayed interest in and acceptance of the material by engineers, contractors, and suppliers. M h h d id RAC h b t d– Much research and guidance on RAC has been centered on RA produced from returned concrete. – Additional research focusing on performance of RA from C&D d b f dC&D waste sources needs to be performed.
  • 41. 2010 Concrete Sustainability Conference 41 © National Ready Mixed Concrete Association Building Materials Reclamation Program Conclusions • Apprehension regarding use of C&D waste as RA based upon: Conclusions – Potential for contamination of source material with other debris – Inconsistent physical properties • “Top-down” demolition approach has been shown to address these concerns – Already routinely utilized by many demolition contractors – Has been shown to produce relatively clean and uniform sources of RA with satisfactory characteristics for PCC applications.
  • 42. 2010 Concrete Sustainability Conference 42 © National Ready Mixed Concrete Association Building Materials Reclamation Program Conclusions • Concrete incorporating up to 100% RA produced from the case study site has been shown to exhibit acceptable Conclusions performance. – Findings to be presented in subsequent publications C t d li t i ith RA• Concrete producers can realize cost savings with RA – If supply and consistency of C&D waste increases, improved market interest in RA should follow. – Remaining impediments include: • Equipment and operational cost barriers • Other economic issues such as tipping fees, hauling costs,pp g , g , and increased product development expenses
  • 43. 2010 Concrete Sustainability Conference 43 © National Ready Mixed Concrete Association Building Materials Reclamation Program Acknowledgements • United States Department of Energy Acknowledgements • DH Griffin Wrecking Company • DH Griffin Grading & Crushing • Concrete Supply Company• Concrete Supply Company • Vulcan Materials • Argos USAArgos USA • National Ready Mixed Concrete Association
  • 44. 2010 Concrete Sustainability Conference 44 © National Ready Mixed Concrete Association Building Materials Reclamation Program Thank you Questions?Thank you… Questions?