Published by department of transportation

50-1.02 MATERIALS

50-1.02A General

Organic zinc-rich primer must be on the Authorized Material List for organic zinc rich primer.

50-1.02B Prestressing Steel

Epoxy-coated strand must comply with ASTM A882/A882M, grit impregnated coating, including annex A1.

Bars must comply with ASTM A722/A722M, Type II, including all supplementary requirements, except the maximum weight requirements do not apply. The reduction of area of bars with deformations removed must be at least 20 percent.

If couplers are used to extend bars:

1. Assembled units must have a tensile strength of at least the manufacturer's minimum guaranteed ultimate tensile strength of the bars

2. Location of couplers in the member must be authorized

Package the prestressing steel in containers or shipping forms that protect the steel against physical damage and corrosion during shipping and storage. Except for epoxy-coated strand, a corrosion inhibitor that prevents rust or other results of corrosion must be (1) placed in the container or shipping form, (2) incorporated in a corrosion-inhibitor-carrier-type packaging material, or (3) applied directly to the steel if authorized.

Corrosion inhibitors must not have a deleterious effect on the steel, concrete, or bond strength of the steel to concrete.

Clearly mark each shipping container or form with:

1. Statement that the package contains prestressing steel

2. Type of corrosion inhibitor used

3. Date packaged
Immediately replace or restore any damaged container or shipping form to its original condition.

Do not store epoxy-coated strand within 1,000 feet of ocean or tidal water for more than 60 days.

Patching material for epoxy-coated strand must be:

1. Furnished by the manufacturer of the epoxy powder

2. Applied under the manufacturer's instructions

3. Compatible with the original epoxy powder material

4. Inert in concrete

50-1.02C Grout

Cement must comply with section 90-1.02B(2).

Water must comply with section 90-1.02D.

Admixtures must comply with section 90-1.02E except admixtures must not contain chloride ions in excess of 0.25 percent by weight.

The efflux time of grout immediately after mixing must be at least 11 seconds. Determine the efflux time under California Test 541.

Secondary grout must:

1. Comply with ASTM C1107

2. Not have a deleterious effect on the steel, concrete, or bond strength of the steel to the concrete

50-1.02D Ducts

Ducts for prestressing steel must:

1. Be galvanized rigid ferrous metal.

2. Be fabricated with either welded or interlocked seams except galvanizing of the welded seams is not required.

3. Be mortar tight.

4. Have sufficient strength to maintain their correct alignment during placing of concrete.

5. Have positive metallic connections at joints between sections that do not result in angle changes at the joints.

6. Have waterproof tape at the connections.

7. Have bends that are not crimped or flattened.

8. Have ferrous metal or polyolefin transition couplings connecting the ducts to anchorage system components. Ferrous metal transition couplings need not be galvanized.

9. Have an inside cross-sectional area of at least 2.5 times the net area of the prestressing steel for multistrand tendons.

10. Have an inside diameter of at least 1/2 inch larger than the diameter of the bar.

11. Have an outside diameter not exceeding 50 percent of the girder web width.

Furnish all ducts or anchorage assemblies with pipes or other suitable connections for the injection of grout after prestressing.

50-1.02E Vents

Vent all ducts having a vertical duct profile change of 6 inches or more. Vents must:

1. Be at least 1/2-inch-diameter standard pipe or suitable plastic pipe.

2. Be connected to ducts using metallic or plastic structural fasteners. Plastic components must not react with the concrete or enhance corrosion of the prestressing steel and be free from water soluble chlorides.

3. Be mortar tight and taped as necessary.

4. Provide a means for injection of grout through the vents and for sealing the vents.

50-1.02F Permanent Grout Caps

Permanent grout caps for anchorage systems of post-tensioned tendons must:

1. Be glass-fiber-reinforced plastic with antioxidant additives. The environmental stress-cracking failure time must be at least 192 hours under ASTM D1693, condition C.

2. Completely cover and seal the wedge plate or anchorage head and all exposed metal parts of the anchorage against the bearing plate using neoprene O-ring seals.

3. Have a grout vent at the top of the cap.

4. Be bolted to the anchorage with stainless steel fasteners complying with ASTM F593. All fastener components must be alloy 316.

5. Be pressure rated at or above 150 psi.

50-1.02G Debonding Sheathing

Sheathing for debonding prestressing strand must:

1. Be split or un-split flexible polymer plastic tubing

2. Have a minimum wall thickness of 0.025 inch

3. Have an inside diameter exceeding the maximum outside diameter of the strand by 0.025 to 0.14 inch

Split sheathing must overlap at least 3/8 inch.

Waterproofing tape used to seal the ends of the sheathing must be flexible adhesive tape.

The sheathing and waterproof tape must not react with the concrete, coating, or steel.

50-1.02H Anchorage System

The anchorage system for post-tensioning must:

1. Be capable of holding the prestressing steel at a force producing a stress of at least 95 percent of the specified ultimate tensile strength of the steel

2. Permanently secure the ends of the prestressing steel

3. Be equipped with permanent grout caps

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