CATEGORY 500 PAVING SECTION 524 — DOWEL BAR RETROFIT
524.01 Description
Place load transfer devices or dowel bars between two slabs in an existing Portland Cement Concrete (PCC) Pavement. Place dowel bars into slots cut across cracks or joints and backfilling with grout.
524.02 Materials
524.02.01 Plain Reinforcement. Dowel bars used as ties in PCC pavement expansion and contraction joints shall be plain round steel bars conforming to A615, Grade 60 or A36 unless otherwise specified. Bars shall be epoxy coated using epoxy powder conforming to 917.02. Each dowel bar shall be coated with a water insoluble lubricant as approved.
524.02.02 Expansion Caps. Use tight-fitting, commercial quality end caps made of a non-
metallic, non-organic material that allows for 1/4 in. of movement at each end of the dowel bar. 524.02.03 Dowel Bar Support Chairs. Chairs for supporting the dowel bars shall be either completely epoxy-coated steel conforming to A 884 or fabricated of commercial quality nonmetallic, non-organic material. The dowel bar chairs shall firmly hold the dowels centered in the slots during the fast setting grout backfill operations. Dowel chairs shall be designed to hold the bar a minimum of 1/2 in. above the bottom of the slot while the fast setting grout backfill is placed and consolidated.
524.02.04 Foam Core Insert . Use 3/8 in. thick foam core inserts to re-establish the joint or crack
and allow each side of the slot to expand and contract. The inserts shall consist of rigid Styrofoam material or closed cell foam, faced with poster board or plastic material. The width of the foam board in its final position shall be 1/16 in. wider than the slot to minimize movement of the foam board and prevent incompressible material from entering the contraction joint during concrete placement. The width of the foam core board may need to be increased for pavements with skewed cracks or joints.
524.02.05 Grout Material. Refer to 902.14. Use Class II or Class III Rapid Hardening
Cementitious Material to backfill the dowel bars. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
524.03 Construction
524.03.01 Equipment.
a.Saw. Create the slots using a power-driven gang type assembly saw equipped with diamond saw blades. The saw shall be capable of sawing to the dimensions described without damage to the surrounding pavement.
b.Jack Hammers . Use a 30 lb jack hammer. Use a 15 lb hammer if the pavement is damaged by the 30 lb hammer.
524.03.02 Cleaning. Clear the area of all cuttings and other material after the saw cutting and jack
hammering are complete. Clean the slot of all foreign material and remove from the job site. Sand blasting equipment may be used to remove all foreign material from the exposed surfaces. Provide a cleaned concrete surface free of spalls, latence, and all contaminants detrimental to achieving an adequate bond.
524.03.03 Dowel Bar Installation. Install the dowel bars in the existing PCC pavement as
specified in the Contract Documents and as follows:
a.Place the dowel bar slots according to Standard No. MD 580.01. Place all dowels parallel to the surface, to each other, and to the edge of the lane along the joint or crack. Multiple saw cuts parallel to the centerline may be required to properly remove the material from the slot.
b.Saw the pavement to a depth to place the dowel bar at mid-depth in the pavement section. The saw cuts for the slots at each transverse crack or transverse joint shall be made such that the dowel bars are placed within the tolerances as specified in 524.03.01(a).
c.Remove the concrete from the slot without damaging the surrounding pavement.
d.Sand blast and clean all exposed surfaces and cracks in the slot prior to bar installation.
e.Use bar chairs to provide a 1/2 in. clearance between the bottom of the dowel bar and the bottom of the slot and chair such that the dowel bar is secured in place during placement of the grout. Place the dowel bars at the depth shown on the details, parallel to centerline and the top of the roadway surface, and at the middle of the slot, all within the specified tolerances.
1.Dowel bar placement for skewed cracks shall be within 2 in. of the required transverse spacing requirements.
2.Dowel bar placement for perpendicular cracks or joints shall be within 1 in. of the required transverse spacing requirements. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
f.Place the foam core inserts at the middle of each dowel bar to maintain the transverse contraction joint so that the foam core board fits tightly around the dowel bar and to the bottom and edges of the slot. Minimize movement of the foam board and prevent incompressible material from entering the contraction joint during concrete placement. Ensure that the insert extends up to the bottom of the existing joint sealant reservoir. If no sealant reservoir exists, the top of the foam core board shall be flush with the top surface of the concrete pavement.
g.Thoroughly moisten all surfaces on the sawed slot prior to filling with patching compound. Remove excess water with compressed air.
h.Fill the slot with the installed dowel bar, chairs, and foam core board in place with grout material. Vibrate the grout material with a small hand-held vibrator capable of thoroughly consolidating the patching compound into the slot and around the dowel bar. Trowel finish and cure the top surface of the filled slot. Curing compound shall meet 902.07.03.
i.Saw and seal the transverse cracks and transverse contraction joints as shown according to Standard No. MD 580.01.
524.04 Measurement and Payment
Dowel Bar Retrofit will be measured and paid for at the Contract unit price per each dowel bar placed and accepted. The payment shall be full compensation for saw cutting, jack hammering, dowel bars, form core, chairs, grout, expansion caps, clearing and hauling waste material, and for all equipment, material, labor, and all incidentals necessary to complete the work. Repair or replace dowel bar retrofits that are non-functioning or damaged at no additional cost to the Administration. 525 — PORTLAND CEMENT CONCRETE SPALL REPAIR CATEGORY 500 PAVING SECTION 525 — PORTLAND CEMENT CONCRETE SPALL REPAIR
525.01 Description
Repair spalled areas at various locations as specified in the Contract Documents or as directed. Spalling consists of small areas of cracking, breaking, chipping, or fraying of Portland Cement Concrete (PCC) slabs that typically occur within 2 ft of the edge of joints. Some spalling may occur in the middle of the slab away from the joints.
525.02 Materials
Rapid Hardening Cementitious Materials for Concrete Pavement Repair Portland Cement Concrete Mix #9 using No 7 aggregate Epoxy Adhesive 902.14 902.10 921.04
525.03 Construction
Repair spalled areas according to the following.
525.03.01 Repair Guidelines.
a.Rapid Hardening Cementitious material or Portland Cement Concrete Mix #9 using No. 7 aggregate may be used in spalled areas that are less than 4 ft2 and less than 3 in. deep.
b.Use Portland Cement Concrete Mix #9 using No. 7 aggregate only in spalled areas are 4 ft2 or greater or when the known depth is 3 in. deep or more. Rapid-hardening cementitious materials with extender aggregate may be used instead of Mix #9.
c.The maximum repair width shall not be greater than one-third of the travel lane. (d) Repair areas greater in width than one-third of the travel lane, deeper than one-third of the slab thickness, or where reinforcing steel is exposed as a Type I or Type II full- depth patch as specified in Section 522. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
Source: Maryland Standard Specifications for Construction and Materials, 2025 Edition. Pages 709–711 of 1,113.