Emerging Concrete Pavement Solutions Concrete Overlays

Transcription

1 Emerging Concrete Pavement Solutions Concrete Overlays 19 th Annual Public Works Conference November 19th, 2015 Presenters: Victor Cervantes - Cemex Clay Slocum, P.E. - CNCA 1

2 Outline: History/Perspective Overlay overview Resources/Design Applications Environmental briefs Maintenance Cost Comparison Bellefontaine, Ohio 124 Year Old Concrete Pavement 2

3 California Concrete Pavements Have Performed Well Outperforming Their Design Lives ESAL (Million) California LTPP Test Sections & ESALs Carried (Million) Design ESALs Current ESALS or ESALs to 1st Rehab I-5, Siskiyou County I-15, San Diego County I-15, Riverside County Rte 2, Los Angeles County I-15, Riverside County I-8, San Diego County I-15, Riverside County I-5, Shasta County I-5, San Joaquin County I-5, San Joaquin County I-5, San Joaquin County Thickness Still Concrete Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Age at 1 st Rehab Current Age I-15, San Diego County * These concrete designs have carried 5 times more loads than for which they were designed LTPP (Long Term Pavement Performance) is 20 Year FHWA research project to monitor pavement performance Long Term Pavement Performance Database, California GPS 3, 4, and 5 Sections

4 California Was Once A Leader In Concrete Overlays A 1994 NCHRP study documented 31 different concrete overlay projects California Concrete Overlays Location Year Const Thickness (in) Highway 119, Taft to Bakersfield Los Angeles (87 street projects) California Highways (78 miles) Hamilton AFB Travis AFB to 13 Palmdale AFB to 14 Castle AFB Castle AFB and 18 Mather AFB Travis AFB I-5, Gorman US 99, Bakersfield US 99, Union Ave US 99 in Kern County US 99 in Madera County Los Angeles Airport and 15 US 99, Kern Co I-5, Los Angeles US 101, Los Angeles US 91, Orange Co I-5, Gorman (SBL) I-80, W. of Sacremento US 99, Bakersfield I-8, E of San Diego I-5, Project City I-8, San Diego Rt 163, San Diego and 8 US 99, Tulare Co I-5, Siskiyou

5 Where Is Caltrans Now?

6 Outline: History/Perspective Overlay overview Resources/Design Applications Environmental briefs Maintenance Bellefontaine, Ohio 124 Year Old Concrete Pavement 6

7 Concrete Overlays Fall Into Two Categories Concrete Overlays Bonded (Typical Thick = 2 to 6 in) Unbonded (Typical Thick = 5 to 11 in) Bonded Concrete Overlay of Concrete Pavements Bonded Concrete Overlay of Asphalt Pavements Bonded Concrete Overlay of Composite Pavements Unbonded Concrete Overlay of Concrete Pavements Unbonded Concrete Overlay of Asphalt Pavements Unbonded Concrete Overlay of Composite Pavements Bond is integral to design (Existing pavement is in relatively good shape) Old pavement is base (Existing pavement is in poor condition)

8 Structural/Functional Condition Where Do They Fit In The Pavement Rehab Curve Pavement Deterioration Curve Concrete Asphalt Excellent Good Bonded on Concrete Bonded on Asphalt Patching/DG & 2-4 AC Overlays Good Good Fair Poor Deteriorated Unbonded on Concrete Unbonded on Asphalt 3-8 AC Overlays 8 & Thicker AC Overlays Reconstruction (AC or PCC) Fair Fair Failed Age or Traffic Poor Poor Other Issues that dictate viability of an overlay Roadway type (Interstate vs Arterial vs Collectors) Site specific considerations shoulder, bridges, and other vertical clearance issues Traffic control options & Time to open Deteriorated Deteriorated

9 Outline: History/Perspective Overlay overview Resources/Design Applications Environmental briefs Maintenance Bellefontaine, Ohio 124 Year Old Concrete Pavement 9

