9.10 Equipment

9.10 EQUIPMENT

9.11 TEMPLATE FOR CHECKING GRADES ON DRIVES ON URBAN PAVING PROJECTS

Appendix 9-2

If field conditions necessitate a change in driveway grades, vehicle clearances should be checked using typical automobile template dimensions. This can be accomplished by using a scale model template to check plotted grades for new driveways. Keep in mind that there are exceptions to all rules and there may be cases when more clearance may be required than indicated by the template. In critical locations it may be necessary to contact the Office of Design for help in determining a revised driveway design.

9.12 ~~USE AND CARE OF WHEELED SURFACE CHECKER~~ RESERVED FOR FUTURE USE

Paving surface checkers must be used on all paving jobs to check areas of pavement that do not require a contractor furnished profilograph. The project engineer should obtain a surface checker from the Office of Materials.

To adjust surface checker, place it on steel master straightedge (wheels down) and adjust set screws and lock nuts until they are all equal distance from the face of the straightedge. This adjustment should be made at least once each day. Check daily with a 3 mm (1/8 inch) strap iron gauge. A string drawn across the tread of the wheels is not recommended.

To use a surface checker, place it longitudinally with one pair of wheels two feet from outer edge of pavement and push or pull it in a direction parallel to centerline. On the return trip, straddle centerline. On the last trip over slab, position is the same as for the first pass except on the opposite side of centerline. The wide spacing should always be used to check pavement smoothness.

~~Care of surface checker:~~

~~Keep shipping crate~~
~~At night, leave surface checker where it will not get run over or walked on. Be sure to avoid leaving it in a position that may cause warping.~~
~~Clean and oil wheels and bearings frequently using a light oil such as “fine oil” or “sewing machine oil”~~
~~When job is completed, crate surface checker in the same manner as it was crated when received by project engineer and return as directed to Office of Materials.~~

9.13 ACCUMULATION OF MATERIALS IN TRANSPORTING VEHICLES

Specification 2301.13D requires periodic cleaning and flushing of any transporting equipment, such as transit mixers, agitators, and wet batch trucks, to prevent accumulation of hardened concrete in the compartment. This specification also includes central plant mixing equipment. The

receiving hopper

for the elevating belt conveyor on auto-graders (Iowa Specials) and belts on placer/spreader machines should be checked for hardened concrete. Frequent inspection of transporting vehicles and hoppers should help assure prevention of accumulation and build-up of hardened concrete.

9.14 PCC FINISHING MACHINES

Specification 2301.07.A.6.b

Equipment normally associated and approved for hand methods shall not be substituted for a finishing machine on mainline paving. Bridge deck finishing machines are not approved for placement of slipform paving when a finishing machine is required, due to their lack of adequate consolidation equipment.

Repeated breakdown of a piece of paving equipment is sufficient reason to suspend paving operations until the machine is repaired and brought in proper operating condition or replaced.

9.15 OPERATING FINISHING EQUIPMENT ON PREVIOUSLY PLACED CONCRETE IN MULTIPLE-LANE CONSTRUCTION WORK

Concrete paving train equipment may be permitted to travel on an adjacent lane when concrete has attained the age of three days and beam breaks show a modulus of rupture of 3.45 MPa (500 psi) or more when the maturity method is not used. When the maturity method is used, the required strength must be obtained. This allowance is not intended to allow concrete batch trucks to haul on the newly placed concrete pavement. Concrete batch truck traffic will need to use other means to reach the paving operation until the pavement has reached the strength and age requirements of Specification 2301.31 or the Maturity Method per Materials I.M. 383.

Protection of Pavement
Wheels of finishing equipment operating on previously placed pavement shall be rubber faced. Track propelled equipment shall be equipped with rubber protective pads on crawler tracks or tracks shall travel on cushions of wood or belting. The near edge of wheels or tracks shall not be closer than 75 mm (3 inches) from edge of pavement. Provisions must also be made to prevent the screed from damaging ~~edge of~~ the existing pavement surface.

Surface Cleaning
When placing a lane adjacent to completed pavement, any spillage or flow of concrete slurry on the surface of existing pavement must be ~~broomed~~ cleaned off prior to hardening. This helps prevent the ~~transverse~~ tined grooves from being filled with concrete which would reduce the effectiveness of the textured surface.

Other Equipment
All other traffic and equipment, except as provided in Construction Manual 9.16, must be kept off pavement until age requirements specified in Specification 2301.31 are met.

9.16 EQUIPMENT WEIGHT LIMITATIONS ON NEW PAVEMENTS & PCC OVERLAYS

Specification 2301.31

Joint Cleaning & Sealing Equipment Used on New Pavement & Unbonded PCC Overlays
A minimum pavement age of 24 hours and strength of 1 MPa (150 psi) is required prior to allowing cleaning and sealing equipment on the new pavement slab. Both the tow vehicles and trailers must meet the axle weight restrictions in Appendix 9-4. Equipment used in the initial joint cleaning only may be operated on the new pavement slab after a minimum pavement age of 18 hours, as long as axle loadings do not exceed 75% of the axle weight restrictions ( Appendix 9-4). All vehicle tires must be pneumatic. The vehicles used must have a minimum axle spacing of 1.5 m (5 feet). A maximum of 3 axles may be used on any trailer. These restrictions do not apply when concrete strength is measured by the maturity method and the opening strength is reached prior to the time restrictions.

Sawing Equipment Used on Bonded PCC Overlays
Sawing equipment, including span saws, can be operated on bonded PCC overlays as soon as the new pavement will support the equipment without damage to pavement surface or joint edges.

Joint Cleaning and Sealing Equipment Used on Bonded PCC Overlays
Only equipment for initial joint cleaning may be operated on new pavement, following joint sawing, provided pavement surface and joint edges are not damaged. Axle weights are restricted to 75% of values specified in Appendix 9-4.

Weight limitations and conditions listed above for new pavements apply for all other equipment used after initial joint cleaning, until opening strength (and age without maturity) is reached.