Jerry L. Larson IRMCA Indiana LTAP Basics of a Good Road Concrete Pavement: Selection of Concrete Materials Jerry L. Larson IRMCA Indiana LTAP Basics of a Good Road INDIANA CHAPTER

Basic Components of a Concrete Pavement Surface smoothness or rideability Thickness Design Longitudinal joint Transverse joint Surface Texture Concrete materials Dowel bars Tiebars Subgrade Base

How Pavements Carry Loads 6600 LBS. 6600 LBS. Flexible Pavement pressure < 0.2 MPa pressure » 2.0 MPa Concrete’s rigid panels spread the load over a large area reducing pressure on the sub grade.

Conventional Concrete Pavement Types Full Depth New Construction Reconstruction Overlays Thin Overlays

Concrete Design “Optimize” Cost Performance

Subbase vs. NO Subbase Heavy Traffic?? > 120 Trucks/day = subbase Fine grain soils prone to erosion Presence of moisture/water Potential pumping Presence of all or most above conditions suggests need for subbase

Successful Concrete Pavement Design Requires Selecting Appropriate Features Subgrade modification Drainage system Subbase Joint Spacing 18 ft 15 ft Dowels Thickness 8 in 10 in 12 in Reinforcement Joint Sealant None Hot pour Silicone Preformed Surface Texture Transverse tine Burlap drag Shoulder Asphalt Concrete

Maximum top size coarse aggregate 0.75 - 1.0 in. Concrete Mix Design INDOT Class C Fast Track INDOT Class A Material (per cubic yard) Cement (Type I) 564 lbs. Cement (Type III) 708 lbs. (658 lbs.) Fly Ash (50 lbs.) Coarse Aggregate * 1750 lbs. 1425 lbs. Fine Aggregate 1250 lbs. 1350 lbs. Mix designs very greatly between various parts of the country. However the primary differences between a standard pavement design and a high early or fast track mix design is generally the amount of cement used and the admixture dosages and combinations. Often an accelerating admixture in added at the plant to increase the heat of hydration thereby increase the concrete set times and allow for quicker opening to traffic. If a type III cement is available they are used as well. Water:Cement Ratio 0.45 max. 0.42 Water Reducer yes yes Air Entrainer ** yes yes * Maximum top size coarse aggregate 0.75 - 1.0 in. ** Air content 6% + 1.5%

Durability = Performance Quality Materials Aggregate – AP Approved, uniform gradation Minimum Cement Content Approved Admixtures Proper Mix Design – Control to Design Moisture/Water Control Air Entrainment – 6% + 1.5% Proper Curing – Liquid membrane applied @ manufacturer’s suggested rate

Panel Design Plan 12 – 20 FT Profile or

Jointing Spacing based on thickness > 12” thick - saw 1/3 the depth 6” thick – 12’ joint spacing > 12” thick – 18’ joint spacing > 12” thick - saw 1/3 the depth If not specifying dowels – can skew joints 1’ in 12’ across pavement High volume traffic – seal joints with silicone or neoprene Low volume traffic – seal joints with hot pour rubberized asphalt

Dowels or NO Dowels The slabs ability to share its load with its neighboring slab Dowels High Traffic Volumes (Pavements > 8 in.) Aggregate Interlock Low Traffic Volumes (Pavements < 7 in.) L = x U = 0 Poor Load Transfer Good Load Transfer L = x U

Surface Texture Tineing

Surface Texture Light Broom

Surface Texture Drag Finish

Construction - Reconstruction

Construction - Reconstruction

Overlays Expected Performance Condition of existing sub-grade/pavement UTW (2” – 4”) – 15 to 20 years Thicker overlays (4” – 6”) 20 to 25 years Condition of existing sub-grade/pavement Clearance issues – if none, can build on top of old PCCP or HMA pavement

Concrete Resurfacing Applications Concrete overlays for concrete pavements: Bonded Concrete Overlays Unbonded Concrete Overlays Concrete overlays for asphalt pavements: Conventional Whitetopping Ultra-Thin Whitetopping

Unbonded Overlay Consists of thick concrete layer (4” or greater) on top of existing concrete pavement. Uses a “separation interlayer” to separate new overlay and existing concrete. . . . . . .. . . .. .

Unbonded Overlays Separation Interlayer: “Key” Overlay Old Pavement Smooth Slip Plane Interlayer (1 in)

I-69 UNBONDED PCC OVERLAY PCCP over old Concrete Pavement

Conventional Whitetopping Consists of thick concrete layer (4 in or greater) on top of an existing asphalt pavement. Behaves as a new pavement on a strong base.

Typical Whitetopping Thickness Depends on expected traffic load. City streets, county roads, and small airports 4 to 7 in. Primary roads and interstate highways 7 to 11 in. Large airports 8 to 18 in.

Harding Street - Indianapolis Built in 1985 6” Overlay on old HMA pavement 8” thick on stone where widened Skewed Joints

PCCP over old Chip & seal road 121st St., Fishers

PCCP over 2 lane HMA street Allisonville Road PCCP over 2 lane HMA street

Allisonville Road Cross Section

UTW Schematic Thin Slabs (2 to 4 inches) Short Square Slabs Existing HMA Pavement Short Square Slabs (2 to 6 ft.) Milled Surface As we saw in the introductory session, this is a schematic of the UTW application. The existing HMA pavement is milled to enhance bond.

Market & Columbia Streets - Warsaw 3.5” PCCP over HMA, Gravel, & Brick

Demonstration in 2002 Typical mill and fill job in older cities…you never know just what you're going to find under the surface.

Photo by Indiana Public Works.com Magazine

Joints were established at 5’ intervals based on slab thickness

Warsaw Whitetop July 2005 October 2002

Concrete Roads and Streets

Concrete Intersections & Roundabouts US 31 & SR 32 US 6 & US 421 Gray Rd. & 96th St. Pontiac Ave. & Wayne Trace, Ft. Wayne 96th St. approaching Keystone Ave.

Pervious Concrete

Summary KNOW YOUR OPTIONS

Indiana Ready Mixed Concrete Association Questions? Contact: Jerry L. Larson (317) 634-8989 jlarson@irmca.com Indiana Ready Mixed Concrete Association (317) 872-6302 www.irmca.com INDIANA CHAPTER