10 Technical Guidance

11 Lots Of Other Guidance Is Also Available

12 Typical Design Thicknesses Typical Concrete Thickness for Urban Applications Typical Concrete Thickness for Rural Applications Interstate & Expressways Principal & Minor Arterials Collectors Interstate & Expressways Principal & Minor Arterials Collectors Bonded On Concrete Bonded On Asphalt Bonded On Composite Unbonded On Concrete Unbonded On Asphalt Unbonded On Composite Interstate & Expressways 4 lane or more divided highways with limited access Arterials - moderate or high-capacity roadways which typically carry vehicles for longer trips (many rural state highways are included in this category) Collectors collect & disperse traffic between arterials and local roads or from sections of neighborhoods (rural farm to market roads are included in this category)

13 Joints Tell The Concrete Where To Crack The concrete will crack after placement Drying shrinkage Changes in temperature and moisture Ambient (contraction) Gradient (curling) Subbase restraint (friction or bond) First applied loads Proper jointing provides a series of saw cuts (joints) spaced to control crack formation Joint Spacing depends on overlay type & thickness Bonded typically 12 to 18 times thickness (3 to 9 ft) Unbonded typically 18 to 24 times thickness (8 to 15 feet) Depth = 1/3 thickness Use small square shapes pay attention to inlets, manholes Best spacing is often controlled by street width Erratic crack patterns due to no joints

14 Short Joint Spacing Improves Performance Reduces environmental loading (curling & warping) and stresses in the slab Effect of Slab Length on Shrinkage Force Effect of Slab Length on Bending / Deflection Curling & warping is produced by the shrinkage force at the slab surface. Due to drying and thermal differential shrinkage on the surface of the concrete. The magnitude of this force is dependent on the length of the surface. Shorter slabs have less length, which means that shorter slabs have reduced curling All concrete slabs bend and deflect when loaded Reducing slab length reduces changes the primary response from bending to deflection Shorter jointing means slabs deflect more Longer (standard) jointing means slabs bend more, which increases tension on the bottom of the slab 15.0 ft 5.0 ft 5.0 ft 5.0 ft

15 Joint Layout Is Crucial To Performance BAD Jointing Practices Good Jointing Practices

16 Concrete Overlays of Existing Asphalt

17 Koke Mill Subdivision Springfield, Illinois 25 Years and Running

18 Outline: History/Perspective Overlay overview Resources/Design Applications Environmental briefs Maintenance Bellefontaine, Ohio 124 Year Old Concrete Pavement 18

19 Concrete Overlays On Main Roadways Durability & Costs Advantages Add strength and durability to an existing pavement Same longevity and cost benefits of traditional concrete Competitive on Initial & Life Cycle Cost A wide range of thicknesses can be used Can be designed to last from 10 to 40+ years before most major repairs are needed Coolidge Road, Michigan - 5 inch concrete overlay & widening - built September Picture circa 2001

20 Parking Lots - How The Construction Works Palm Springs City Hall - Before After Photo: Crystal Chatham/The Desert Sun Photo: Madrid Corporation Concrete Contractor -Productivity has significantly increased - up to 50,000 SF / day cutting labor costs and curing time -36 Contractors with this equipment in California - 10 are currently using the 3-D system which is best for overlays

21 Concrete Overlay - Intersections Benefits Non-deforming surface No softening from oil drippings Durable skid resistance Long service life Low-maintenance Concrete eliminates the significant rutting problems that sometimes occur with asphalt-surfaced roadways.

