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Section 30 – Concrete Structures

The location, manner, and duration of the application of the vibrators shall be such as to

secure maximum consolidation of the concrete without causing segregation of the mortar and

coarse aggregate. Vibrators shall not be attached to or held against the forms or the reinforcing

steel. The use of external form vibrators will only be permitted with written approval of the

Agency when the concrete is inaccessible for adequate internal consolidation, and the forms are

constructed sufficiently rigid to resist displacement or damage from external vibration.

Concrete in structures shall be tamped and consolidated by means of high frequency

internal vibrators of a size, type, and number as approved by the Agency. The number of

vibrators shall be sufficient to consolidate the incoming concrete within fifteen (15) minutes after

it is deposited in the forms. No less than two (2) serviceable vibrators shall be available at all

times. Surfaces shall be smooth and free from voids caused by rock pockets. Where

necessary, vibration shall be supplemented by hand spading to secure these results.

Non-epoxy bonding compounds shall be used for dry areas and epoxy resin bonding

compounds shall be used for areas exposed to moisture. Bonding compounds shall be applied

in accordance with the manufacturer's instructions.

Epoxy resins may be used for grouting dowels in concrete, crack injection, adhesive for

bonding fresh and hardened concrete, as a binder for epoxy mortar in making concrete repairs,

and under water. Some epoxies are not suitable for temperature extremes such as freeze-thaw

environments; placing shall be done within manufacturer’s allowable parameters. Epoxies may

be fast-setting when approved by the Agency. The epoxy binder and adhesive shall be two-

component mixture conforming to Section 95-2.01, "Binder (Adhesive), Epoxy Resin Base”, of

the State Specifications, and shall be mixed at the work site. Safety, proportioning, mixing, and

temperature are critical and shall be done according to manufacturer’s instructions. Aggregate

shall conform to Section 90-2.02, "Aggregates”, of the State Specifications. When using epoxy

as a binder to make mortar, the two components shall be thoroughly mixed to a uniform gray

color before the aggregate is added. Unless otherwise specified, the mix proportions shall be

one (1) part epoxy binder to four (4) parts aggregate by volume. When fine aggregate (sand) is

used, the mix shall be one (1) part epoxy binder to six (6) parts aggregate, by volume. The

aggregate shall have a moisture content of not more than one-half of one percent (0.50%) when

mixed with binder. The aggregate size and proportions shall be determined by the Contractor,

subject to the approval of the Agency.

Appropriate uses of epoxy resin shall conform to Section 95, “Epoxy”, of the State

30-9 CONCRETE PLACED UNDER WATER

Unless specifically shown or specified in the Contract, no concrete may be placed

underwater without written direction from the Agency.

When underwater placement of concrete is directed, the placement shall be by approved

tremie or bottom dump bucket. The consistency of the concrete shall be appropriate for

underwater placement and must be approved in writing by the Agency. Underwater placement

shall be continuous until completed. Placing concrete in running water will not be permitted.

30-10 EXPANSION JOINTS

When premolded joint filler is shown or specified in the Contract, the filler shall be anchored

in the correct position before concrete is placed. The edges of the concrete at the joint shall be

finished with a one-quarter inch (1/4”) radius edging tool. Unless otherwise specified in the