Recycled Concrete Pavement and Other Recycled Materials in Concrete Pavements

Recycled Concrete Pavement and Other Recycled Materials in Concrete Pavements Infrastructure Applications Utilizing Recycled Materials in South Carolina

What/Who is NRMCA? National Ready-Mixed Concrete Association Funded by Member Companies Mission - Serve Industry and Partners Through: Education Certifications Operations Research & Engineering Codes & Standards Advocacy Promotion Sustainability

Recycling Potential Recycled Content Typical Potential 0-25% 0% 15-70% 10-100% 0% 10-50%

NRMCA Sustainability Initiatives Outlines goals for reducing environmental footprint Provides strategies for achieving goals solar reflectivity, thermal mass, CO 2 absorption, pervious concrete, durability 4

NRMCA Sustainability Initiatives Embodied energy - Reduce 20% by 2020 30% by 2030 Carbon footprint - Reduce 20% by 2020 30% by 2030 Potable water - Reduce 10% by 2020 20% by 2030 Waste - Reduce 30% by 2020 50% by 2030 Recycled content - Increase 200% by 2020 400% by 2030 5

Concrete Structures in Transportation

Concrete Structures in Transportation

Supplementary Cementitious Materials Fly Ash Slag Cement Silica Fume

Fly Ash Use in Ready Mixed Concrete ACAA 2008 Survey 72 M Tons Produced 16 M Tons in Cement and Concrete 41 M Tons Landfilled (58%) 2000 PCA Survey >50% of all Ready Mixed Concrete had Fly Ash 15 to 40% Fly Ash is Typical High Volume Fly Ash Mixtures >40% What happens to concrete performance with increased fly ash?

Supplementary Cementitious Materials Properties of Fresh Concrete Type F Fly Ash Type C Slag Cement Silica Fume Water Demand Lower Lower Lower Increase Workability Increase Increase Increase Lower Bleeding and Segregation Lower Lower Inc./Lower Lower Setting Time Increase Inc./Lower Increase No Impact Air Content Lower Lower No Impact Lower Heat of Hydration Lower Inc./Lower Lower No Impact

Supplementary Cementitious Materials Properties of Hardened Concrete Type F Fly Ash Type C Slag Cement Silica Fume Early Age Strength Gain Lower No Impact Inc./Lower Increase Long Term Strength Gain Increase Increase Increase Increase Permeability/Absorption Lower Lower Lower Lower Alkali Silica Reactivity Lower Lower Lower Lower Sulfate Resistance Increase No Impact Increase Increase Freezing and Thawing No Impact No Impact No Impact No Impact

High Volume Fly Ash: Bleeding and Finishing Low w/cm High Volume Fly Ash (HVFA) Concrete: May Have Low Bleeding Possibly Slow Bleed Rate Higher Chance of Plastic Shrinkage Cracking

To Prevent Plastic Shrinkage Cracking Good Fogging Bad

Cementitious Admixture Interactions Sometimes Very Delayed Setting (> 3 days), Poor Strength Development Possible Mostly in Hot Weather Aluminate-Sulfate Interactions Class C Fly Ash Contributes Aluminates

Options for Water Use in Concrete Potable Non Potable or Recycled Wash Water

Recycled Water in Concrete Mixtures Clarified Wash Water (or Clearwater) Concrete Wash Water (or Greywater)

Standards for Mixing Water ASTM C 1602 Standard Specification for Mixing Water Used in the Production of Hydraulic Cement Concrete ASTM C 1603 Standard Test Method for Measurement of Solids in Water

C 1602 Sources of Water Potable Use Without Testing Qualify for No Harm Before Use: Non-Potable Water from Concrete Production Operations Combined Water Blends of One or More Sources

Water and Solids Management Varies From Simple to Complex: 1) Dump Concrete, Wash Into Pit or Pond 2) Dump Concrete, Wash Into Lined Sedimentation Pit w/recycled Water 3) Basic Reclaimers 4) 100% Recycling Reclaimers ( Zero-Discharge ) 5) 100% Recycling System w/hsas* (*Hydration Stabilizing Admixtures)

Options for Wash Water Use Clarified Water Can be Used at 100% Need to Handle Solids Gray Water: Test Density Daily Mix Gray and Fresh Water to Target Density Combined Water: Test per Table 1 Hydration Stabilizing Admixtures Can Help When Using Water With High Solids

Use of Wash Water In Concrete Control Solids Content Blending to Constant Density Accommodate Effects of Hydrated Cement Utilize Hydration Stabilization Admixtures (HSAs)

C 1602 Qualification of Water TABLE 1 Concrete Performance Requirements for Mixing Water (Mandatory) Compressive strength, min % control at 7 days A Limits Test Methods 90 C 31/C 31M, C 39/C 39M Time of set, deviation from control, h: min A From 1:00 early to 1:30 later C 403/C 403M A Comparisons shall be based on fixed proportions for a concrete mix design representative of questionable water supply and a control mix using 100 % potable water or distilled water. (See Annex A1).

C 1602 Qualification of Water TABLE 2 Optional Chemical Limits for Combined Mixing Water (Optional) Max conc. in combined water Limits, ppm Test Methods Chloride as Cl - prestressed other reinforced concrete 500 1000 C 114 Sulfate as SO 4 3000 C 114 Alkalies as (Na 2 O + 0.658 K 2 O) 600 C 114 Total solids by mass 50,000 C 1603

Total Solids, (x 1000) ppm C 1602 Limit for Solids 50,000 ppm = Water Density of 1.03 About 15 lb. solids per cubic yard 150 100 ASTM Limit 50 0 1 1.03 1.06 1.09 Water Density, g/ml

Grey Water Reuse - Considerations Water Generated = Water Used Plant Volume / Job Schedule Return Volume Sources of Recycled Water Recycled Water Storage Capacity Recycled Water Characteristics Criteria for Mixing Mater Specification Limitations Quality Requirements

Zero Discharge Reclaimed Aggregates Recycler Plant Clear Water Slurry Pit Clear Water Slurry Water Courtesy: Szecsy

Recycled Concrete As Aggregate

Recycled Concrete as Aggregates Concrete Structures Concrete Pavements Returned Concrete

Recycled Asphalt Pavement as Aggregate Recycled Asphalt Pavements

Recycled Fine Aggregates Foundry Sands and Slags Crushed Concrete

Ready Mixed Returned Concrete 2007 US RMC production - 415 million yd 3 Returned Concrete - 20 million yd 3 (2-10%)

Motivation for Using CCA Sustainability Reduce diversion to landfills - 5 million yd 3 Conserve virgin aggregate Economic Save $75 to $300 Million/yr

RCA for Pavements (ACPA 2009) http://www.acpa.org/

Characteristics of RCA Ref: ACPA, Snyder

Effects on Fresh Properties

Effects on Hardened Properties

Effect on Durability

Research funded by RMC - REF Technical data on concrete containing CCA and evaluate its use in concrete Properties of CCA Concrete performance Guidance on use http://www.nrmca.org/research/eng_articles.asp

Thank You! Brian Killingsworth, P.E. Senior Director, Pavement Structures National Ready-Mixed Concrete Association Phone: (830) 438-2690 Mobile: (210) 508-4923 bkillingsworth@nrmca.org http://www.nrmca.org/about/staff-bio-bkillingsworth.asp