Rev. 9-1-95

CONCRETE FOR PATCHING BRIDGE STRUCTURES

729-B-009

The Standard Specifications are revised as follows:

SECTION 729, BEGIN LINE 1, INSERT AS FOLLOWS:

SECTION 729 -- CONCRETE FOR PATCHING

BRIDGE STRUCTURES

729.01 Description. This work shall consist of the removal of existing concrete from outside the deck area of a bridge structure and replacing such concrete with new mortar or concrete in accordance with 105.03.

729.02 Materials. The cement shall be portland cement type I, or portland cement type I with the addition of an air entraining admixture to the concrete. Cement content shall be 335 kg/m3 (564 lb/cu yd). The net water added shall produce a slump of not more than 100 mm (4 in.). Air entrainment in the concrete mix shall be from 5 to 8 percent by volume.

Mortar shall consist of one part portland cement to two parts No. 23 sand. Concrete shall be in accordance with 722.04 for bridge deck patching concrete.

729.03 Construction Requirements. Removal of unsound concrete and protection of reinforcing steel shall be in accordance with 722.05(a)2. The slope of the cavity may be such that a thin layer of unsound concrete exists along the periphery of the hole before placement of the mortar or concrete. This condition shall be corrected by making a vertical cut of a minimum depth of 25 mm (1 in.) or to the top of reinforcing steel, whichever is less, at least 25 mm (1 in.) outside the originally spalled area, before the mortar or concrete is placed.

Power-driven hand tools for removal by handchipping, as set out above, will be permitted in accordance with 722.05(a)2.

Cleaning of the existing concrete surface shall be in accordance with 722.05(b).

Cavities of 13 mm (1/2 in.) in depth or greater shall be filled with concrete. Cavities less than 13 mm (1/2 in.) in depth, shall be filled with mortar.

729.04 Method of Measurement. This work will be measured by the square meter (square foot). Individual patches of 0.5 to 1.0 m2 will be measured as 1 m2. Individual patches of less than 0.5 m2 (1 sq ft) will not be measured for payment. All faces of a multi-faced patch will be measured accordingly for payment.

729.05 Basis of Payment. This work will be paid for at the contract unit price per square meter (square foot) for concrete, A, patching.

Payment will be made under:

Pay Item - -----------------Metric Pay Unit Symbol (English Pay Unit Symbol)

Concrete, A, Patching. . . . . . . . . . . . . . . . . . . . .m2 (SFT)

The areas where the patching exceeds an average of 100 mm (4 in.) in depth will be paid for at a price to be determined by multiplying the contract unit price for concrete, A, patching by the following factors:

(a) For portions thereof whose average depth is greater than 100 mm (4 in.) but not more than 150 mm (6 in.) 1.25

(b) For portions thereof whose average depth is greater than 150 mm (6 in.) but not more than 200 mm (8 in.) 1.50

(c) For portions thereof whose average depth is greater than 200 mm (8 in.) but not more than 250 mm (10 in.) 1.75

(d) For portions thereof whose average depth is greater than 250 mm (10 in.) but not more than 300 mm (12 in.) 2.00

(e) For all portions thereof whose average depth is greater than 300 mm (12 in.), the work shall be done as extra work. Payment will be made in accordance with 104.03.

The costs of removing the existing concrete; furnishing, hauling, and placing all materials; preparing the surface; individual patches of less than 0.5 m2 (1 sq ft); and all necessary incidentals shall be included in the cost of this work.