96E03/29/06

S640-96E.doc

  -----------------------------------------------------------------------
  When hydrodemolition is used in the contract, include the following:

  -----------------------------------------------------------------------

**Section 640. - REMOVAL OF CONCRETE BY HYDRODEMOLITION**

**Description**

**640.01** This work consists of removing concrete with high pressure
water jets.

**Material**

**640.02** Conform to the following subsection:

> Water 725.01(c)

**Construction Requirements**

**640.03 General.** Submit a proposed sequence and schedule to the CO
for acceptance. Include the proposed removal method, list of removal
equipment, and operator certifications.

Submit the proposed method for filtering wastewater. Use methods such as
filters and sediment traps to ensure that wastewater released into the
environment is free of concrete particles and sediment. Dispose of all
debris off the project according to Subsection 203.05.

Construct structurally adequate debris shields to prevent debris and
wastewater from entering waterways, travel lanes open to public traffic,
or areas designated not to be disturbed.

Furnish all water required to operate the hydrodemolition equipment.

**640.04 Equipment.** Furnish a self-propelled and completely
programmable hydrodemolition system designed for concrete removal to
precise depths. Provide qualified equipment operators certified by the
equipment manufacturer.

Demonstrate and calibrate the hydrodemolition equipment in a 5 square
yard test area identified by the CO. Establish the operating parameters
to be used for production work to the CO for approval.

**640.05 Concrete Removal.** In the presence of the CO, use a hammer,
chain or other acceptable means to test the concrete surface and
determine the soundness of the concrete. Identify and mark all concrete
to be removed at least one day in advance of the hydrodemolition
operation.

Using hydrodemolition equipment, remove the designated concrete to a
minimum depth of 1 inch below the bottom of the top mat of reinforcing
steel. If needed, recalibrate the equipment during production to obtain
satisfactory concrete removal. Also remove all loose and unsound
concrete below the minimum depth.

In areas inaccessible to the hydrodemolition equipment, use acceptable
hand-held water blasting equipment or power-driven hand tools such as
jackhammers, mechanical chipping tools, or chipping hammers to remove
the designated concrete.

Do not damage remaining sound concrete or reinforcing steel. When the
bond between existing concrete and reinforcing steel is destroyed,
remove the concrete adjacent to the reinforcing steel to a depth that
permits new concrete to bond to the entire periphery of the reinforcing
steel.

If necessary, use hand tools such as hammers and chisels to remove the
final particles of concrete to achieve the required depth. Leave a rough
surface after the concrete is removed. Remove debris immediately after
the demolition operation to prevent it from rebonding to the surface or
reinforcing steel.

**640.06 Reinforcing Steel.** Do not cut or damage reinforcing steel
designated to remain. Use methods acceptable to the CO to repair or
replace all reinforcing steel damaged by the concrete removal operation.

**640.07 Surface Preparation.** Before placing new concrete, clean the
concrete surface and all exposed reinforcing steel of all rust, loose
and rebonded material, and other contaminants that may inhibit a bond
with new concrete. If compressed air is used, provide a filter in the
airline to ensure that the air delivered is oil-free. Protect the steel
and surface from contamination until the new concrete is placed.

**640.08 Acceptance.** Removal of concrete by hydrodemolition will be
evaluated under Subsection 106.02.

**Measurement**

**640.09** Measure removal of concrete by hydrodemolition by the square
yard of surface area removed.

**Payment**

**640.10** The accepted quantity, measured as provided above, will be
paid at the contract price per unit of measurement for the pay item
listed below that is shown in the bid schedule. Payment will be full
compensation for the work prescribed in this section. See Subsection
109.05.

Payment will be made under:

**Pay Item Pay Unit**

64001 Removal of concrete (hydrodemolition) Square yard