22 RCC IS PLACED WITH HIGH DENSITY ASPHALT PAVERS

23 Roller Compacted Concrete (RCC) As An Overlay RCC has long history of good performance on heavy duty pavements Roller Compacted Concrete Pavements No Slump Placed by asphalt pavers High production Compacted with vibratory rollers No forms, finishing, rebar, dowels Very affordable Historical RCC Uses 1970 s Logging industry sorting yard 1980 s Army Corp of Engineers dams, levees, linings 1990 s Ports 2000 s Streets and local roads Recently, city streets & highway shoulders have been successfully completed with RCC

24 % Total Weight RCC MIX DESIGN USES SAME MATERIALS AS CONVENTIONAL CONCRETE, HOWEVER IN DIFFERENT COMBINATIONS Achieves Similar or Better Engineering Properties Than Conventional Concrete Typical Mix Design Aggregate Gradation Conventional Concrete Roller Compacted Concrete Cement + FA Coarse Agg Fine Agg Water Properties Conventional RCC Compressive Str. (psi) 3,000-5,000 4,000-10,000 Flexural Str. (psi) ,000 Elastic Modulus million million Typical aggregate gradation of RCC (black on chart) is similar to aggregate gradation of intermediate HMA layer (blue on chart) Smaller top-sized aggregates = better looking surface Larger top-sized aggregates = higher strengths & higher load transfer

25 CEMEX Plant Access Road Victorville, CA 2015 Owner: CEMEX Use Type: Collector / Arterial Project Information Year Built: 2015 Quantity: 5,300 CY Thickness: 8 RCC / 3 AC / Stabilized Subgrade Natural Surface

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28 Outline: History/Perspective Overlay overview Resources/Design Applications Environmental briefs Maintenance Bellefontaine, Ohio 124 Year Old Concrete Pavement 28

29 U.S. Green Building Council - LEED CREDIT 7.1 Heat Island Effect: Non-Roof Requirements: Provide shade (within 5 years) Use light-colored/high-albedo materials (SRI 29) Use open grid pavement For at least 30% of the sites non-roof impervious surfaces OR Use an open-grid pavement system for a minimum of 50% of the parking lots area

30 Solar reflectance changes over time Image: US EPA

31 Enhance Safety Nighttime illumination differs, as illustrated by this overlay project Reflected illumination is roughly proportional to solar reflectance Source: Pomerantz, M., et al (2003)

32 Energy Savings Reduced energy for street lighting Enhanced illumination or fewer fixtures Remove 25% of the lights from your parking lots 39 light fixtures 27 light fixtures = Dark pavement Light pavement Source: Stark, R.A. (1986)

33 M.I.T. Research Stiffer Pavements Have Better Fuel Economy Asphalt deflects 2 to 5 times more than Concrete Concrete has 0.5-3% better fuel efficiency Based on a MIT Study for CALTRANS Pavements, 1% CA saving 9.1 million barrels of crude oil per year $520 million per year 2 million tons of CO2 per year Stiffer Structure means Concrete has lower Environmental Impact

34 Outline: History/Perspective Overlay overview Resources/Design Applications Environmental briefs Maintenance Bellefontaine, Ohio 124 Year Old Concrete Pavement 34

35 Diamond Grinding? Diamond Grinding Removal of thin surface layer of hardened PCC 1/10-1/4 inch deep Typically used to smooth old concrete pavements Uses closely spaced diamond saw blades High production Benefits Caltrans - time until additional rehab = 17 years Improves friction Reduces noise Rejuvenates surface aesthetics Typical cost $2 to $4 per square yard

36 Common Utility Cut Details * A full-depth cut should be made at any utility cut boundary that is not an existing joint for thicknesses of 7 in. (175 mm) and greater. ** For pavements thinner than 7 in. (175 mm), utility cut boundaries that are not at an existing joint should be cut to a depth of about one third of the slab thickness and the remainder of the depth removed with a jackhammer. *** Some agencies have had success with up to a 2 ft (0.6 m) layer of natural soil above the backfill but below the restored concrete pavement surface course.

37 Good and Poor Removal Practice

38 Excellent Practice

39 Lift-Out Method: No Single Method!

40 Maintenance of Thin Concrete Overlays Individual small panels can be quickly and easily replaced at a reasonable cost

41 Resources: Cemex California Nevada Cement Association National Concrete Pavement Technology Center Portland Cement Association American Concrete Pavement Association Lawrence Berkeley National Laboratories MIT Concrete Sustainability Hub Caltrans

42 Clay Slocum, P.E. (530) Victor Cervantes (310)